Summary

Advanced Energy Efficient Window Films

Double-pane Window Glazing: Low-E Film vs. No film

Window films that can be applied to older single-pane windows as an alternative to replacement with new double-pane windows.

Synopsis:

Window films are an after-market retrofit option historically designed to solve problems with excessive heat gain or glare from an existing window. While window films have been available for over 40 years, recent advances in film quality and the introduction of low-emissivity (Low-E) films offer improved performance in heating-dominated climates. The latest films also have a much higher visible light transmittance and thus can be used in the often rainy Northwest without resulting in gloomy interiors. While this is a non-energy benefit and doesn't improve energy savings, it facilitates a greater adoption rate of this technology, which is why this is included as an emerging technology. These improvements have renewed interest in the technology as an alternative to total window replacement.

Low-E films improve window-insulating performance by reducing the window U-Factor (increasing window R-Value). The Low-E coating of these films helps reduce the loss of heat during the heating season. Films with Low-E and high visible transmittance (VT) offer the desired winter heat-loss reduction of Low-E films but also pass visible light into the building, preserving views and eliminating the gloom often associated with conventional Low-E products with low solar heat gain coefficient (SHGC) features.
Paybacks for residential applications with single-pane, wood-framed windows exceeds 95 years in Seattle and 30 in Spokane, Boise, and Kalispell. Commercial paybacks in Seattle exceed 36 years, although heating cooling load reduction is about 40%.

Energy Savings: 4%

Energy Savings Rating: Not rated. What's this?

Level	Status	Description
1	Concept not validated	Claims of energy savings may not be credible due to lack of documentation or validation by unbiased experts.
2	Concept validated:	An unbiased expert has validated efficiency concepts through technical review and calculations based on engineering principles.
3	Limited assessment	An unbiased expert has measured technology characteristics and factors of energy use through one or more tests in typical applications with a clear baseline.
4	Extensive assessment	Additional testing in relevant applications and environments has increased knowledge of performance across a broad range of products, applications, and system conditions.
5	Comprehensive analysis	Results of lab and field tests have been used to develop methods for reliable prediction of performance across the range of intended applications.
6	Approved measure	Protocols for technology application are established and approved.

Simple Payback, New Construction (years): 33.8 What's this?

Simple Payback, Retrofit (years): 33.8 What's this?

Simple Payback is one tool used to estimate the cost-effectiveness of a proposed investment, such as the investment in an energy efficient technology. Simple payback indicates how many years it will take for the initial investment to "pay itself back." The basic formula for calculating a simple payback is:

Simple Payback = Incremental First Cost / Annual Savings

The Incremental Cost is determined by subtracting the Baseline First Cost from the Measure First Cost.

For New Construction, the Baseline First Cost is the cost to purchase the standard practice technology. The Measure First Cost is the cost of the alternative, more energy efficienct technology. Installation costs are not included, as it is assumed that installation costs are approximately the same for the Baseline and the Emerging Technology.

For Retrofit scenarios, the Baseline First Cost is $0, since the baseline scenario is to leave the existing equipment in place. The Emerging Technology First Cost is the Measure First Cost plus Installation Cost (the cost of the replacement technology, plus the labor cost to install it). Retrofit scenarios generally have a higher First Cost and longer Simple Paybacks than New Construction scenarios.

Simple Paybacks are called "simple" because they do not include details such as the time value of money or inflation, and often do not include operations and maintenance (O&M) costs or end-of-life disposal costs. However, they can still provide a powerful tool for a quick assessment of a proposed measure. These paybacks are rough estimates based upon best available data, and should be treated with caution. For major financial decisions, it is suggested that a full Lifecycle Cost Analysis be performed which includes the unique details of your situation.

The energy savings estimates are based upon an electric rate of $.09/kWh, and are calculated by comparing the range of estimated energy savings to the baseline energy use. For most technologies, this results in "Typical," "Fast" and "Slow" payback estimates, corresponding with the "Typical," "High" and "Low" estimates of energy savings, respectively.

