2A - Public Hearing and recommendation to City Council regarding the Historic Preservation/EnvironmeMEMORANDUM
TO: Environmental Advisory Board
Landmarks Preservation Advisory Board
FROM: Peter Pollock, Planning Director
Susan Richstone, Acting Long Range Planning Manager
James Hewat, Historic Preservation Planner
Chris Meschuk, Historic Preservation Planner
Matteo Moore, Historic Preservation Intern
Jim Gery, Residential Plans Examiner
Marie Zuzack, Project Manager
Sazah Van Pelt, Environmental Sustainability Coordinator
Elizabeth Vasatka, Environmental Coordinator
Carolyn Weinreich, Energy Sustainability Assistant
DATE: Apri121, 2006
SUBJECT: Historic Preservation/ Environmental Sustainability Integration Project
review, discussion and possible recommendation to City Council
Summary
• The key issue for this project is whether the city's policy on preservation
of historic windows should be modified to allow historic property owners
to replace them with new windows for energy efficiency reasons.
• The project also has explored potential conflicts between other historic
preservation policies/ guidelines and environmental sustainability policies/
guidelines, such as those relating to doors, solar collectors, skylights and
shutters.
• Based on reseazch and work with a panel of experts in energy, windows
and historic preservation, staff recommends basing the window
replacement policy on the historic significance of the elevation on which
the window occurs and the visibility of the window from the street.
• Staff also recommends modifying the Historic Preservation Guidelines
and Green Points Guidelines to clarify historic preservation values and
better integrate historic preservation and Green Points objectives.
• The Landmarks and Environmental boards are asked to discuss the ran~e
of policy options and the staff recommendation and to consider
formulating ajoint or separate policy recommendation to City Council.
Purpose
The purpose of this project is to identify common ground and resolve conflicts between
historic preservation and energy efficiency policies, programs, and guidelines, and to
propose changes where needed. The impetus for Ihe project was the well-publicized,
controversiai replacement of windows on a historic home in the Mapleton Hill Historic
District. Accordingly, the main focus of the project has been on windows: Whether the
improved energy efficiency of new windows warrants modifying the current historic
preservation guidelines that discourage replacement of historic windows, except in cases
of severe deterioration. Other environmental issues associated with window replacement,
such as waste reduction and resource conservation, also were explored. The project has
had to address the non-environmental reasons people cite for replacing old windows,
such as safety, comfort, maintenance, and operability. These aze strong motivating
factors that were continually raised throughout the project, even though they were outside
the original charge of the project.
In addition to the window issue, several other azeas of potential conflict or disconnect
between historic preservation and environmental sustainability guidelines were identified.
These include placement of solaz collectors, replacement of historic doors, roofing and
siding, and conservation of existing buildings.
Discussions among staff, [he Environmental and Landmazks boards, an ad hoc panel, key
stakeholders and the public revealed additional issues as well, including the perceived
lack of broad public awareness or understanding of historic preservation goals and
principles. One particular point of confusion has been about the importance of
maintaining historic materials, as artifacts from the past, versus maintaining historic
appearance. Some members of the public believe that the objective of the city's historic
preservation program is to maintain historic appearance, and don't realize that the
Historic Preservation Ordinance and Guidelines also call for the preservation of historic
materials. This objective has been adopted from the Secretazy of Interior's Standards for
Historic Building Rehabilitation, which stipulates that historic materials should be
preserved and only removed if they aze deteriorated beyond repair. Because of this
misunderstanding, some people believe that replacing historic windows with new
windows that look similar to [he originals is consistent with the city's current historic
preservation policies. Others understand but simply do not agree with the objective to
preserve historic materials.
Further confusing this issue is the historic preservation guideline that states that more
publicly visible historic materiais are more important to preserve than less visible ones.
This seems to contradict or discount the requirement to preserve historic materials, in
favor of simply maintaining a historic appearance visible to the public. Historic
preservation objectives regarding historic materials, historic appearance, and visibility to
the public need to be clarified through this project.
Embodied enerev issue
The issue of the "embodied energy" of an existing window was often brought up in
discussions of rehabilita[ing versus replacing windows for energy reasons. Some of the
public input and several articles by historic preservationists asserted that conserving
existing windows is "more environmental" than replacing them because of the embodied
energy in old windows. However, staff did not find, nor could the ad hoc panel
recommend, any scientific studies that prove this.
The staff team discussed this issue at length among itself and with the project ad hoc
panel. No one disputed that there is conservation of both energy and natural resources
when preserving historic windows, as well as savings in waste. However, there was no
agreement that these outweigh the long-term energy conservation and associated
greenhouse gas reduction that result from installing more energy-efficient new windows.
Advocates on the energy side pointed out that calculating a definitive answer to this
question would be very complex, and they tended to oppose making assumptions.
Attempting to settle this issue would be costly and time-consuming, so staff proposed that
this is beyond the scope of the project. The ad hoc panel supported this; they agreed that
staff and the panel did not have the resources to fully quantity the issue and should focus
instead on what they knew. Staff believes that a reasoned resolution to the project issues
is possible without a definitive answer to the embodied energy question.
Context
Approximately 1,200 buildings are protected under the Historic Preservation Ordinance.
Historic Preservation staff processes about 200 alteration certificate applications per year.
Staff estimates that the question of whether windows on a historic building can be
replaced comes up informally about once a month. Approximately six alteration
certificate applications are submitted per year requesting window (or pane) replacement.
These are approved or denied on a case-by-case basis, depending on the window type and
location.
A phone survey of several Colorado and peer cities revealed a mixture of approaches:
some cities allow replacement of historic windows, others strongly discourage it. See
Attachment A.
The city's current policies, regulations and guidelines regazding historic preservation and
environmental sustainability aze listed in Attachment B.
Information gathering
An ad hoc panel of five experts in energy efficiency, sustainable building, windows and
historic preservation was assembled to assist staff with technical analysis for the project.
At the first of two meetings, the panel reviewed and discussed the information available
on energy efficiency and historic windows. Staff assembled pertinent literature to create
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a set of baseline information (organized into a binder) and asked the ad hoc panel to
suggest additions or subtractions from the information set and also enquired whether
l~terature on solar collectors or other topics was needed. The panel members only
suggested a couple of additional studies on windows and endorsed the information set.
At their next meeting, the pane{ discussed key findings and facts from the baseline
information and their own experience.
For the public, highlights of each article/study were posted on the project Web page
(along with instructions on how to request a copy of any specific title) and made
available at a public forum, along with display copies of the entire binder.
Findings and facts
Staff and the ad hoc panel agreed on a set of findings and facts to present at the project
public forum on March 13. The Findings and Facts handout is shown in Attachment C.
This was not meant to be an exhaustive or exclusive list of all the facts associated with
historic windows and energy efficiency. Rather, it was provided as a selection of points
that were made by the panel and thought to be useful for informing discussions among
the public, boards and City Council.
The following were the key findings:
- Wea[herization: Repairing, sealing and weather-s[ripping can greatly improve the
energy efficiency of a leaky single-pane window.
- Sinele-~ane vs. double-pane: Double-pane windows lose less heat than single-pane
windows and can keep a house cooler in the summer. At today's energy prices, an
average house in Boulder with single-pane windows would pay approximately
$150-$300 more annually for heating and cooling than a house with double-pane
windows.
- Retrofitted sinele-pane vs. double-nane: Rehabilitating a single-pane window and
adding a storm window or a second pane can result in energy-efficiency close to
that of a new double-pane window.
- CosUPavback of new: Due to the relatively high cost of new windows, replacing single-
pane windows is rarely justified on the basis of energy cost savings alone.
Estimated payback period for new windows is usually several decades.
The greatest gain in energy efficiency comes from sealing and weather-stripping a leaky
single-pane window and adding a storm (or other second pane). Replacing that with a
low-e, gas-filled double pane window can further lower heat loss, but the incremental
energy saving is much smaller. Some of the baseline information showing this is
summarized in Attachment D.
During the presentation section of the public forum, the ad hoc panel members were each
asked to articulate what they believe are key information points about the energy
efficiency of rehabilitated historic windows versus new windows. Common themes in
their responses were the following:
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Rehabilitating a historic window can greatly improve its energy efficiency.
There are many ways to improve energy efficiency throughout a house besides
replacing windows.
The warranties that come with new windows are strong motivation for contractors
and homeowners to replace rather than restore historic windows.
The individual responses of the panel members can be found in Part 1 of Attachment E.
Options
Staff worked with the ad hoc panel to develop and evaluate a range of policy options for
consideration by the public, boazds and Council. The three options cover the spectrum
from allowing replacement of all historic windows (Option C) to prohibiting any
replacements (Option A).
The middle option on the spectrum, Option B, represents a compromise between historic
preservation and wholesale window replacemen[, based on the historic significance of the
elevation on which a window occurs and the window's visibility to the public. The
rationale is to offer homeowners flexibility where less historic significance is at stake,
while being more protective of elements that contribute the most to the city's historic
resources.
All three options would allow the addition of an insulating layer to a window if it dces
not remove underlying historic materials, for example, a storm window and a second
interior pane. In all options, non-historic windows, windows on non-contributing
buildings, and historic windows deteriorated beyond repair could be replaced. Any
replacement of a historic window would be required to replicate the material, design and
dimensions of the original as closely as possible. Similazly, storm windows should match
the material, proportions and profile of the underlying window as closely as possible.
Wood frame and steel frame windows would be treated the same under each option.
The policy for window replacement for each option would apply to historic doors as well.
Each option also addresses the placement of solar collectors, skylights and shutters.
Solar collectors come in a variety of forms: They can be panels that aze mounted on the
roof, an exterior wall, an awning, or the ground; or they can be roofing materials. They
can heat water or air directly, or they can generate electricity. Because of [heir various
and evolving forms, they would be treated as a single category, along with skylights, for
simplicity in implementation. Modern, automated shutters can save energy both by
insulating and by sealing air leaks, but they are not yet in widespread use. Web research
showed some models that may be compatible with the chazacter of local historic districts.
Photos of examples of shutters and solar collectors are in Attachment F.
Options Analysis
The two primary criteria for evalua[ing each option are the extent to which the option
would reduce energy consumption and preserve historic materials. Maintaining historic
appearance is secondary to maintaining historic materials. (Current policy and
regulations are shown in Attachment B.)
