LOW-E RETROFIT ADD-ON FILMS - CONTENT: Compare Energy Efficiency of Low-E Glass vs Quad Glazing: Add-on films for low-e energy-efficient window glazing, Low-e window films for upgrading existing windows, Winter films and all-weather films retain indoor heat in cold weather, Low-e coated films for inside storm windows,
Questions & answers about using add-on or retrofit films to improve window energy efficiency. Solar Age Magazine Articles on Renewable Energy, Energy Savings, Construction Practices
Comparing Energy Efficiency of Low-E Glass vs Quad Glazing
The text below is reprinted/adapted/excerpted with permission from Solar Age Magazine - editor Steven Bliss.
Low-e Window Retrofit Film Products
Question: are there any low-e coated products for window retrofits?
Are there any low-e coated products available for retrofitting existing windows? - Ed Swiderski, Pawtuckett RI
Answer: Yes several low-e window films and an inside storm window
Two low-e window films and one inside storm window were available in the mid 1980's and more such products are currently provided by several manufacturers.
The add-on or "retrofit" low-e window films are applied to the inside of the window glass with a squeegee, using water as the adhesive. These "winter films" or "all-weather" films are tuned to retain winter heat and reject some outside heat gain.
They probably make the most sense as window energy improving retrofits in houses located north of the Mason-Dixon line.
Scotch-tint Plus All Season claims to reduce heat gain by 60 percent and wintertime heat loss through the window by 40 percent. it also blocks 98 percent of UV light that fades indoor furnishings. Scotch-tint is available from 3-M Co., St. Paul MN.
The second low-e retrofit window film is Gila River Products' [Chandler AZ] PWD-5 with roughly similar characteristics to the 3-M Scotch-tint film.
With a winter U-value of .85, this film ups the R-value of a single pane 1/8-inch thick window [glass] from around .90 to 1.18, a 31 percent improvement in window efficiency.
What is lost when a low-e film like these is applied to a window is some useful solar gain and light in winter, due to the film's low transmittance (0.55).
To our knowledge, the only low-e retrofit storm window is the Windo-Tite unit. It is an aluminum-framed single window that attaches to the inside of the primary window via swivel clips or sash locks. It has a tested U-value of .408 (r-2.45 for storm plus primary window). Amesbury Industries, [Amesbury MA] supplies the glazing frames and accessories to local distributors who make up the window units.
For more up to date information about the performance of films to increase solar collector efficiency, see SOLAR COLLECTOR FILMS
The question-and-answer article above paraphrases, quotes-from, updates, and comments an original article from Solar Age Magazine and written by Steven Bliss.
This article is reprinted/adapted/excerpted with permission from Solar Age Magazine - editor Steven Bliss.
Readers should also see SUNGAIN, FILMS, LOW-E GLASS for details about use of Sungain film on windows and window film selection and installation.
A wide range of energy conservation and solar energy topics is found at SOLAR ENERGY SYSTEMS. Contact us to suggest text changes and additions and, if you wish, to receive online listing and credit for that contribution.
Definition of Window Coating or Film Emissivity & Typical Emissivity Numbers for Low-E Films & Coatings
Window glazing may be factory-coated or as this article describes, an add-on adhesive low-e (low emissivity) film may be adhered to the inside or outside window surface (or both).
The emissivity of a window is a measure of its insulating performance expressed as the percentage of near-to-the-window infra-red heat in a room that is reflected back into the room (reducing heat loss from the building to outdoors), or from outside, the percentage of near infra-red-heat that is reflected back away from the window surface (reducing heat gain through the window and into the building).
A window film emissivity of 0.07 means that 0.93 or 93% of the room's nearby infra-red heat is reflected back into the building interior - signifiantly reducing winter heating costs, depending on what other building heat loss prevention measures have been taken. See our Watch Out note below.
A window film emissivity of 0.33 means that 0.67 or 67% of the room's nearby infra-red heat is reflected back into the building interior
A window film emissivity of 0.70 means that 0.30 or 30% of the room's nearby infra-red heat is reflected back into the building interior.
A window film emissivity of 0.81 means that 0.19 or 19% of the room's nearby infra-red heat is reflected back into the building interior.
In short, lower emissivity numbers mean more IR heat reflection (less heat is emitted through the window glazing) back into the occupied space. There are currently two low-e film performance ranges, depending on what product you buy.
Conventional low-e window film has a typical emissivity rating of 0.33, reflecting 0.67 or 67% of the near infra-red heat in a room back into the room interior. This film will improve the energy efficiency of a conventionally-glazed window by about 44% with the warnign that some low-e window films may produce a distracting irridescent or shiny surface dependign on the type of interior lighting used. Compact fluorescent bulbs tend to produce this irridescent sheen.
High performance low-e window film has extremely-low emissivity ratings, down as low as 0.07, reflecting 0.93 or 93% of the nearby infra-red heat back into the building interior. Expert sources we reviewed claimed a window insulating performance improvement of "up to" 92%.