Details

Advanced Energy Efficient Window Films

Double-pane Window Glazing: Low-E Film vs. No film

Window films that can be applied to older single-pane windows as an alternative to replacement with new double-pane windows.

Item ID: 475

Sector: Residential, Commercial

Energy System: Building Envelope--Windows & Skylights

Synopsis:

Baseline Example:

Baseline Description: Single Pane, Wood-Framed Clear Glass to Low-E
Baseline Energy Use: 19125 kWh per year per house

Comments:

The baseline annual energy use is for a 2000 sf single-story building equipped with baseline windows and located in Boise, Idaho. Low-E film energy savings are much less in the Seattle, WA area. Heating and cooling loads are computed with the LBNL RESFEN model and are based upon a total window area equal to 15% of the floor area, windows equally distributed in all orientations, and with heat pump heating and cooling. Thermostat settings are 70 deg F in the heating season and 78 deg F in the cooling season. A heating night setback of 65 deg F is also assumed. Typical infiltration and solar heat gain reductions were assumed.

Manufacturer's Energy Savings Claims: Currently no data available.

Best Estimate of Energy Savings:

"Typical" Savings: 4%
Low and High Energy Savings: 1% to 4%

Comments:

Energy savings benefits due to window film retrofits are expected to vary widely based on the baseline window design, with the greatest savings resulting from retrofitting existing single-pane windows. Energy savings also depend on performance of the film employed; local climate; building orientation; window-to-wall ratio (in each direction); the presence of shading produced by vegetation, other buildings, overhangs, fins, or awnings; building heating and cooling temperature setpoints and setbacks; use of economizers or operable windows; and the type and overall efficiency of HVAC system.

Simple paybacks for Low-E window film retrofits on single-pane, wood-framed windows exceed 95 years in western Washington – longer than the 30-year payback when the same film is applied to glazing in sunny Spokane, Boise, and Kalispell. Energy savings for residential heating and cooling range from 1.2% in Seattle to 4.3% in Boise (from Gilbert McCoy, WSU Energy Program, "Residential and Commercial Sector Window Film Retrofits in the Pacific Northwest", for BPA E3T Program, June, 2013).

Energy Use of Emerging Technology:

18,360 kWh per house per year What's this?

Energy Use of an Emerging Technology is based upon the following algorithm.

Baseline Energy Use - (Baseline Energy Use * Best Estimate of Energy Savings (either Typical savings OR the high range of savings.))

Technical Potential:
Units: house
Potential number of units replaced by this technology: 171,039
Comments:

Houses with single-glazed metal or wood/vinyl/fiberglass frames account for about 12% of the regional stock (Ecotope, "2011 Residential Building Stock Assessment: Single Family Characteristics and Energy Use", for NEEA, September, 2012, Page 43). Furthermore, there are approximately 1,452,328 houses (or 36% of the regional total) in Idaho, Western Montana, Eastern Oregon, and Eastern Washington. The total number of houses that are suitable candidates for Low-E or advanced window films is estimated at: 0.12 x 1,425,328 = 171,039.

Regional Technical Potential:
0.13 TWh per year
15 aMW
What's this?

Regional Technical Potential of an Emerging Technology is calculated as follows:

Baseline Energy Use * Estimate of Energy Savings (either Typical savings OR the high range of savings) * Technical Potential (potential number of units replaced by the Emerging Technology)

First Cost:

Installed first cost per: house
Emerging Technology Unit Cost (Equipment Only): $2325.00
Emerging Technology Installation Cost (Labor, Disposal, Etc.): $0.01
Baseline Technology Unit Cost (Equipment Only): $0.01

Comments:

Reflective window films have been available since 1965. Use of these basic reflective and absorbent window films can save energy because they can help reduce air conditioning loads in heavily cooling-dominated climates. Prices for reflective solar films range from $5.50 to $8.00 per square foot of installed film. Spectrally selective films offer reduced visible light blockage and have an installed cost of about $7.00 to $12.50 per square foot of glazing while Low-E films cost $6.00 to $9.50 per square foot. Advanced Low-E/high VT films cost from $11.00 to $18.00 per square foot. Costs are reduced for larger projects. No cost breakthroughs are anticipated and film costs have tended to increase with inflation.