1) Option A: Most protective of historic materials
• Generally reflects cunent historic preservation guidelines
• Preserve, rehabilitate and weatherize all historic windows
• Shutters aze ailowed where historic precedent
• Solar collectors and skylights must be inconspicuous, not highly visible to public
• Replacement of deteriorated materials would require evaluation of window
condition (evaluation would entail form filled out by homeowner and submitted
with photos for review by staf~
• Esiimate one week for alteration certificate review/approval
Pros:
Consistent with Secretary of Interior Standards: Avoid removal of historic
materials; repair rather then replace
- Conservation of historic resources reduces waste and resource use.
- Repairing, sealing and weather-stripping historic windows and doors can
significantly reduce air leakage, improve operability, and cost less than
replacement.
- Addition of storm window or interior second pane can significantly reduce
air leakage and thermal loss, approaching energy performance of new
windows.
- Offers some predictability/ certainty/ consistency for homeowners/
applicants, except when determination must be made about deterioration.
Cons:
- Single-pane windows need to be retrofitted with a second interior pane or
an interior or exterior storm window to approach the energy efficiency of
new double-pane windows.
- Extensive restoration work may cost as much as installing a new window.
- May be inconsistent with locating solar collectors where sun exposure is
greatest.
2) Option B: Preservation based on elevation
Generally reflects current historic preservation practice
Replacement depends on historic significance of elevation the windows are on:
- Primary elevation ("fronY') - most historic significance; windows must be
preserved
- Secondary elevation ("side") - less significance; windows may be
replaced or must be preserved based on their visibility from public street
- Tertiary elevation ("rear") - least significance; windows may be replaced
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.
• Hierarchy and visibility of elevations determined by case-by-case building survey
(with specific criteria for determination)
• Replacement of deteriorated materiais would require evaluation of window
condition (evaluation would entail form filled out by homeowner and submitted
with photos for review by staffl
• Solar collectors and skylights allowed on roofs on secondary and tertiary
elevations
• Shutters are allowed on primary elevation if historic precedent, and on secondary
and tertiary elevations
• Estimate 1-2 weeks for alteration certificate review/approval
Pros:
Cons:
Generally consistent with Secretary of Interior Standards and with Historic
Preservation Guideline: Historic materials on elevations visible from
public street are more important.
Protects historic materials based primarily on historic value and
secondarily on visibility.
Window rehabilitation and replacement both reduce energy loss.
Compromise/ hybrid of Option A and Option C.
Offers least predictability/ certainty/ consistency for homeowners/
applicants. More complicated to understand and administer. May extend
review/approval timeline by a week.
May be inconsistent with locating solar collectors where sun exposure is
greatest, though more flexible than with Option A.
3) Option C: Most lenient, less preservation required
• Replacement of historic windows allowed on all elevations
• Replacements must replicate historic appearance as closely as possible.
• Solaz panels, skylights and shutters in any location
• Estimate one week for alteration certificate review/approval
Pros:
New double-pane windows, especially with low-e coating, are more
energy efficient than single-pane windows.
- New energy-efficient windows are available that closely replicate historic
windows.
- Offers most predictability/ certainty/ consistency for homeowners/
applicants.
- New double-pane windows do not have be seasonally installed/ removed
as some interior and exterior storm windows do, are less likely to
experience condensation, and may be easier to clean.
- New windows comply with and often exceed safety code requirements.
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- Solar collectors/panels may be piaced to maximize sun exposure.
Cons:
Inconsistent with Secretary of Interior Standards and city historic
preservation guidelines: Avoid removal of historic materials; replace only
when deteriorated beyond repair. This may jeopardize the city's Certified
Local Govemment status with the National Pazk Service. which could
make the city ineligible for federal Historic Preservation Fund grants.
- New windows are only somewhat more energy efficient than single-pane
windows with storm windows or retrofit[ed with interior second pane.
- Energy bill savings rarely justify cost of window replacement.
- There are many other, potentially more cost-effective ways to improve
energy efficiency of old buildings.
- Removal of historic materials is irreversible; once they're gone, they're
gone forever.
Evaluation of different energy-efficiency window treatments
Each of the three options allows a different range of window treatments for improving
energy efficiency. Each of these window treatments differs in how well it reduces energy
consumption and preserves historic materials. The matrix on Attachment G shows which
treatments would be allowed under each option and gives a relative indica[ion of how
weil each treatment meets those two primary criteria. The matrix also gives relative
measures on other considerations that people may take into account when making
decisions about their windows. The issue of "convenience" was broken down into
operability and maintenance. To some extent, longevity and reparability affects
convenience as well. The matrix evaluations aze generalizations and aze provided for
comparison purposes.
Staff heard conflicting input on the importance of cost and payback period (how long it
takes to recover the cost of a window improvement through energy bill savings). At least
two ad hoc panel members indicated that cost and payback period seem relatively
unimportant to owners of historic properties considering modifying their windows.
Others believe that the cost-effectiveness of a particulaz energy-efficiency improvement
should be a prime consideration. Additional cost information is found in Attachment H.
Input
Ad Hoc Panel Innut
The ad hoc panel was charged with information analysis and option development, but
they also were free to express their preference for a particular option. At their second/
final meeting, the panel indicated that they were leaning towazd Option B.
Panel members were asked at the public forum what key conclusions they'd drawn about
replac~ng vs. rehabilitating historic windows for energy-efficiency purposes. Common
themes in their responses are the following:
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,.
Decisions to allow replacement of historic windows should be made on a case by
case basis, because every house and window is different.
There are cases where historic windows should be required to be preserved.
Articulate these situations.
• S[orm windows are a good energy-efficiency option for historic windows.
Their individual comments are noted in Part 2 of Attachment E.
The panel's advice to eschew blanket rules and instead take a case-by-case approach
discredits Options A and C, which are de facto blanket rules. Option B is more "case-
based."
Public Input
Options and other project information were presented for input at the March 13 public
forum and on the project Web page. Almost 30 people attended the forum. The forum
included informal one-on-one discussions with staff and a formal Q& A session with the
panel. Eight people returned the comment form that was handed out. The forms show a
nearly even split in support of Option A or Option C. Only one favored Option B.
Another proposed an Option D, which would allow window replacements but be s[ricter
on solar panels.
Attachment I notes the questions and comments from the public during the forum Q& A
session and also includes written responses from the comment forms and submitted by
email and through the project Web site.
Staff Recommendation
Option regarding window replacement policy
The staff team, which includes the Office of Environmental Affairs, the Historic
Preservation Program, and Residential Pemut Review, favor the compromise offered by
Option B. This option is predominantly based on the historic significance of the
elevation where the windows are located. It acknowledges that every window has a
different historic context, and also provides flexibility for homeowners to replace some
windows for energy efficiency or other personal reasons. This option is based on the
finding that rehabilitating and retrofitting historic windows with a storm window or
second pane approaches the energy efficiency of a new double-pane window, but also
that new special window coatings, which are currently only recommended for new
insulated panes, can take energy efficiency a step further. From a broad environmental
perspective, the incremental energy difference is small between rehabilitating and
replacing historic windows on primary and some secondazy elevations, especially
considering [his would only apply to abou[ 2% of housing units city-wide (% of housing
units in city protected by Historic Preservation Ordinance). From an individual
environmental perspective, historic homeowners would have some restrictions on what
can be done to energy-upgrade their building, and that in some cases historic preservation
values take precedence. Homeowners would be encouraged to consider other, possibly
more effective and cost-effective ways to improve [he energy efficiency of their homes.
Option B would not be a radical departure from current practice in review and approval
of Landmark Alteration Certificates.
This option proposes treating historic doors the same as historic windows. Like
windows, doors can be chatacter-defining, especially on the primary elevation. Also, like
windows, they can be repaired, weather-stripped and retrofitted with a storm system for
improved energy conservation.
There have been few recent requests for Landmarks Alteration Certificates for solar
collectors, skylights or shutters on historic buildings. However, this could change as
energy prices rise and building technologies evolve. The main change under Option B
for solar collectors and skylights would be to allow them on the secondary elevation, not
just at the rear of the property or where inconspicuous, as is curtently required by the
historic preservation guidelines. The main change for shutters would be to allow them on
the secondary and tertiary elevations even when there is no historic precedent for
shutters. More flexibi-ity for piacement of solaz collectors, operable skylights and
shutters would give homeowners more energy conservation options, without damaging or
removing historic materials. The trade-off is a reduction in historic appearance on the
secondary and tertiary elevations.
The concept behind Option B is illustrated by the diagram on Attachment J. A flowchart
showing the decision-making procedure for Option B is shown by Attachment K.
Possible implementation for window/door alteration certificate applications is described
in Attachment L. One of the main disadvantages for this option is the extra level of
complication and uncertain[y caused by its basis in elevation hierarchy. It could add an
additiona] week to the current review/ approval timeline for a landmazk alteration
certificate. (For context, the total review/ approval timeline for a remodel or addition
project that requires a building pernut (which may or may not require Green Points), as
well as an alteration certificate, is about 6-10 weeks.)
Potential additional revisions
In addition to revising the Historic Preservation Guidelines to reflect the selected option
regarding window/door replacement and solaz/skylighUshutter placement> staff proposes
revising the Green Points Program and Historic Preservation Guidelines to address
specific project issues. Potential revisions aze summarized below and aze more fully
discussed with the project issues in Attachment M.
Green Points Revisions
Staff proposes adding point options for rehabilitating historic houses, windows and doors,
and also adding sections, notes, and sidebars to the Green Points Guidelines to clarify
where and how certain energy improvements should be applied to historic houses.
Potential revisions aze the following:
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- Add Point Options for:
Rehabilitating historic house
Storm windows and doors
Adding second interior pane to existing single-pane
Repairing, sealing and weather-stripping existing windows and doors
Donating historic building materials to salvage businesses
Operable shutters
- Add Section in Green Points Guidelines:
Historic Preservation - it complements Green Point Program intent to conserve
resources; - how to apply Green Points Program to historic buildings and
alteration certificate process
- Add Notes in Green Points Guidelines:
Solar collectors - caution regarding solar access code (neighbor may partially
shade) and possible structural roof changes; placement must comply with
historic guidelines and requires alteration certificate
Building overhangs and glazing for additions must comply with historic
guidelines
Use non-reflective glass on historic house
Replacement or modification of windows on historic house requires alteration
certificate
Replacement of siding on historic house requires alteration certificate
Replacement of roofing on historic house requires alteration certificate
- Add Sidebaz Information:
How to replace historic roofing materials (tile, slate)
Energy benefits of shades, blinds, curtains
Tax credits for historic rehabilitation
Historic Preservation Guideline Revisions
In addition to revisions reflecting the selected option regazding window replacement,
staff proposes adding sections to the Historic Preservation Guidelines to improve
understanding of Boulder's Historic Preservation Program, and also to educate and
encourage historic property owners to look for other ways to improve the energy
efficiency of their home besides replacing their historic windows.