Watch out: the energy savings potential of adding low-emissivity window films or buying low-e replacement windows or installing low-e windows in new construction will be limited if other building heat loss (or in hot climates un-wanted heat-gain) measures are not taken. For example, if there are signficant air leaks in the building or if the building wall and ceiling or roof insulation blankets are incomplete, the energy costs of those defects are likely to overwhelm any potential benefit of low-emissivity films or coatings on windows.
See ENERGY SAVINGS PRIORITIES
Sources of Low-E Add-On or Stick-On Window Films & Window Film Detection Instruments
3M Outdoor Window Insulator Kit, Two Pack, 2170 W-6, Product ID: 3M 2170 W-6 UPC: 00-051141-32384-8, 00051141323848 Stock ID: 70-0050-7990-3, 70005079903, available from re-sellers, this is a current version of Scotch Tint window films discussed by Steve Bliss in the article above. To review the differences among six different 3M™ window film products see the window film manual below.
Scotchtint™ / Scotchshield™ Window Film Manual [PDF], 3M™ Corporation, 2003. Abstract quoted from this window film selection & installation guide: Patented window films that improve comfort and cut energy costs by reducing
heat loss and solar heat gain through windows. The films can improve
aesthetics by providing uniformity to the exterior appearance of windows, while
not impairing the view. Other benefits include reduction of UV damage to interior
materials, reduced temperature imbalances between sunny and shady ares of
the building, improve glass safety and increased daytime privacy.
3M Consumer Safety and Light Management Department 1-800-480-1704
Building suppliers such as Lowes and Home Depot are retailers of several low-E window films
EDTM Double Pane Low E Coating Detector,
Part Number: AE1601, about $300. U.S.D., product description excerpt: Confirm the invisible Low E coating is properly installed into your double pane IG units with a single test from a single side. You can also test a triple pane window by testing both sides of the window. For full triple pane Low-E detection, see the Glass-Chek PRO.
EnerLogic® low-e window film, Website: http://www.enerlogicfilm.com/products, Excerpt from product description: EnerLogic® low-e window film reduces solar heat gain and radiant heat loss, creating year-round heating and cooling savings of up to three times as much as conventional window film with comparable light transmission. - See more at: http://www.enerlogicfilm.com/products#sthash.okXs1CCh.dpuf
In Australia contact EnerLogic at: 275 Canterbury Road,
Canterbury VIC 3126
Free Call: 1800 134 776
In New Zealand contact EnerLogic at: 24A Tarndale Grove,Albany,
Free Call: 0800 134 776
Gila 36-in W x 180-in L Platinum Heat-Control Adhesive Window Film
Item #: 23153 | Model #: LES361, widely sold online and at building suppliers
Hanita Pacific Pty Ltd
Unit 4, 50 Rooks Rd
Nunawading VIC 3131
Tel: 1300 456 700
Fax: 1300 456 600
firstname.lastname@example.org Website: http://www.hanitacoatings.com/ selling low-e films in Australia & New Zealand
Solar Guard Saint Gobain, [Dream on if you hope to find actual contact information such as a mailing address for this company - Ed.] "Solar Gard window film products. For more information, please contact Customer Service at
1800 251 575 or fill out the form [at http://www.solargard.com/] " markets low-e films in Australia and other countries.
SolarShield, U.K. low-e window coatings and films, Solarshield Limited
20/20 Business Park
St Leonards Road
0845 130 6232
Local Rate Phone No:
0162 275 4660
Madico window films, coatings, laminates, Madico Window Films
2630 Fairfield Ave. South
St. Petersburg, FL
33712, Website: http://www.madico.com/, Excerpt from the company's description: Madico is a world leader in the COATING, LAMINATING, and CONVERTING of films in wide width, roll-to-roll format. Our products are multilayered, engineered films primarily targeting applications in Energy-related markets such as Solar Control Window Films, Photovoltaic Backsheets, and Safety/Security Films.
Q&A: Low-e Retrofit Products - Window Films - PDF version; use your browser's back button to return to this page. Original article, Solar Age Magazine, September 1986, adapted and updated for InspectAPedia.com in 2011.
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Solar Age Magazine was the official publication of the American Solar Energy Society. The contemporary solar energy magazine associated with the Society is Solar Today. "Established in 1954, the nonprofit American Solar Energy Society (ASES) is the nation's leading association of solar professionals & advocates. Our mission is to inspire an era of energy innovation and speed the transition to a sustainable energy economy. We advance education, research and policy. Leading for more than 50 years.
ASES leads national efforts to increase the use of solar energy, energy efficiency and other sustainable technologies in the U.S. We publish the award-winning SOLAR TODAY magazine, organize and present the ASES National Solar Conference and lead the ASES National Solar Tour – the largest grassroots solar event in the world."