Window films are not a “do-it-yourself” product. Installer training is definitely required and special procedures must be followed when installing window films. Warranties for the films are voided if installation is not performed by factory-trained and certified installers. All manufacturers offer a lifetime warranty for residential window film applications. Assuming a Low-E film total installed cost cost of $7.75/sf and a typical house 2,000 sf house with a window area equivalent to 15% of the floor area, yields a cost per treated house of $7.75 x 0.15 x 2000 = $2,325. Low-E film is designed to retain heat so should be placed on windows with all orientation. Low-E film with high visible light transmission carries a much higher installation cost.

Cost Effectiveness:

Simple payback, new construction (years): 33.8

Simple payback, retrofit (years): 33.8

What's this?

Cost Effectiveness is calculated using baseline energy use, best estimate of typical energy savings, and first cost. It does not account for factors such as impacts on O&M costs (which could be significant if product life is greatly extended) or savings of non-electric fuels such as natural gas. Actual overall cost effectiveness could be significantly different based on these other factors.

Comments:

Window films may be an appropriate retrofit for any commercial building type, including schools, hospitals, health care facilities, and offices. Only south- and west-facing windows need to be treated to eliminate “hot spots,” although, for aesthetic reasons, the entire building is often retrofitted with window film to provide a consistent appearance.

Energy savings benefits from using window films are greatly reduced when:

The existing commercial building already has double-pane or tinted windows;
Cooling loads are reduced by using an economizer or operable windows; and
The building is equipped with overhangs, vertical fins, awnings, or interior treatments like blinds or shades.

Paybacks – Commercial: In the commercial sector in the Pacific Northwest, simple paybacks from window film retrofit projects are not attractive, particularly when economizer cooling is employed. The simple paybacks in western Washington vary from about 37 to 94 years (for the no-economizer and with-economizer scenarios, respectively, and a conditioned south-facing exterior building zone). Paybacks in Boise range from 27 to 48 years. The simple paybacks in the scenario where an economizer is not used but electric resistance heating is used improve to only 31 and 23 years for Seattle and Boise, respectively. This analysis assumes heating and cooling are provided with a heat pump with an HSPF of 6.8 and SEER of 10.0 (representing equipment that does not comply with current code), an electrical energy rate of $0.08/kWh, and a Low-E window film total installed cost of $7.75 per square foot.

Paybacks – Residential: For residential retrofits, reflective and spectrally selective window films result in increased energy use in all heating-dominated Pacific Northwest locations (Seattle, Spokane, Boise, and Kalispell). Even the benefits of a Low-E window film retrofit on a single-pane, wood-framed window are compromised in residential applications because the film’s low SHGC reduces solar heat gain during the heating season, which results in increased electrical energy use for space heating. For residences equipped with electric heat pumps, simple paybacks for Low-E window film retrofits on single-pane, wood-framed windows exceed 95 years in western Washington and more than 30 years in Spokane, Boise, and Kalispell. Energy savings are negligible when Low-E window film is applied to clear, double-pane, residential windows.

Detailed Description:

Window films are an aftermarket or retrofit option, originally designed to solve problems with excessive heat gain or glare from an existing window; or to reduce furniture, drape, or product deterioration due to ultraviolet radiation exposure. The two primary reasons for justifying window film retrofits are improved comfort and reduced energy costs in cooling-dominated commercial or residential buildings.

Window film energy-saving benefits are greatly reduced when:

The existing building already has double-pane or tinted windows;
Cooling loads are reduced with use of an economizer or operable windows;
Cooling energy is reduced by using very efficient cooling equipment; and
The building is equipped with overhangs, vertical fins, awnings, or interior treatments like blinds or shades.

Major manufacturers include 3M, Solutia, Hanita, Huper Optik, Madico,Nexfil, Bekaert Specialty Films, Commonwealth Laminating and Coating,Johnson Laminating, and Southwall Technologies.