Potentia] revisions include the following:
- Add Sections to Historic Preservation Guidelines:
Benefits and responsibilities of historic property ownership
Principles for evaluating historic resources, including windows
How to improve the energy efficiency of existing buildings (see Attachment N)
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List of allowable window treatment options with pros, cons and energy info
Where to find information/ regulations on tempered glazing, egress, lead and
asbestos hazards and abatement
- Amend Guidelines
More specificity about appropriate design and materials for replacement windows,
doors, siding, and roofs
How (revised) window/door guidelines apply to accessory buildings
Promote deconstruction rather than demolition; recycle and re-use materials
Project Process/ Timeline
The following table outlines the major remaining steps in completing and implementing
the Historic Preservation/ Environmental Sustainability Integration Project.
Joint meeting of EAB and April 26 Review project and staff
LPAB recommendation, discuss/ formulate
recommendation(s) to Cit Council
Separate LPAB and EAB LPAB May 3 Continue above, if needed
meetin s, if needed EAB Ma 10
City Council meeting June 6 Consideration of boazd
recommendation(s) and motion on
olic direction
On-going staff work with Regular monthly Review and adoption of revisions to
boards; separate board meetings as needed, Historic Preservation and Green
meetin s summer 2006 Points Pro am uidelines
On-going public process; Through 200b Review and adoption of revisions to
EAB, Planning Board and Green Points/ Resource
Cit Council meetin s Conservation Ordinance
Specific revisions to the Historic Preservation General Desigrt Guidelines and Green
Points Program would occur over summer 2006. This would entail the following
procedures:
• Historic Preservation Guidelines: adminisuative rules, revisions require
Landmazks Boazd approval
• Green Points Program: articulated in both the Green Points Guidelines and the
Resource Conservation Ordinance of the Boulder Revised Code
- Guideline revisions: administrative rules, Environmental Advisory Board
approval
- Ordinance changes: Planning Board and City Council approval.
Office of Environmental Affairs staff is revising the entire Green Points Program (not
just the portions that affect historic buildings). Prior to Planning Board review for
approval, OEA staff will ask the Landmazks Board to review and comment on specific,
proposed Green Points changes that relate to historic buildings. Likewise, Historic
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Preservation staff will ask the Environmental Advisory Board to review and comment on
specific, proposed changes to Historic Preservation guidelines that relate to
environmental sustainability.
~uestions for boards
Staff recommends the boards address the following questions at their Apri126 joint
meeting:
1) Do the boards support the approach outlined by Option B, regarding window and
door replacement and solar collector/skylighUshutter placement? Are any
changes suggested?
2) Do the boards support the approach outlined for additional revisions to the Green
Points and Historic Preservation guidelines (outlined under "Potential Additional
Revisions," p. 10-12):
- adding Green Point options for rehabilitating historic houses, windows
and doors, and adding information to the Green Points Guidelines
clarifying where and how certain energy improvements should be applied
to historic houses;
- adding information to the Historic Preservation Guidelines about the
principles, benefits and responsibilities of preserving his[oric buildings,
and about ways to improve the energy efficiency of historic buildings?
Requested action
Staff requests that each board make a motion to recommend a policy direction to City
Council regarding the issue of historic window replacement versus restoration, and
additional related revisions to the Historic Preservation and Green Points guidelines.
The two boards may adopt the same recommendation, or if there isn't agreement, may
adopt different policy recommendations. ff the boards decide they need more time for
discussion and decision-making, each may continue the item to their next monthly
meeting (LPAB May 3, EAB May 10), or could schedule an additional joint meeting.
Attachments
Attachment A: Other Cities' Policies on Historic Windows
Attachment B: City's Historic and Environmental Policies, Regulations and Guidelines
Attachment C: Findings & Facts
Attachment D: Window-Type U-Value and Energy Cost Comparison
Attachment E: Ad Hoc Panel at Public Forum
Attachment F: Photos of Solar Collectors and Shutters
Attachment G: Window Treatment Evaluation Matrix
Attachment H: Window Cost Information
Attachment I: Public Input - Q& A at Public Forum and Written Comments
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Attachment J: Diagram of Option B Concept
Attachment K: Decision-making Flowchart for Option B
Attachment L: Implementation of Option B
Attachment M: Project Issues and Proposed Resolutions/ Revisions
Attachment N: Energy Efficiency Improvements for Existing Buildings
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Attachment A
Other Cities' Policies on Historic Windows
Eugene. OR: Encourages homeowners to restore their windows rather than replace them,
with some success. The University of Oregon, city buildings and some homeowners
have been installing interior s[orms.
Ft Collins: Does not allow window removal without demonstrating need. If an applicant
proposes window removal, a detailed window survey must be performed with
photographs and documentation by a specialisUarchitect. Window repair is favored over
replacement, and the city frequently recommends people to two different window
repair/restoration companies near town. They have in the past allowed a few large
projects to replace the windows in the rear, while they preserved them on the fa~ade.
Norman, OK: Allows a like-for-like replacement, including true divided light. Staff
wishes it were different, but they have no way to change at this [ime. They did do a
workshop with their commission where [hey went to a window manufacturer to learn
how windows are made, and how just parts of a window can be replaced to help
encourage homeowners to repair rather than replace.
Provo, LTI': Allows replacement.
Santa Cruz, CA: Allows replacement as long as they are exact replicas, including true
divided light with wood. They encourage people to restore, but only one person has.
People seem to like the tilt back Marvin Windows.
Tempe, AZ: Area mostly has steel frame windows, so most homeowners replace.
Sometimes the street fa~ade is preserved.
Madison, WI: Each district has its own criteria; most will allow replacement with
modern materials, inciuding metal frames, as long as they are painted to look like wood.
In one district the criteria states they must restore the windows, and replacement is not
allowed there.
Denver: Discourages replacement; encourages repair and weatherizing. Replacement
considered if window beyond repair. Application must include detailed window survey
and evaluation of condition, with photos and drawings of existing windows and proposed
replacement windows. Replacements must be wood or metal-clad wood; no vinyl.
Breckenrid¢e, CO: Encourages preservation - rehabilitation or repair, with addition of
storm window or double-glazing.
Greelev, CO: Looks at each case. Preservation is first priority. Energy should not be
sole justification for replacement. Has allowed replacement of inetal casement windows
and rear windows with like-kind.
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Attachment B
City of Boulder Policies, Regulations and Guidelines Regarding
Historic Preservation and Environmental Sustainability
Council Goals
Environmental Goal: To enact and enhance city policies that will cause the
Boulder community to become a nationwide environmental leader among
communities. The City wil] be a role model of exemplary environmental
practices.
Boulder Valley Comprehensive Plan Policies (2005)
Community Design Section
Respect unique community identity
The community's unique identity and sense of place is in part characterized by its
history and should be respected by policy makers. (Policy 2.01)
Preserve historic resources
Building, districts and sites of historic, azchitectural, archeological, or cultural
significance shall be identified and protected. (233)
Coordinate with other goals/policies
Develop a Boulder Valley-wide preservation plan to ensure coordination between
preservation goals and zoning, land use, growth management, transportation and
housing goals, and ensure consistency among policies that affects the community's
historic resources (235)
Resource Conservation Section
• Limit use of non-renewable energy
Limit use of non-renewable energy resources by conserving energy and converting
to renewable resources. (Policy 439)
• Support conversion to renewable energy
Support private decisions to use renewable energy, develop local renewable energy
where economical, and preserve future options for renewable energy for when they
become cost effective. (439)
• Upgrade existing buildings
Continue efforts to improve energy-efficiency of existing buildings. Improve
codes, standards and regulations assuring energy and resource efficiency in new
construction, remodels and renovations. (4.41)
16
• Be sensitive to historic preservation
Energy conservation programs will be sensitive to historic preservation.
Encourage renovation of existing buildings over demolition. (4.41)
• Reduce waste
Support programs and activities that reduce the amount of waste that must be
landfilled; emphasize source reduction and reuse. Reduce solid waste produced in
the city by achieving 50% waste diversion by end of 2005. (4.42)
• Reuse materials
Develop policies and programs which promote the reuse of materials salvaged
after deconstruction in development and construction practices. (4A1)
• Favor low-waste products
Encourage use of products that are durable, repairable, reusable, recyclable, and
economically viable. (4.43)
Air Quality Section
• Reduce greenhouse gas emissions
Implement cost-effective actions that will reduce community's greenhouse gas
emissions. This requires integration of land use, building code, and energy supply
policies. (Policy 4.36)
Master Plans
Draft Waste Reduction Master Plan: 50% waste reduction
Upcoming Climate Action Plan: 7% greenhouse gas emissions reduction
Regulations (Ordinances)
Historic Preservation Ordinance
• Follow energy-efficiency policies
In reviewing applications for alterations to landmarks or structures in a historic
district, follow relevant city policies, including energy-efficient design (L.egislative
Intent, B.R.C. 10-13-1(c))
• Alteration applications may not be approved unless the proposed work...:
0 Preserves architecturalfeatures
...preserves and dces not damage the exterior architectural features of the property
0 Does not harm special interest or value
...does not adversely affect the special character or special historical, architectural,
or aesthetic interest or value of the landmark and its site or the district
17
Q Is compatible character-wise
Proposed architectural style, arrangement and materials are compatible with the
existing character (Standards for Landmark Alteration Applications, B.R.C. 10-13-
18(a-b(1-3))
• Consider economics and energy-efficiency
In reviewing alteration applications, consider economic feasibility of altematives
and incorporation of energy-efficient design (Standards for Landmark Alteration
App(ications, B.R.C. 10-13-18(c))
Resource Conservation - Green Points Ordinance
• Encourage cost-effective resource-conserving building methods
Ordinance purpose is to encourage cost-effective and sustainable residential
building methods to conserve fossil fue-s, water and other natural resources, to
promote the reuse and recycling of conswction materials, to reduce sotid waste,
and to promote enhanced indoor air quality. (B.R.C. 9-3.3-24(a))
• Points required for residential construction
0 Points requued for new residential construction, additions and interior remodels
Number of points required depends on project square footage (lazger project requires
more points).