Steve Bliss's Building Advisor at buildingadvisor.com helps homeowners & contractors plan & complete successful building & remodeling projects: buying land, site work, building design, cost estimating, materials & components, & project management through complete construction. Email: email@example.com
Steven Bliss served as editorial director and co-publisher of The Journal of Light Construction for 16 years and previously as building technology editor for Progressive Builder and Solar Age magazines. He worked in the building trades as a carpenter and design/build contractor for more than ten years and holds a masters degree from the Harvard Graduate School of Education.
Excerpts from his recent book, Best Practices Guide to Residential Construction, Wiley (November 18, 2005) ISBN-10: 0471648361, ISBN-13: 978-0471648369, appear throughout this website, with permission and courtesy of Wiley & Sons. Best Practices Guide is available from the publisher, J. Wiley & Sons, and also at Amazon.com
3M Corporation, 3M Energy Control Products Project, Building 224-5S, St. Paul MN 55144 [1980's]
Mark Cramer Inspection Services Mark Cramer, Tampa Florida, Mr. Cramer is a past president of ASHI, the American Society of Home Inspectors and is a Florida home inspector and home inspection educator. Mr. Cramer serves on the ASHI Home Inspection Standards. Contact Mark Cramer at: 727-595-4211 mark@BestTampaInspector.com
John Cranor is an ASHI member and a home inspector (The House Whisperer) is located in Glen Allen, VA 23060. He is also a contributor to InspectApedia.com in several technical areas such as plumbing and appliances (dryer vents). Contact Mr. Cranor at 804-747-7747 or by Email: firstname.lastname@example.org
Passive Solar Design Handbook Volume I, the Passive Solar Handbook Introduction to Passive Solar Concepts, in a version used by the U.S. Air Force - online version available at this link and from the USAF also at wbdg.org/ccb/AF/AFH/pshbk_v1.pdf
Passive Solar Design Handbook Volume II, the Passive Solar Handbook Comprehensive Planning Guide, in a version used by the U.S. Air Force - online version available at this link and from the USAF also at wbdg.org/ccb/AF/AFH/pshbk_v2.pdf [This is a large PDF file that can take a while to load]
Passive Solar Handbook Volume III, the Passive Solar Handbook Programming Guide, in a version used by the U.S. Air Force - online version available at this link and from the USAF also at wbdg.org/ccb/AF/AFH/pshbk_v3.pdf
"Passive Solar Home Design", U.S. Department of Energy, describes using a home's windows, walls, and floors to collect and store solar energy for winter heating and also rejecting solar heat in warm weather.
"Solar Water Heaters", U.S. Department of Energy article on solar domestic water heaters to generate domestic hot water in buildings, explains how solar water heaters work. Solar heat for swimming pools is also discussed.
"Heat-Transfer Fluids for Solar Water Heating Systems", U.S. DOE, describes the types of fluids selected to transfer heat between the solar collector and the hot water in storage tanks in a building. These include air, water, water with glycol antifreeze mixtures (needed when using solar hot water systems in freezing climates), hydrocarbon oils, and refrigerants or silicones for heat transfer.
"Solar Water Heating System Freeze Protection", U.S. DOE,using antifreeze mixture in solar water heaters (or other freeze-resistant heat transfer fluids), as well as piping to permit draining the solar collector and piping system.
"Solar Air Heating" U.S. DOE also referred to as "Ventilation Preheating" in which solar systems use air for absorbing and transferring solar energy or heat to a building
"Solar Liquid Heating" U.S. DOE, systems using liquid (typically water) in flat plate solar collectors to collect solar energy in the form of heat for transfer into a building for space heating or hot water heating. The term "solar liquid" is used for accuracy, rather than "solar water" because the water may contain an antifreeze or other chemicals.
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. Tel: (416) 964-9415 1-800-268-7070 Email: email@example.com. The firm provides professional home inspection services & home inspection education & publications. Alan Carson is a past president of ASHI, the American Society of Home Inspectors. Thanks to Alan Carson and Bob Dunlop, for permission for InspectAPedia to use text excerpts from The Home Reference Book & illustrations from The Illustrated Home. Carson Dunlop Associates' provides extensive home inspection education and report writing material.
The Illustrated Home illustrates construction details and building components, a reference for owners & inspectors. Special Offer: For a 5% discount on any number of copies of the Illustrated Home purchased as a single order Enter INSPECTAILL in the order payment page "Promo/Redemption" space.
TECHNICAL REFERENCE GUIDE to manufacturer's model and serial number information for heating and cooling equipment, useful for determining the age of heating boilers, furnaces, water heaters is provided by Carson Dunlop, Associates, Toronto - Carson Dunlop Weldon & Associates Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on any number of copies of the Technical Reference Guide purchased as a single order. Just enter INSPECTATRG in the order payment page "Promo/Redemption" space.
The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume.
Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on these courses: Enter INSPECTAHITP in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
The Horizon Software System manages business operations,scheduling, & inspection report writing using Carson Dunlop's knowledge base & color images. The Horizon system runs on always-available cloud-based software for office computers, laptops, tablets, iPad, Android, & other smartphones