Standard Practice:

New construction must be in compliance with building codes. In this case, the immediate application of window films results in minimal energy savings. The Northwest Energy Efficiency Alliance (NEEA) 2011 residential building stock assessment of single-family homes indicates that 8.6% of the homes in the Pacific Northwest region have single-glazed, metal-frame windows and an additional 8.6% are equipped with wood- or vinyl-framed, single-pane windows. The majority of residences (73.7%) have double-pane glazing in wood, vinyl, or fiberglass frames.

Energy savings are relatively small and rarely cost-effective when window films are retrofitted onto double-pane windows. The target application for this retrofit technology is residences with existing single-pane windows and mechanical cooling. Many commercial buildings already employ sun control devices, including tinted windows, reflective shades or films, or are designed with overhangs or fins. Window film retrofits are often done to control glare or hot spots that develop in exterior south- or west-facing building walls.

Development Status:

Window films, readily available throughout the Pacific Northwest region, are rated by manufacturers and the National Fenestration Rating Council (NFRC). As of late 2012, the NFRC Certified Products Directory database contained information on 286 window film products. Most local film installers are authorized dealers for one or more manufacturers.

Window films are a mature technology with a wide range of performance values. Early versions of the films were designed for sun control and featured reflective or absorbent coatings. More recently, spectrally selective and Low-E films became available.

Non-Energy Benefits:

Window films are often sold to Pacific Northwest residential customers for reasons other than energy savings. They come in aesthetically pleasing tints and provide a number of secondary benefits, including UV light blockage, glare reduction, reduced hot spots, and increased shatter resistance. Most window films block 99% of the sun’s UV rays, which protects furniture, floors, décor, art work, and window merchandise displays. While they command a premium price, advanced Low-E, high visible transmittance (VT) window films avoid producing a gloomy interiorenvironment that could result in additional lighting use.

End User Drawbacks:

Some double-pane window manufacturers void their warranties when a homeowner places an “old technology” window film on their product.When an absorbent type of film gets hot, it heats the pane it is affixed to. The inner pane of glass then expands more than the cooler exterior pane, which can create stresses on the window and result in premature seal failure.Users must ensure that window warranties are not compromised prior to installing window films.

It is also important to note that window films with high visible reflectance (VR) will look more like a mirror than a window from the inside at night. During the day, the window resembles a mirror when viewed from the outside.Some homeowners' associations object to the installation of shiny or mirror-like coatings on windows in their jurisdiction.

Window films can produce glass cracking due to heat build-up if a dark absorbent film is used on non-strengthened glass that has a high solar exposure. Window films should not be retrofitted onto:

Single-pane windows larger than 100 square feet or double-pane windows larger than 40 square feet.
Clear glass thicker than 3/8-inch or tinted glass thicker than ¼-inch.
Glass with a nonstandard surface, such as reflective, laminated, wired, patterned, or textured glass.
Cracked or otherwise damaged glass.
Glass in concrete, solid aluminum, or solid steel framing.

Operations and Maintenance Costs:

Comments:

Window films require no maintenance, other than periodic cleaning with a non-abrasive cloth in order to maintain the appearance and clarity of the film.

Effective Life:

Comments:

Most manufacturers offer a lifetime warranty for residential window film applications. Some offer a warranty for as long as the homeowner remains in the house.

Competing Technologies:

A wide variety of other window treatments can be applied in residential and commercial settings, including:

Awnings to prevent direct sunlight from shining directly onto windows and reduce solar heat gain. When the sun’s heat is desired, retractable awnings are available. Awnings can reduce heat gain in the summer by up to 65% on south-facing windows and up to 77% on west-facing windows.
Exterior sun control devices, including exterior roller shades, roller shutters, and solar screens).
Exterior storm windows and shutters that allow for unrestricted views to the outside.
Interior insulated window panels, which are secured in place with magnetic strips or Velcro and can be removed when desired.
Interior window treatments, including drapes, curtains, blinds, covers, and insulating quilts. Window blinds are more effective at reducing summer heat gain than reducing winter heat loss. Slats can be adjusted to control light and ventilation. When closed, blinds can reduce heat gains by 45%. Draperies (medium colored with white plastic backing) can reduce heat gains by 33% and reduce heat losses in the heating season by 10%.
Window restoration because proper gasketing and sealing will improve airtightness.
Cellular insulated shades, which employ trackless or enhanced designs that run in tracks (see ET #474 in this database).
Advanced double- or triple-pane windows with argon gas fill and perhaps a Low-E coating.