0 Points aze awazded for use of resource-conserving materials and building practices.
Number of points awarded for a particular material or practice is commensurate with
its ]evel of resource conservation. (B.R.C. 9-3.3-24(a))
• Recycle construction waste
Point options for recycling construction waste, including clean wood. Painted or
treated wood not accepted. (B.R.C. 9-33-24(c)(4) and Green Points Guideline 1.2)
• Donate salvage materials
Point options for donating unused or salvaged materials, including windows and
doors, to organizations such as ReSource 2000. (B.R.C. 9-33-24(c)(2) and
Guideline 1.4)
• Use higher energy-efticiency windows and insulation
Point options for windows, insulation and other items that exceed the minimum
requirements of the Energy Conservation and Insulation Code (10-7). (B.R.C. 9-
3.3-24( fl and Guidelines p.4-5)
• Replace single-pane windows
Point options for replacing single-pane windows with double-glazed windows.
Lower U values yields more points. (B.R.C. 9-3.3-24(i)(5-7) and Guideline 6.2)
• Insulate walls
Point options for insulating wall cavities and exterior walls (9-3.3-"_'4(i)(9) and
Guidelines 63, 6.5, 6.9)
18
• Reduce air leakage
Point options for testing and reducing air infiitration rates by sealing exterior and
interior penetrations. (B.R.C. 9-33-24(j)(4) and Guideline 7.5)
• Use reflective windows
Point options for using reflective film or glass on east and west windows. (9-33-
24(j)(2) and Guideline 7.1.2)
• Useshadelandscaping
Point op[ions for landscaping that shades east and west windows. .(9-3.3-24(j)(2)
and Guideline 7.1.4)
• Provide window overhangs
Point options for providing south window overhangs. (9-3.3-24(j)(2) and
Guideline 7.1.5)
• Provide solar collectors
Point options for solaz collectors for hot water heating (Guideline 8.1), for space
heating (8.6) and for generating electricity (8.7), which must be mounted in an
appropriate (effective) location on the roof or ground and at an appropriate
(effective) angle. (9-33-24(k)(3) and (6))
• Provide south-wall glazing
Point options for glazing south wall to provide 20-60% of passive solaz space
heating of building. ((9-33-24(k)(2)(B-D)) and Guideline 8.4)
Energy Conservation Ordinance
• Building standards regulate energy conservation
Regulate building standards to minimize energy consumption for heating, cooling,
lighting, and ventilating and encourage passive solar heating. (10-7-1) 2000
International Energy Conservation Code adopted (with amendments) as City
standazd (B.R.C. 10-7-2)
• Plan for waste reuse and recycling required
A check list indicating waste reuse and recycling methods must be included in
compliance form for demolition, new construction and remodels/additions of
residential buildings greater than 500 square feet (B.R.C. 10-7-2(b))
• Only addition, not entire building, must comply
For additions to existing buildings, only the addition is required to comply with the
energy conservation code. (B.R.C. 10-7-2(d))
• Maximum U-factor allowed for replacement windows is 0.45
Replacement fenestra[ion products (where the entire unit, including the frame, sash
and glazing, is replaced) shall meet prescriptive fenestration U-factor criteria
(B.R.C. 10-7-2(d))
19
Maximum U-factors allowed for replacement solid and glazed doors
(B.R.C.10-7-2(dp
No limit on south wall glazing
No maximum azea limitation on the amount of glazing in south-facing walls.
provided the windows have operable insulated shutters or other devices to reduce
heat loss and are shaded from direct sunlight during cooling periods (B.R.C. 10-7-
2(k)(2p
Administrative Rules & Guidelines
Secretary of the Interior's Standards for Rehabilitation (adopted by
Landmarks Board 1990)
Avoid removal or alteration of historic materials or character-defining
features
Removal of historic materials or alteration of features that chazacterize a property
should be avoided. (Standazd 2, p.4)
Repair rather than replace
Deteriorated historic features should be repaired rather than replaced. (Standard 6)
Replacement should match original
Where the severity of deterioration requires replacement of a distinctive feature,
the new feature should match [he old in design, color, texture and, where possible,
materials. (Standazd 6)
Energy Retrofitting Section
• Use care in energy retrofitting
Retrofitting to make a historic building more energy efficient should be
carried out with particular caze to ensure historic character is preserved.
(Standazds p.28)
• Avoid water-content wall insulation
Applying urea of formaldehyde foam or other thermal insulation with water
content into wall cavities is not recommended. (p.28)
• Avoid incompatibie exterior wall insulation
Resurfacing historic building materials with more energy efficient but
incompatible materials, such as covering masonry with exterior insulation, is not
recommended (p.28)
• Avoid glazed passive solar walls where visible or damaging
Installing passive solu devices such as a glazed "trombe" wall on highly visible
elevations or where historical material must be removed or obswred is not
recommended. (p.28)
• Avoid water damage by storm windows
20
Interior s[orm windows [hat allow moisture to accumulate and damage [he window
are not recommended. (p.28)
• Avoid tinted or ret7ective glazing
Tinted or reflective glazing is not recommended on character-defining or
conspicuous facades. Use lighdy tinted glazing on non~haracter-defining facades
only if other energy-conservation alternatives aze not possible. (p.29)
Solar greenhouses should be carefully located
Solar greenhouse and other energy-conservation additions should be placed
on non-character-defining facades and should not obscure or damage
character-defining features. (p.29)
General Design Guidelines for Boulder's Historic Districts and Landmarks
Energy Efficiency Section
• Energy efficiency improvements should protect historic character
Ensure the energy efficiency concems aze addressed in ways that do not damage or
diminish the historic chazacter of the building, site or disu-ict. (General Guidelines,
Section Introduction 8.2)
• Preserve historic energy-conserving features
Retain and preserve [he hisroric, inherent energy-conserving features, including
shade trees, porches, operable windows, transoms, shutters and blinds. (8.2.1 and
8.2.3)
• Use traditional or appropriate means of increasing energy efficiency
Increase thermal efficiency by using traditional practices, such as weather stripping
and caulking, and by introducing appropriate energycfficient features, such as
storm windows and storm doors. (8.2.2)
Windows Section
• Windows important to character
Windows are one of the most important chuacter-defining elements of a historic
structure (Section Introduction 3.7)
• Publicly visible windows more important
Windows on facades visible from public streets, particularly the front fa~ade, are
especially important. (Introduction) Protection of front fagade windows may
supersede protection of windows elsewhere. (3.7.1)
• Poor window design damages character
Improper or insensitive treatme~t of windows can seriously detract from
architectural character of historic structure. (Introduction)
• Preserve windows
Windows should be preserved. (Introduction) Retain and preserve existing historic
windows, including their functional and decorative features, such as frames,
sashes, muntins, sills, heads, moldings, surrounds and hardware. (3.7.1)
• Repair rather than replace
21
Repair of historic windows is always preferred within a rehabilitation project.
Replacement should be considered only as a last resort. (Introduction) Repair
rather than replace the functional and decorative features of original windows
through recognized preservation methods. (3.7.3)
• Repairs for energy efficiency
Repairs can often improve energy efficiency of older windows (3.7.18).
• Storm windows, interior panels alternatives to replacement
Storm windows and interior energy panels aze altematives to replacement. Interior
installation and wood storm windows preferred. Metal storm windows may be
appropriate if frame proportions, profile and color matches original (3.7.18).
• Replace only deteriorated portion
If replacement of a feature is necessary, replace only the deteriorated feature in
kind rather than the entire unit (3J3) If sashes aze deteriorated beyond repair but
frames are salvageable,then only replace sashes (2.7.4)
• Match original
Replacement features should match materials, design and dimensions of original
(3.73). Replacement sashes should match original. (3.7.4). If repair infeasible,
replacement windows should match originals in size, materials, method of
operation and detailing (3.7.4).
• Wood replacement preferred, alternatives considered
Most appropriate to replace wood windows in kind; however, other material may
be considered if operation, dimensions, profile and finish similaz to original
(3.7.7).
• True-divided-light prefened
Most appropriate to replace we-divided-light windows in kind, matching original
dimensions, profile and detailing. High quality simulated-divided light windows
may be allowed if same muntin size as original. Snap-in muntins and other
inauthentic details inappropriate. (3.7.8)
• Use shutters only if appropriate
Use shutters only if appropriate to style of house; reintroduce shutters where
documented originals are missing. (3.7.15-16)
Doors
• Doors important to character
Front doors aze among most important elements of historic buildings. Original
size, proportion, placement, details and frame contribu[e to character. (Section 3.8
Introduction)
• Preserve doors
Retain and preserve original doors and openings (3.8.1) and their character-
defining features (3.8.2) and hardwaze (3.8.3)
• Repair rather than replace
Repair and restore damaged portions whenever possible. (3.8.4)
• Storm doors preferred
22
To improve energy conservation, consider storm door instead of replacement.
Wood storm doors most appropriate; metal may be appropriate if simple design
and baze me[al not visible. (3.8.7)
Match original
If replacement necessary, match original appearance and materials as closely as
possible.(3.8.5 and 3.8.9)
Roofs
Roof important to character
The roof is one of primary character-defining features of historic buildings.
Ensure roof alterations do not compromise historic integrity. (Section 3.1
Introduction)
Preserve original character
Historical roofing materials not required, but attempt to preserve type, unit scale
and texture of original roofing. In some cases, material type is important to
preserve, for example, metal and tile. Replace wood shingles with dimensional,
composition shingles. (3.1.2)
Retain and re-use details and trim
Retain and repair salvageable trim, brackets, comices, parapets, bargeboards,
gable-end shingles and other details. (3.1.2)
Solar Collectors
Location should be inconspicuous
Solaz collectors should not alter roof profile nor be highly visible, especially from
front of building. Mount collectors flush on reaz-facing roof or inconspicuously on
ground. (3.1.4) Not appropriate to locate them on characterdefining roofs or
where prominendy visible from street. (8.3.4) Collectors should be flat to pitch of
roof and located out of sight or on ground and not visible from street (Mapleton
Hill Guidelines V3.)
23
Attachment C
FINDINGS AND FACTS
rev. 3/10/06
Findings on Energy Efficiency of Windows
Staff and the project Ad Hoc Panel have made the following findings, based on the
studies and articles gathered and reviewed by staff and the panel (in Baseline Information
binder):
- Weatherization: Repairing, sealing and weather-stripping can greatly improve Ihe
energy efficiency of a leaky single-pane window. ~
- Single-pane vs. double-pane: Double-pane windows lose less heat than single-pane
windows and can keep a house cooler in the summer. At today's energy prices, an
average house in Boulder with single-pane windows would pay approximately
$150-$300 more annually for heating and cooling than a house with double-pane
windows.
- Retrofitted single-pane vs. double-pane: Rehabilitating a single-pane window and
adding a storm window or a second pane can result in energy-efficiency close to
that of a new double-pane window.
- Cost/Payback of new: Due to the relatively high cost of new windows, replacing
single-pane windows is rarely justified on the basis of energy cost savings alone.
Estimated payback period for new windows is usually several decades.
Additional Facts on Windows
The following facts also come into play in considering options for windows and were
discussed by staff and the Ad Hoc Panel.
- Other factors: Other reasons besides energy efficiency cited for repiacing old windows
relate to comfort, operability, condensation, safety, and maintenance.
- Comfort: Discomfort caused by radiant heat loss and drafts from windows is inversely
correlated with window energy-efficiency. In general, the better sealed and
insulated a window, the more comfortable it will be. A poorly sealed, un-insulated
~ Weatherizing an old window can include:
- squaring up the frame,
- repairing or replacing rotted parts,
- re-puttying joints between muntins and panes,
- caulking cracks in the frame,
- adding weather-stripping at vertical and horizontal joints on the sash,
- repairing or replacing the lock,
- insulating the rough opening between the frame and wall.
24
single-pane window will feel less comfoRable than a well-sealed double-pane
window or a well-sealed single-pane window with storm window.
- Maintenance: Wood windows require painting, whereas synthetic ones do not. Other
window maintenance is similar.
- Longevity and repair: New windows made with insulated glass and wood, vinyl- or
metal-clad wood, or viny] frame may not have the longevity of historic wood or
steel windows, and may be more difficult to repair:
- New windows usually are warrantied for 20 years or less; windows made 50
or more yeazs ago can be expected to last at least another 50 years if
maintained.
- Vinyl becomes brittle and cracks over time.
- Seals on insulated glass can break and allow condensation in 20-30 years.
- If a simulated divided-light pane breaks, the entire sash, not just the pane,
must be replaced.
- Newer woods are not as strong as 19~'- or eazly 20`h-century woods. Newer
locks and handles also tend not to be as durable.
- However, wood is more susceptible to moisture damage.
- Fiberglass windows have good life expec[ancy and seals, but few aze being
manufactured and their profiles are not as historic-looking.
- Storm window installation: If improperly installed, storm windows can cause
condensation and be difficult to operate. The inner-most pane must be sealed more
tightly than the outer pane to prevent condensation.
- Storm window operability: Some storm windows do not allow for operation of the
underlying window and therefore usually are changed seasonally; others do, and
therefore can stay in place year-round.
- Storm window cleaning: Storm windows may make window cleaning more difficult.
- Shutters: Automated operable shutters hold promise for high energy efficiency for
single- and double-pane windows, however they are not in widespread use. The
availability of models that would fit the character of Boulder's historic districts
needs more research.
- Glass/ sash replacement: If replacing original single-pane glass with new double-pane
glass, it may be advisable to consider replacing the sash instead. Although replacing
the sash would result in a greater loss of historic materials than replacing just the
panes, pane replacement can require so much work on the sash that it may render
the sash unstable, and if broken, the sash would most likely need to be replaced.
Due to the extent of the modifications required for pane replacement, it may make
sense to allow sash replacement to begin with.
- Skylights: Operable skylights offer not only day-lighting, but also therma] gain and
cooling/ ventilation. However, they also account for substantia] conductive losses
during hot periods in the summer and cold periods in the winter.
- Replicas: - Replacement windows that look similaz to historic windows are available.
However, in some cases, their materials, glazing, larger part size, and smaller
daylight opening make them recognizable as replicas.
- Permanent color: The color on clad windows can never be changed.
- Tempered glazing: Whether or not the glazing in an existing window is required by the
city building code to be replaced with tempered glazing depends on whether the
25
window is proposed to be altered and on the proposed window dimensions and
placement relative to nearby doors, stairways, and floor heights.
- Egress: The city building code may require modifications to doors and/or windows to
provide or improve egress if an existing building is re-modeled or expanded.
~ Hazardous materials: Any lead paint and asbestos hazards must be mitigated
according to Boulder County Health Department and state regulations, whether a
window is being restored or replaced. Windows that may or do have lead paint
should be kept painted-over or stripped of the lead paint according to established
procedures for lead paint removal, in order [o prevent paint chips or airbome lead
dust.
26
Attachment D
U-value and energy cost differences for different window types
Mattinson Efficient Kinney
W indows
Collaborative'
WINDOW TYPE U- House heating and Total house House heating
Value cooling attributed [o hea[ing and and cooling
of glass all windows cooling costs atvibuted to all
windows
Single pane window .98 $437 - poorly sealed $1591 $260
$389 - moderately sealed
$356 - ti hd sealed
Single pane + exterior storm .49 $257 - poorly sealed Na Similar to double-
$211 - moderately sealed pane clear (follow -
$176 - ti htl sealed u hone call, 2/06)
Double aneclear .5 $178-ti htl sealed $1427 $125
Double ane low-e as-filled 34-.4 $137 - ti htl sealed $1363 $40
Z What Should I Do About Mv Windows? Mattinson, Bill, Ross DePaola, and Dariush Arasteh.
Home Energy magazine. July-August 2002. Using RESFEN software for a 1,775 squaze-foot
existing house in Wisconsin with wood frame windows (224 square feet of window azea), gas
fumace and air conditioning in 2002.
3. Window Selection Tool, Efficient Windows Collaborative website, March 2006. Tool uses
RESF'EN software with Denver weather data and current energy rates for calculating annual
heating and cooling cosu for a 2,000 square-foot existing house with wood frame windows (300
square feet of window area), gas fumace and air conditioning.
° Glazine Analvsis for Historic Buildines. Jan. 30, 2006. Kinney, Larry. Using RESFEN
sofrware with Denver weather data and wrrent energy rates to calculate heating and cooling costs
of windows in a 2,000 square-foot house with tight wood frame windows (75 square feet of
window area on each of four elevations) and gas furnace.
27
Attachment E
Ad Hoc Panel Discussion at Public Forum
1) Key findings and facts for the available information?
Kristin Lewis:
- A lot can be done to make historic windows as energy efficient as new ones.
- Owners remodeling a historic home face strong forces to replace rather than repair their
windows: it's easier for the contractor to do, and there are warranties for new windows.
- To counteract this, there needs to be more education of homeowners about appreciating,
investing in, and having pride of ownership in their historic property. Also need more
education on what their options aze.
- Need to facilitate getting required number of Green Poin[s for historic home remodels.
Mazk Wernimont:
- The information binder for the project is one of the better assortments of pertinent
information.
- Most heat loss from windows is not through the glass, but is due to air filtration around
windows. There is usually a good deal of heat loss due to air leaks elsewhere in the
house, too.
- There aze options for rehabilitating historic windows that are very close to new
windows.
- Windows matter a great deal in imparting chazacter to a historic building.
- Need to accept that windows will never be as energy efficient as walls, but you
wouldn't want all walls. They're worth the sacrifice.
- The strongest motivating factors for people replacing windows are comfort and ease of
operation.
- The warranty for most new windows is 20 years. Warranties are important to
homeowners.
Victor Olgyay:
- No surprising information in the binder.
- Green Points is well defined, whereas historic preservation is more subjective.
Larry Kinney:
- Historic houses can be very energy wasteful - some due to windows, others not. The
higher the energy bills, the more room for improvement. Professional energy auditors
can help homeowners easily save 50% in energy in cost-effective ways.
- A lo[ of energy improvements can be made to the home's interior.
- Air filtration comes in at the bottom of the house and leaves through the top.
- Solar gain through windows is bad during the summer, but good during the winter.
- Temperature differential between inside and outside is [he key.
- Mistrust percentages of how much energy goes out a window - they can be very
misleading.
28
- It is possible to retrofit historic windows and aet aood results. Lots of labor is involved,
but doing it yourself is an option.
2) Key considerations and conclusions on replacing vs. rehabilitating historic
windows?
Kristin Lewis:
- Wood storm windows are a Qood solution, preferable to replacin~ the glass.
- There needs to be flexibility as to what is the important elevation of the building.
- Not every window must be saved. There should be a way to replace side and back
windows without much effort, but in the front, do not allow replications.
- Make decision on case by case basis.
Larry Kinney:
- I don't know "the" answer; mistrust anyone who claims to. Do not make blanket rules;
make decisions on a case by case basis, with replacement an option for the worst cases.
- There are storm windows with elegant glazing.
Victor Ol~yay:
- Determine when maintaining the historic artifact is more important than maintaining a
historic appearance. Sometimes a window's energy efficiency is not the most important
consideration, sometimes it is. How do we quantify that, make rules for so many
different cases?
Mark Wernimont:
- Blanket rules never work: There is no one solution that will fit every building.
Therefore, develop guidelines that ~ive the reasons as to when replacement or restoration
is appropriate. What are the situations?
- Need more education on why we do preservation
Note: Panel member Chris Koziol was not able to attend the public forum.
?9
Attachment F
Examples of Solar Collectors
~~11
30
Examples of Automated Shutters
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31
Att~-chment G- Evaluntion Matrix of Energy-Efficiency Window Treatment
Evaluation of energy-efficiency window treatments
~s energy consumption
ves histonc materials/ artifacts
ins histonc character/ appearance
~es occupant comfort
Low cost
condensation risk
ma intenance
poor fair better best
Key ~
Replacements should match material, design and dimensions of original as closely as possible.
Maintenace re(ers to seasonal change-out, painting, cleaning
Window Treatments
~`~~~
_ ~~r G `e~\c /
32
Attachment H
Approximate window costs and payback periods
Repair, Repair, Repair, Repair, Install Install New
Weather- Weather- Weather- Weather- New Window
strip strip strip strip Double- (sash and
Existina Existing Existing Existing Pane Sash frame)
Window Window> Window, Window,
Add Retrofit Install New
Siorm with 2"d Double
Window Pane Inside Glazing
Labor $17~ $190 $300 $360 $150-$??5 $200
Materials $~0 $280 $80 $180 $465 $780-$1110
Total $225 $470 $380 $540 $615-$690 $980- $1310
Payback Short Medium Short- Medium Med.ium- Long . ~
riad Medium I.on
Notes:
All windows are 3w2h/3w2h (3 lights wide by 2 lights high on upper sash and on lower
sash).