Reference and Citations:

FSEC, 01/01/2007. About Window Films
Florida Solar Energy Center
Special Notes: Discusses the background of window films.

Gilbert McCoy, 06/01/2013. Residential and Commercial Sector Window Film Retrofits in the Pacific Northwest
WSU Energy Program

Steve DeBusk, 10/29/2010. A Review and Examination of EnerLogic™ Window Film Performance Claims
Global Energy Solutions

Alice Rosenberg, 05/01/2013. CEE Product Overviews: Energy Efficient Fenestration Options
Consortium for Energy Efficiency

Mudit Saxena, 12/21/2012. Advanced Window Film Technology Assessment – Phase 1 Report
Pacific Gas & Electric Company

E-Source, 01/01/2012. Window Film
Business Energy Advisor

ConSol, 02/07/2012. Energy Analysis for Window Films Applications in New and Existing Homes and Offices
International Window Film Association

Robert Bishop, 09/01/1992. New Retrofit Window Film Admits Light and Blocks Heat: Implications for Utility Rebates
E-Source Tech Memo

IPMVP, 08/13/2013. International Performance Measurement and Verification Protocol: Concepts and Options for Determining Energy and Water Savings, Volume 1
International Performance Measurement and Verification Protocol

Steve DeBusk, 01/13/2012. Measuring the Savings from Energy-Control Window Film Installation Using IPMVP Options C and D
Global Energy Solutions

Robin Mitchell, 05/18/2005. RESFEN5: for Calculating the Heating and Cooling Energy Use of Windows in Residential Buildings
Lawrence Berkeley National Laboratory

Robin Mitchell, 08/24/2011. COMFEN 4.1: Program Description: A PC Program for Calculating the Heating and Cooling Energy Use of Windows in Commercial Buildings
Lawrence Berkeley National Laboratory

Rank & Scores

Advanced Energy Efficient Window Films

There is no TAG available for this technology.

Market Potential

Advanced Energy Efficient Window Films

Last Edited:

11/21/2013 1:42:32 PM by AngelaP

Market Segment:

Window films may be an appropriate retrofit for any commercial building type, including schools, hospitals, health care facilities, offices, and commercial buildings. Only south- and west-facing windows need to be treated for “hot spot elimination,” although, for aesthetic reasons, the entire building is often retrofitted with window film to provide a consistent appearance. Energy savings benefits from use of window films are greatly reduced when:• The existing commercial building already has double-pane or tinted windows; • Cooling loads are reduced with an economizer or operable windows; and • The building is equipped with overhangs, vertical fins, awnings, or interior treatments like blinds or shades. These films are also aimed at the residential market.

Regional Fit:

Window films with low emissivity (Low-E) and high visible transmittance (VT) capability (known as Low-E/High VT) can help reduce winter heat loss in heating-dominated climates while allowing visible light to pass into the building. While their solar heat-blocking capability is slightly reduced, Low-E/High VT film replicates the performance of spectrally selective window films and represents the most desirable option in the cloudy western Washington and Oregon climate zones. While they come at a premium price, Low-E/High VT window films avoid producing a gloomy interior environment which could result in additional lighting use. High-end homeowners with attractive views often install window film to eliminate hot spots because they do not want to lose their view by closing blinds or drapes or installing reflective window films with low VT values. The Low-E/High VT films reduce eye-strain and glare, preserve views, and can save a small amount of energy.