New window cost ranges from simulated divided-light (lower cost) to true divided-light
(higher cost). A new single-light window would be $605 materials ($805 total). A new
window with 2w2h/2w2h would be $720 materials ($920 total). New window may
require additional interior and exterior trim work, at $5-$7/linear foot, installed.
New sash cost rances from simulated divided-li~ht with insulated double pane (lower
cost) to true divided-light with second interior pane (higher cost).
Storm window is wood storm or storm/screen combination.
To save labor costs homeowner could do first, second or fifth column (repair, add storm
window, or replace sash); may need to hire help to do third, fourth or sixth column (add
2"`' pane, replace glazing or entire window).
Source: Mark Wernimont, Colorado Sash & Door, Inc.
33
Attachment I
Public Input
Pubtic Forum Q & A
1) What about the true costs of replacing windows, in terms of enerQy, labor, pollution,
subsidies, health care for workers, etc.? y
~ Mark Wernimont: We discussed this issue at lenjth and decided we couldn't
quantify it. We decided to focus on what we can quantify instead.
2) What are price differentials and payback periods for replacing versus retrofitting
windows?
• Kristin Lewis: Retrofitting has a lot of variables; that is the reason that contractors
prefer specifying new windows. The costs are ~enerally similar.
• Mark Wemimont: A window can be restored for the same or less than a new
window (except if it's only 1 or 2 windows - then price per window goes up).
The cost of a new true divided light window is typically more than restoring one.
The big~est energy improvement comes from adding a second pane or storm to a
single-pane window; there is less improvement in replacing the latter with a new
window.
3) Maybe pv panels should not be allowed on landmarks or more historic buildings.
Does the ad hoc panel have anything to say about solar panels?
• Larry Kinney: PV panels are only cost-effective if wasteful parts of the house
have been eliminated and appliances are high-efficiency.
Depends on which way is south and which is buildinj's primary elevation.
4) What should I do about my aluminum storm windows, which have to be changed twice
a year, which is especially difficult on the second floor? Don't storm windows just cover
up the historic windows?
Mark Wernimont: You can see still see wavy-ness of old glass from inside. You
could install a storm/ screen combination on the second floor, which can be left in
place and opened for ventilation in warm weather. Work on other ener~y
improvements in your house; do the best you can with your historic windows, but
keep them.
5) In one to two years, clear, hijh-performance glass with a suspended inner film of
silver will be availab~~ in new windows, which wil] offer better insulation than current
low-e coatina. Another emerging technology is fiberglass windows, which are very
strong, non-conductive, and paintable.
34
6) How long will it take applicant to go through window review process?
• James Hewat, Preservation staff: Now can usually go through process within a
week. Not sure about the future; depends on which approach is adopted.
7) The latest pv technology for roofing materials may have more aesthetic options than
the present reflective blue panels.
8) There's concem about total demolition of houses. In France, there are good-looking
replacement windows on historic buildings. Windows must be properly insulated before
storm windows aze put over them. Concemed that process to determine importance of
windows will be lengthy and expensive.
Comment Form Responses
Which of the three options do you favor? Why?
• Option A, preservation is a worthwhile priority. Upgrading energy
performance is more difficult, but is not precluded.
• Option A, historic is just that! I hate [he idea of different treatments for
different elevations. Keep the integtity of structure.
• Option A, windows are among the most important character- defining
features. You can determine style/ age of building primarily by looking at
windows. Issue of replica buildings versus historic buildings (e.g., Black
Hawk versus Boulder) - not just visual, it is truly measurable - is it
historic or new? Solution, it allows for improvement of energy efficiency,
yet still retains historic character. Don't need to look at other options if
this allows for energy efficiency for less money.
• Option A, those structures that have been determined important enough to
be designated as a landmark or historic district should refrain all of its
historic integrity and character.
• Option B, for increase efficiency maintaining looks - less embodied
energy use - exterior to local area.
• Option C, allowing greater flexibility in the process. The burdens on the
homeowner of an historic home are significant and other guidelines will
keep in check any significant "unhistoric" appeazance. The window frame
and glazing is only part of the project if a window needs upgrading.
• Option C, Old structures need complex and flexible solutions: solaz into
interior heat sinks and lightings; ease of window/ vent operation; structural
modification alcore/ weather cell/ mud room/ sun room; long-term
structure and materials survival; and structural modification for shadow
management an neighbors and yards.
• Option C, historic preservation is or should be primarily about
appearances. If there is no visible distinction from the street, we should be
focused on energy efficiency. Cleaz]y, tech solutions exist which can
35
reduce the waste. Energy efficiency should trump the "authenticity" of
historic preservation.
Option C, makes most sense. Good quality replacement windows look
excellent, save energy and add lifespan to buildin~.
How would you refine the options?
• For Option A, leave an out for people who absolutely can't rehabilitate
the windows due to condition.
~ 1, 2, and 3 under Option B- aren't these inherent in Sec. of Int.
S[andards? (i.e. wouldn't Option A allow for some replacement on reaz?)
Make sure what you are saving is historic! Define character - are there
some windows that are less important (bathroom windows)?
• Detemune who makes the decisions (i.e. survey to determine primary
elevation or replacements to replicate historic corridors.
• Actual evaluation of likely energy effect - if not much _, more
history _ looks.
• People ]ive in buildings and actively manipulate them on an hourly basis.
Criteria needed to allow more occupant discretion on design features. Big
item: improve use and management of solar radiation for light and heat
management. Include cost as factor.
• I like the idea of Option D- overall efficiency can be improved through
additional means. A point system for historic preservation with energy
efficiency in mind should be adopted.
Other comments
• Superb study by City staff.
• More education is needed [o inform the public about their historic homes
• In many houses the windows are not very significant in overall energy
use - more education
• Why are there no Green Points for storm windows, especially when they
are highly recommended in historic homes?
• Key is reconciled staff guidelines for a joint review that efficiendy
responds to permit request. The property owner faces many other issues
and does not need ambiguity in staff response.
• More important to locate PVi cells where [hey can operate efficiently -
new materials aze coming on line for better integrity with structure.
• Great presentation and discussion. Thank you.
• Imagine if we treated every[hing we own with this level of study.
• The current approval permit process is very heavily weighted toward
historic preservation with no real consideration given to environmental/
energy concerns. This leaves the homeowner in the position of having to
defend any changes motivated by energy concems to a completely hostile
crowd with no advocate on their side.
36
• Option A, pro is that most repairs will cost si~nificantly less than
replacement. Option C, "match as closely as possible" is too vague.
Option C, con - may (likely) jeopazdize city's CLG status.
. Re. additional facts (on yellow sheet): should discuss embodied energy in
historic windows and negative impact of new windows - why is there no
fact sheet on importance of historic preservation and why windows are
important. Other factors - not measurable and should not be included
(condensation not true). Comfort - any studies to prove this? Could add
the environmental cost of producing new glass windows. Add
affordability - most retrofit is cheaper.
• Add economic impact of preservation how rehab means more money to
local economy, rather than window replacement - order a window from
China.
• There was a question about the cost of the process - what is the cost of
the Green Points process?
• How is building construction waste measured?
• Joint sponsorship of this project - where is the money for this study
coming from? Should be jointly funded.
• Are there any other sustainability issues besides windows? Insulation,
enclosed porches, etc.
• There are always conflicts be[ween comp plan goals, is there recognition
here that historic pteservation has value? If so, then Option A allows for
improvement in energy efficiency, but still retains chazacter.
• Need to define "too deteriorated" for repair.
Comments Submitted by Email and through Project Web Site
(through 4/17/06; most recent first)
4/4/06
Comment_Question: I'm so glad this is being discussed.
1. Which of the 3 options do you favor and why?
I favor option 3.
We really do have to get serious about saving natural gas, electricity, air quality and etc,
folks.
Some of the extreme positions taken by historic preservation folks are making parody of
the process and their goals, eg Wayne Laugeson's fairly recent discussion of breaking old
windows in the Boulder Weekly. There must me some reasonable realm for change.
HOWEVER
I would favor option 2's in[ent to preserve historic exterior elevations in one case, which
would be ground leve] windows proximal to heavy pedestrian traffic, and proximal
37
means within 15 or 2o feet, not more than that; and an exception should be granted in
cases of extreme deterioration which means that a reputable restoration company could
not reasonably restore the window to full functionality while installing a basic heat mirror
unit and weather seais suitable to the wind exposure of the window(s) in question.
PS
I own [wo his[oric building in Boulder and have actually undertaken restoration of
windows myself. I'm willing to show others what was done. I share that it is possible,
albeit difficult, to put heat mirror panes into old windows. Three points of learnin~ are:
1) polyurethane caulk is a very durable way [o set window units and also strengthen the
whole assembly, but it is difficult to work with. 2) Window seals inside the units,
meaning the seal between panes of glass, can be protected from LTV with metal tape
usually applied in HVAC applications, and 3) Copper sash seals seem to work the best in
heavy wind applications, but are a bit tricky to install correctly.
2. How would you refine the option(s)?
See my response above. I think there should be this 2.5 level on the table, because of
course, since I'm suggesting it, I feel strongly i[ is the best course.
One possibility is for Historic Boulder to archive antique windows in good condition,
possibly working with Resource 2000, but this may be irrelevant because the realiy old
stuff was made on site, by hand, to whatever dimension was needed.
V aradaan
3/16/06
Thought you might be interested to know I posted on the meeting the other night.
h~://boulderrealtv.bloQSpot.com/2006/03/historic-windows-and-restoration.html
Best,
Osman Parvez
3/15/06
I think GHG and Boulder's interest in Kyoto concerns aze
both important issues.
In accounting GHG concerns it should be attempted to estimate
effects in a large perspective. I.e. if a bunch of stone needs
to be hauled in from Indiana to match some old stone the diesel
fuel and quarrying energy should be of concem.
When using woods which have a long growth time and are hauled a
]ong way special consideration should be given [e.g. redwood].
Recently in a Chinese river flood si[uation I hear the government
38
decided that a standing tree was worth 4 times more than a
cut tree in that area and prohibited further cutting.
We need to go deeper if we are going to succeed in some sustainabil~ty.
It has been, and still is, convenient to ignore secondazy and
tertiazy effects of various actions in building and materials use.