Load Shape:

In cooling-dominated commercial buildings, window film retrofits can reduce peak electrical demands. In residential units where air conditioning systems or heat pumps provide mechanical cooling, window film retrofits produce cooling savings. But energy savings for space cooling produced by Low-E window films are offset by the need to run the space heating equipment for more hours during the heating season to offset the loss of solar heat gain. This can result in load shifting from the cooling to the heating season. Space heating could be provided by electrical resistance heating, heat pumps, or natural gas furnaces. Supplemental wood heat is often used for residential heating. The appropriate load shape is consistent with that obtained by replacing single-pane windows with advanced windows in single-family residential units or in manufactured housing. Additional load shapes of interest include those for schools, hospitals, and small retail shops. Applicable ProCost load shapes include:---Commercial - Existing Small Office and Retail Building Envelope Measure---Residential Central Air Conditioning - Cooling Zone 3---Residential Space Heating - Baseboard Heating Zone 3---Residential Space Heating - Forced Air Furnace Heating Zone 3---Residential Space Heating - Heat Pump Heating Zone 3

Performance Trajectory:

Not surprisingly, the market penetration for sun control window film is highest in the cooling-dominated South and southwest regions of the United States. Window films are a mature technology with a wide range of performance values. Early versions of the films were designed for sun control and featured reflective or absorbent coatings. More recently, spectrally selective and Low-E films became available. While they command a premium price, advanced Low-E/High VT window films avoid producing a gloomy interior environment, reducing the need for additional lighting use. These window films will likely continue to improve gradually over the years.

Cost Trajectory:

No cost breakthroughs are anticipated. Film costs have tended to increase with inflation over the years.

Product Supply and Installation Risk:

Window films are readily available throughout the Pacific Northwest region. They are manufactured by stable, well-established firms able to scale up as needed. It is unlikely that an increase in sales volume in this region would cause a product shortage. Window films are not a “do-it-yourself” product; most local film installers are authorized dealers for one or more manufacturers. Installer training is definitely required and special procedures must be followed when installing window films. Warranties for the films are voided if installation is not performed by factory-trained and certified installers. All manufacturers offer a lifetime warranty for residential window film applications.

Technical Dominance:

Window films are a retrofit technology; it does not make sense to use them on new construction that requires advanced windows. Existing residential units equipped with single-pane windows could upgrade to double-pane windows in a vinyl frame instead of undergoing a window film retrofit. Homes with double-pane windows could potentially upgrade to triple-pane windows. But, while energy savings can result, window upgrades come at a high cost. A recent study from the Pacific Northwest National Laboratory states, “…the cost effectiveness of the measure (from upgrading from a double-pane to a triple-pane window) as determined by the simple payback period, suggests that highly insulating window costs continue to make windows difficult to justify on a cost basis alone.” Window films and competing technologies such as replacement windows, storm windows, and other window treatments are mature technologies. On a cost-effectiveness basis, other technologies may or may not be competitive, but that competitive landscape is not expected to change appreciably in the foreseeable future.

Target Customer:

The primary customer for commercial properties is the building owner and the facilities manager, although the tenant would benefit directly from heating and cooling cost reductions, and may sometimes be a direct customer. Residential decision-makers include the homeowner and landlords. Window film retrofits may be considered for single-family residences, condominiums, and townhouses.

Market Channels:

Window films are manufactured by many companies with a wide variety of performance parameters. They are sold and installed by local distributors.

Regulatory Issues:

Neither commercial building owners nor homeowners have to acquire any permits to install window films. Installation is non-intrusive. Window films can be installed in one day and immediately begin to produce energy savings.

Other risks and barriers:

Some double-pane window manufacturers void their warranties when a homeowner places an “old technology” window film on their product. When an absorbent-type of film gets hot, it heats the pane it is affixed to. The inner pane of glass then expands more than the cooler exterior pane, which can create stresses on the window and result in premature seal failure. Before installing window films, ensure that window warranties are not compromised. Note that window films with high visible reflectance (VR) will look more like a mirror than a window from the inside at night. During the day, the window resembles a mirror when viewed from the outside. Some homeowners associations object to the installation of shiny or mirror-like window coatings on homes in their jurisdiction.Window films can produce glass cracking due to heat build-up if a dark absorbent film is used on non-strengthened glass that has a high solar exposure. Window films should not be retrofitted onto:• Single window panes larger than 100 square feet or double-pane windows larger than 40 square feet.• Clear glass thicker than 3/8th-inch or tinted glass thicker than ¼-inch.• Glass with a nonstandard surface, such as reflective, laminated, wired, patterned, or textured glass.• Cracked or otherwise damaged glass.• Glass in concrete, solid aluminum, or solid steel framing.Residential films are not sold on the basis of energy savings claims; instead, they are purchased to improve comfort, eliminate hot spots, preserve view, and add UV protection. The biggest barrier to the adoption of window films as an energy savings measure is their high total installed costs and extended simple paybacks.