The time lags are long for GHG considerations and it is hard but
not impossible to estimate the effect of GHG effects from immediate
embodied energy considerations versus offset GHG future emissions
from improved windows, insulation and so forth. I expect there has
been work done on this sort of consideration but likely the building
industry is not so interested as it may be that various materials
and processes should not be used/done.
The situation is complex and the fact that we are becoming more
interested is good... I hope the national government gets more
interested too!
These considerations are important for all building and building a
new 5000 SF house with efficient insulation is often worse than an
old house of older material & smaller size - both because of new
emodied energy use which caused GHG emissions and larger azeas
to leak heat etc., .
good luck with it all!
Premena
3/7/2006
As i see it, historic preservation is quite important. But it can be
accomplished in a number of ways other than a"don't touch it" approach.
Photography & written documentation should be a good start. In
particular, i think it's imperative to consult (ASAP) with regional elders
who might be able to comment on the significance of historic structures &
other matters. They are a resouce [hat --as is the case for all of us--
won't always be available.
'Moving toward and through the evolving energy crisis, if historically
significant structures are to be even remotely usable, they will almost
surely need to be re[rofited for longer-term sustainability.
'Just my $0.02. Thanks for your consideration.
pax,
Karl Hanzel
39
3/7/2006
As professionals practicing in preservation, we have successfully retrofitted windows, at
less cost, and yielding greater energy efficiency, than replacement windows. AS you
probably know, the greatest energy loss is azound the window assembly, not through the
glass itself. The savings yielded from thermopane glass itself is minimal. We also have
successfully used local labor for weather stripping and reglazing, which keeps more
dollars in the local economy. We've also used new storm windows, which are inserted
from the inside, to achieve much greater insulation value than a double glazed window
assembly.
The National Trus[ published an excellent book about energy conservation in older
buildings some 20 years ago, which may no longer be in print, but the latest issue of the
APT Bulletin, the Journal of Preservation Technology, has an excellent article about
energy conservation and sustainability with respect to windows. It points out that the
embodied energy in an existing window assembly needs to be taken into consideration, as
well as the operating costs. I you do not have access to this article, please contact Betsy
in my office and we will fax it to you.
Nore Winter
Winter & Company
40
Attachment J-Diagram of Option B Concep[
(
~_~ ~
; 1.4a r.. :~ ~? - - -
C~+b -~
7ertiary elevation -~ ' s
~ ~
~ Secondary
~ -elevation ,
t~
r"`
~
Primary elevation
~..
~._---_,--- ~_---'-
~
t „F s, y~ t,E ~-,.
~ ~f _ - - ...._ _
~ ._ ~ l.._.r~
, r ~ ~ _. -
_. - --}
~
1
~
``
~
~ ~~
~ r~• ~
,..
z4•z _ __._~ -,. _---
_ ~~ J, _
~
~
t~ ~ 4 t a' , S V
~~~
- Visible from street
by Panel Member Chris Koziol 41
Attachment K- Decision-making flowchart for Option B
OPTION B: POTENTIAL WINDOIN (& DO~R) REPLACEMENT POLICY
Buildings Protected by
H.P Ordinance
Non- Contributing
Replacement
OK
Window/Door Not Historic
Replacement
OK
Replacement OK:
-Entire window or
aoor
•Wlndow sash only
•If muntins, replace
single pane w!
Insulated glass unit
Rehabilitate:
-Repafr or replace broken, rotten or missing parts
-Seal & weather-sfip
Retrofit (for Energy Conservation):
-Add storm wlndow/door
-Add second interior pone
-If no muntins, replace single-pane wl fnsulated glass
Landmarks &
Contributing
Window/ Door Historic
Deteriorated Beyond '
Repnir (rare)
Replacement
OK
Tertiary Facade
Replacement
OK
Deteriorated
Repair
Secondary Facade
Not Visible From Street ar
Alley
Replacement
OK
Primary Facade
Visible irom Street or
Alley
Rehabilitate/
Retrofit
Rehabilitate/
Retrofit
Attachment K- Decision-making flowchart for Qption B
OPTION B: PQTENTIAI WIND~IN (& DOOR) REPLACEMENT POLICY
Buildings Protected by
H.P Ordinance
Non- Contributing
Replacement
OK
Window/Door Not Historic
Replacement
OK
~~..w~
Replacement OK:
-Enflre window or
aoo~
-Wi~dow sash only
-If mun~ns, replace
~ngle pane w1
insulated glass unit
-Repair or replace broken, rotten or missing parfs
-Seal & weather-sfip
Retrofit (for Energy Conservation):
-Add storm window/door
-Add second interior pane
~
•If no munBns, replace single-pane w/ insulated glass
landmarks &
Contributing
Dete~orated Beyond
Repair (rare)
Replacement
OK
Tertiary Facade
~ ~
Replacement
OK
Window/
Not Deteriorated Beyond
R~pair
J Secondary Facade Primary Facade
Rehabilitate/
'~ ~ Retrofit
.
~t Visibie From Street or Visible i~om Street or
,
Alley Alley ~~
Replacement
OK
Rehabilitate/
Retrofit
~
Attachment L
Possible Implementation of Option B
The following outlines how Option B might work for window and door alteration
certificate applications. This detail is provided because the some members of the public
and several board members inquired about the effects that the recommended option might
have on alteration certi£cate review/approval process length, difficulty, clarity, certainty
and cost. (This does not include the procedure for obtaining a building permit. The
timeline for ob[aining a building pernut, with or without a Green Point requirement, and a
landmazk alteration certificate is approximately 6-10 weeks.)
Summary:
Option B considers the question of replacement vs. rehabilitation of historic windows and
doors on a case by case basis, mainly on the basis of the historic significance and the
visibility of the window or door.
Window/ door re.placement allowed:
- Non-contributing buildings in historic districts
- Non-historic windows/ doors
- Historic windows/ doors on landmark and contributing buildings that are
deteriorated beyond repair
- Historic windows/ doors on tertiary elevations of landmatk and contributing
buildings
- Historic windows/ doors not visible from the street that are on secondary
elevations of landmazks and contributing buildings
Window/ door replacement not allowed:
- Historic windows/ doors on primary elevations of landmarks and contributing
buildings
- Historic windows/ doors visible from the street that are on secondary elevations of
landmazks and contributing buildings
Procedure:
1. Deternvne whether building is a landmazk, contributing or non-contributing:
Check-in with staff
Applicant action: Phone call or email to staff
Timeframe: 1 day - 3 days (or immediately online for landmazk check)
Decision: If non-contributing, replacement allowed
If landmazk or contributing, continue to step 2
If landmazk or contributing, deternvne whether windows/doors are historic or not:
Site visit by staff
Applicant action: Request staff site visit by phone or email
Timeframe: one week
43
Criteria: Is window 50 years older or more?
Does window impart historic character to the building?
Does window exhibit special characteristics or high level
of craftsmanship?
Decision: If non-historic, replacement aliowed.
If historic, continue to step 3
3. Determine whether historic windows/doors are deteriorated beyond repair: Window
condition evaluation
Applicant action: Fill-out and submit evaluation form with photos, review
with staff, staff visit if evaluation form is
inconclusive.
Timeframe: one week
Criteria: If 30% or more of the non-glass area is inepazable, it is
considered deteriorated beyond repair. (This is raze due to
our dry climate; most often damage can be repaired.)
Decision: If deteriorated by repair, replacement allowed
If not deteriorated, continue to step 4
4. Determine which elevation windows/doors are located on:
Elevation and visibility determination
Applicant action: Request staff site visit by phone or email
Timeframe: one week
Criteria for primary/ secondazy/ tertiary elevation determination:
- Primary elevation - usually front of building; has most important
chazacter-defining architectural elements, such as windows, door,
window frames, porch, brackets, etc.; faces street (except on rare
occasion)
- Secondazy elevation - sides of building; generally has fewer
character-defining azchitectural elements; may or may not be visible
from street or alley
-Tertiary elevation - back of building; usually has few if any
character-defining azchitectural elements; not visible from street,
may be visible from alley
Criteria for visibility of secondary elevation:
- Visibility from street during winter! baze-branch season. During
in-leaf season, staff will need to estimate extent of visibility during
winter. Temporary barriers or construction aze not considered in
visibility test. Part of secondary elevation may be visible and part
may not.
Decision:
If window/door on tertiary elevation, replacement allowed.
44
If window/door on secondary elevation and not visible from street,
replacement allowed.
If window/door on primary elevation, it should be rehabilitated
and/or energy-retrofitted, rather than replaced.
If window/door on secondary elevation and visible from street, it
should be rehabilitated andlor energy-retrofitted, rather than
replaced. This could include:
- Sealing air leaks, weather stripping, making repairs
- Adding a storm window/ door, second interior pane,
replacing the single panes with insulated glass units if no muntins.
5. Approvai for altering or replacing windows:
Alteration Certificate
Applicant action: Sign-up for design review committee review by phone
or email, submit alteration certificate application and supporting
materials day before design review committee weekly meeting
Timeframe: one week
Any of the above steps can be combined. Timeline for all steps would be
approximately 1- 2 weeks. No fees aze proposed for any of the steps.
45
Attachment M
Project Issues and Potential Resolutions/ Revisions
Issue 1: Historic preservation is not well understood.
The City needs to better educate property owners and building professionals on xhe
existence of the Historic Preservation Program, its rationale and benefits, and the
responsibi(ities entailed in stewardship of historic resources.
Potential Resolutions:
Add section to Histonc Preservation Guidelines on benefits and responsibilities of
historic property ownership.
Add section to Green Points Guidelines about Historic Preservation Program, izs
goals and principles, and how its alieration cenificate process works wiih the
Green Points Program.
• I,ook for other ways to educate public, including prospective buyers of designated
historic properties, about Historic Preservation Program.
Issue 2: When alterations are considered, it is not clear how windows and other
historic elements are evaluated from the historic preservation perspective.
Clarity is needed regarding the:
- Rationale for favoring conservation of original artifacts over replication of
artifacts
- Relative importance of preserving all original artifacts versus preserving only
those most visible to the public
- Values assigned to windows: from different periods; of different materials (wood,
metal); on different parts of the building (front elevation, alley, etc.); in different
conditions
- Values assigned to different parts of a window (frame, glass, muntins, hardware,
etc.)
- Circumstances under which various alterations are approved or denied, including
those involving glass safety and egress code requirements.
Analysis: Safery Concerns
The issue of replacing or modifying existing windows for safety reasons is handled by the
building code. The question of whether old glaz~ng must be replaced with tempered glass
is specified by Section R308 of the ciry-adoPted International Residential Code and
depends on the proposed dimensions of the window in question and its proposed location
relative to nearby doors, stairrvays and floor heights. Any requirement to install tempered
glazing overrides the historic design guidelines. However, this happens infrequently, and
somefimes property owners wish to replace historic glazing with tempered glazing even
though it is not required by code. In those cases, the historic design guideiines would
apply to the decision to allow replacement.
46
4Vi~ulows can provide emergency egress. Wl1en an existing building is re-modeled or
expanded, the ciry building code may require modificatioris to windows and/or doors [o
provide or improve egress. In these cases, the building code takes precedence over the
historic design guidelines.
Some historic windows have old layers of lead-based paint that are hazardous if the paint
is chipping or being ground into airborne dust by window operation. This can be
mitigated by keeping the lead-paint layer painted over or by stripping the lead-paint layer
according to established procedures. Some histonc houses also have asbestos,
panicularly in the insulation, which may become hazardous if it is disturbed when
removing window or door frames. As with lead paint, asbestos should be mitigated
according Boulder Counry Health Deparhnent and state regulations. Lead and asbestos
hazards can arise whether a window or door is being restored or replaced, and can be
mitigated in either case.
Potential Resolutions:
Add section to Historic Preservation Guidelines on principles for evaluating
historic resources, induding windows.
• Create separate section in Historic Preservation on where to find
information/regulations on tempered glazing, egress, lead and asbestos hazards
and abatement.
Issue 3: Historic Preservation Program offers limited guidance on improving energy
efficiency of older buildings.
The Historic Preservation ordinance and guidelines conceptually support energy-efficiency
design and upgrades, but offer limited information on how owners can improve the energy
efficiency of their old buildings without damaging historic character. More information is
needed on acceptab3e energy improvement options and their advantages and disadvantages,
including lead paint and asbestos abatement.
Potential Resolutions:
• Create separate, expanded section on Energy Efficiency (currently shon subsection
in "Miscellaneous" chapter) in Historic Design Guidelines and include annotated
list of energy efficiency improvements typically recommended for existing buildings
(see draft list in Atrachment N). Note which improvements affect exterior and
therefore may be subject to guidelines and alteration certiftcate requirement.
Under Windows section, include range of allowable window treatment options wirh
pros, cons and general energy conservation effects.
Issue 4: The Historic Preservation Guidelines may prevent certain energy-efficiency
upgrades.
The Historic Preservation Guidelines (which apply to any exterior alteration or addition to
a historic building and to any new building in a historic district) prescribe certain practices
47
that may hamper owners' efforts to improve energy efficiency and/or that may limit Green
Points awazd options:
- Restore rather than replace historic (single-pane) windows; replace only
when severely deteriorated
- Any replacement windows and doors must meet specific design parameters
- Add a storm door rather than replace a historic door
- Do not use reflective films or glass in windows
- Install shutters only where historical precedent
- Do not install window overhangs where incompatible with historic
chazacter
- Number and size of windows should be determined by his[oric character,
not solar benefit
- Place solaz panels or solar greenhouse where inconspicuous, not necessarily
where solar access
- Porch enclosures should be transpazent and not have solid walls
- Roofing should conform to historic proportions and not be reflective
Analysis:
Non-reflective window coatings are now avai[able to control solar heat gain, so there is no
longer a need for reflective films or glass from an energy standpoint.
Enclosing a porch is regulated by the building code, energy code and land use regulations.
These factors will supersede the historic preservarion guideline on transparency/ solid
walls.
Potential Resolutions:
• Revise guidelines regarding windows, storm windows and doors, solar collector
placement, shutters and sky[ights according to option selection.
• Under Windows section, add specificiry acceptable design and materials for
replacement windows and new shuiters. Same with replacement doors.
• Do not revise guide[ines regarding reflective films, roofs or porch enclosures.
Issue 5: Certain Green Point award options may damage historic character.
The Green Points Program awards (but does not require) points for certain building
materials and practices that may not be compatible with Historic Preservation Guidelines:
- Replacing single-pane windows
- Insulating exterior of exterior walls
- Providing glazing on the south elevation for passive solar gain
- Adding solar panels designed to maximize solar benefit
- Using reflective films or giass in windows
- Installing overhangs on south windows
Analysis:
48
Historic laomeowners are likely to add south elevation glazing only on an addition, and
additions usually happen in the rear, so this Green Point is not ezpected ro be a problem
for historic propenies.
Potential Resolutions:
• Add note to Green Points on solar collecmrs, overhangs, solar glazing and single-
pane replacentents that for designated historic Propenies, points are available only
for changes consistent with (revised) Historic Preservation Guidelines and
approved through Landmark Alteration Cenifica[e process.
Eliminate Green Points for insulating extenor of exterior walls and for using
reflective films and glass, whether historic building or not (pan of overall Green
Points Revision Project).
Issue 6: Green Points may overlook some mutually bene6cial practices.
Green Points are not offered for certain practices that may serve both environmental and
historic preservation goals:
- Restoring rather than discarding old windows
- Adding storm windows and doors rather than discarding old windows and
doors
- Restoring rather than replacing old roofing
- Conserving existing walls
- Conserving historic cooling measures - porches, shades and blinds,
shutters,trees
- Donating historic materials to for-profit businesses specializing in historic
salvage
It can be more difficult to eam the required number of Green Points when remodeling a
historic structure, due to the need to balance many factors.
Analysis:
Awarding Green Points for elements homeowners do not remove, such as walls and
windows, would be difficult to administer and could skew the point award system.
Poiential Resolutions:
• Add Green Points for rehabilitating historic buildings according to tax credir
rehabilitation standards.
• Add Green Points for installing storm windows and doors, adding a second pane to
an existing single-pane window, installing operable shutters, repairing, sealing and
weather-stnpping existing windows and doors, and donating historic materials to
for-profit businesses (in addition to non-profits).
• Add sidebars on restoring historic roofs and the energy benefits of shades, blinds
and cunains.
• Keep sidebar on natural cooling effect of trees.
49
Issue 7: Green Points Program is not specitic about its appiication to historic
buildings.
The Green Points Program can affect historic buildings, but the program ordinance and
guidelines do not specify the extent to which the program applies to historic buildings or
how i[ works in conjunction with His[oric Preservation regula[ions, guidelines, and review
processes.
Potential Resolution:
Add section to Green Points Guidelines about Historic Preservation Program, its
goals and principles, and how its alteration cenificate process works with the
Green Points Program.
Issue S: Relative priority of other window considerations is not clear.
Other considerations besides energy efficiency and historic value enter into the question of
whether to retain or replace historic windows. These include cost, investment payback
time, occupant discomfort due to radiant heat loss and drafts, condensation, noise
abatemenU sound insulation, ease of use, longevity, maintenance, aesthetics, and protection
from ultra-violet fading. To what extent should these various considerations be factored
into changes to the Green Poinis Program andlor Historic Preservation Guidelines
regarding window replacement? (To some extent they already are factored into Green
Points Program in that applicants can pick and choose award options based on their own
priorities, which may include any of the above considerations.)
Analysis:
Occupant comfon and sound insulation go hand in hand wirh energy efficiency: the better
insulated and sealed a window is, the more comfort and quiet the occupant will
expenence. Table 1 in Mattinson anicle, "What Should I Do About My Windows?, "
shows inside surface glass temperature - which iranslates to radiant heat loss - for
different window rypes.
The importance of cost and payback period vanes greatly among individuals - for some,
this is a major consideration, for others it isn't. Aesthetic judgments (wavy-ness of old
glass, "old- looking" windows in a newly remodeled house, etc.) also vary greatly among
individuals.
Condensation is not a serious problem in this dry climate and can be mitigated by proper
installation of storm windows.
With proper maintenance and repair, old windows can be made fuUy operable. Operable
storm windows are available.
Maintenance is considered pan and parcel owning of a historic building, and
owners/buyers of historic houses should be prepared to deal with the extra ntaintenance
sometimes required with older buildings.
Although the anticipated lifespan of different window types does vary and can affect the
wasre stream, it seems inappropriate to prohibit cenain types of windows based on their
projected lifespan.
Few people expressed concern about uv fading.
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Potential Resolutions:
Base policy on window replacement vs. restoration pnmarily o~i energy efficiency
and historic value. Policy should reflect a compromise beiween improving energy
efficiency and preserving historic materiaG It should allow measures that could
significantly improve energy efficiency but still preserve historic materials.
Measures that could offer even better energy efficiency but would damage or
remove historic materials could allowed on less historically significant and less
visible windows.
Information on the other considerations should be provided under the pros and
cons of allowed measures, but should not be the basis for allowing or prohibiting
historic window replacement.
Issue 9: How could the Historic Preservation Program contribute to the city's other
environmental efforts?
Is there a role for the Historic Preservation Program in the city's efforts to reduce and
recycle construction waste, as put forth by the Waste Management Plan? Could historic
preservation have any notable effect on the city's efforts to reduce greenhouse gas
emissions, to be set forth in a Climate Action Plan?
Analysis:
20% - 25% of landfill capacity is consumed by construction and demolition waste. The
Draft Waste Reduction Master Plan focuses on increasing recycling and re-use of
construction materials, not on conserving buildings to prevent waste production.
Historic preservation does not have a notable effect on the city-wide greenhouse gas
emission efforts, panicularly in comparison to other factors/ possible actions related to
greenhouse gases.
Potential Resolutions:
Do not add historic preservation element to either Waste Management Plan or
Climate Action Plan.
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Attachment N
Improving the Energy Efficiency of Existing Buildings
Replacing old, single-pane windows is one of many possible ways to improve the energy
efficiency of existing buildings. Others include:
- Insulating the attic.
- Sealing air leaks around floor/wall seams, ducts, electrical and plumbing
penetrations, chimneys and fireplaces, recessed lighting, spaces behind cupboards
and closets, doors and windows.
- Insulating walls.
- Insulating the basement or crawl space.
- Insulating ducts, pipes, and water heater.
- Installing compact fluorescent bulbs.
- Installing storm windows.
- Replacing an old furnace with a new one, or having it tunec.
- Installing Energy-Star appliances and low-flow shower heads.
- Converting conventional cooling to evaporative cooling or whole-house fan.
The best way to understand which upgrades will offer the best retum for an individual
building is by having a professional energy audit of the building.
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