Basis of Savings:

Energy savings benefits due to window film retrofits are expected to vary widely based on the baseline window type (single pane, double pane); performance of the film employed; local climate; building orientation; window-to-wall ratio (in each direction); the presence of shading produced by vegetation, other buildings, overhangs, fins, or awnings; building heating and cooling temperature setpoints and setbacks; use of economizers or operable windows; and the type and performance of HVAC system in use. A site-specific custom protocol would have to be developed.

Citations:

Florida Solar Energy Center, “About Window Films”: http://www.fsec.ucf.edu/en/consumer/buildings/homes/windows/films.htm.Steve DeBusk, Global Energy Solutions Manager, Solutia, Inc., “A Review and Examination of EnerLogic™ Window Film Performance Claims”: http://www.enerlogicfilm.com/pdf/EnerLogic-White-Paper.pdf. Alice Rosenberg, Residential Windows Working Group, “CEE Product Overviews: Energy Efficient Fenestration Options,” Consortium for Energy Efficiency, May, 2013. Mudit Saxena, Heschong Mahone Group, Inc., “Advanced Window Film Technology Assessment-Phase 1 Report,” prepared for Pacific Gas & Electric Company, December 21, 2012: http://www.etcc-ca.com/sites/default/files/reports/ET11PGE1041%20-%20PGE%20Adv.%20Films%20ET%20Phase%201%20Tech%20Assessment%20Report_1.pdf. E-Source, “Window Film,” Business Energy Advisor, January 1, 2012. ConSol Energy and Environmental Solutions, “Energy Analysis for Window Films Applications in New and Existing Homes and Offices,” prepared for the International Window Film Association, February 7, 2012: http://www.iwfa.com/Portals/0/PDFDocs/IWFA%20Energy%20Study%20FINAL.pdf. Robert C. Bishop and Michael Shepard, E-Source Tech Memo, “New Retrofit Window Film Admits Light and Blocks Heat: Implications for Utility Rebates,” TM-92-2, September 1992. Arizona Public Service Company, “Windows and Window Treatments,” Energy Answers for Business.Efficiency Valuation Organization, “International Performance Measurement and Verification Protocol: Concepts and Options for Determining Energy and Water Savings, Volume 1,” EVO 10000-1:2012, January 2012: http://www.evo-world.org/index.php?option=com_docman&task=doc_view&gid=1543. Steve DeBusk, Global Energy Solutions Manager, Solutia, Inc., “Measuring the Savings from Energy-Control Window Film Installation Using IPMVP Options C and D”: http://www.bomaconvention.org/boma2012/CUSTOM/Case%20Study%20Solutia.pdf.Ben Larson, Ecotope, “SEEM Workshop,” October 31, 2011. Robin Mitchell, et al., Windows and Daylighting Group, Building Technologies Program, Lawrence Berkeley National Laboratory, “RESFEN5: for Calculating the Heating and Cooling Energy Use of Windows in Residential Buildings,” LBNL-40682, May 2005: http://windows.lbl.gov/software/resfen/50/RESFEN50UserManual.pdf .Robin Mitchell, et al., Windows and Daylighting Group, Building Technologies Program, Lawrence Berkeley National Laboratory, “COMFEN 4.1: Program Description: A PC Program for Calculating the Heating and Cooling Energy Use of Windows in Commercial Buildings,” October, 2012: http://windows.lbl.gov/software/comfen/4/COMFEN4.0-UserManual.pdf.

Completed:

11/21/2013 1:42:32 PM by Angela Phillips