SUNGAIN, FILMS, LOW-E GLASS - CONTENTS: Sources of high-transmission Sungain film made by 3M. Films to increase solar collector efficiency. Table of window glazing properties: energy transmission, heat reflection, efficiency. Definitions of glazing film types, low-e glass, energy properties of each. Window Glazing Energy Products: What are the Differences in Function & Use Among Low-Transmission Films, Low-E glass, Coated Reflective Films & High Transmission, Low Emissivity Films or Reduced-Iron-Content Glass? Solar Age Magazine Articles on Renewable Energy, Energy Savings, Construction Practices
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Window films, Sungain:
This article discusses sources for window films and coating to control heat gain, heat loss, heat transmission - high-transmission 3M Sungain film.
We list and discuss window glazing energy products and answer: what are the differences in function & use among low-transmission films, low-E glass, coated reflective films & high transmission, low emissivity films or reduced-iron-content glass?
Sungain Film Sources for High-Transmission Film Windows
Accompanying text is reprinted/adapted/excerpted with permission from Solar Age Magazine - editor Steven Bliss.
For more up to date information about the performance of films to increase solar collector efficiency, see SOLAR COLLECTOR FILMS. Contact us to suggest text changes and additions and, if you wish, to receive online listing and credit for that contribution.
The question-and-answer article below paraphrases, quotes-from, updates, and comments an original article from Solar Age Magazine and written by Steven Bliss.
I've had little luck [back in 1984] locating quad glazing with Sungain™ film (Solar Age, 2/83, 9/83) locally. Do you have any information on where I can buy quad-glazed glass window units? -- Rick Essman, Carson City NV
High-transmission Sungain film is made by the 3M Company. According to M.J. Johnson of 3M's Energy Control Products, quad-pane and tri-pane units and windows with Sungain film were [by the mid 1980's in the U.S.] available from several manufacturers, and 3M continued to add more of them across North America by 1985.
Sungain is a thin plastic film, discussed in Popular Science Magazine in 1982 and produced by 3M Corporation. Sungain plastic film admits more heat than glass through the same area.
Quad-glazed units (glass only):
Air Seal Insulating Glass Units Co., 522 Powell St., Gloucester City NJ 80830 609-456-3922
Weather Shield Mfg., Inc., 531 North 8th St., Medford WI 54451 715-748-2100
Check with the glazing and window manufacturers for prices and availability.
Window Glazing Energy Products: What are the Differences in Function & Use Among Low-Transmission Films, Low-E glass, Coated Reflective Films & High Transmission, Low Emissivity Films or Reduced-Iron-Content Glass?
Definition & Uses of of Low Transmission Window Films and Low-E Glass
Low-transmission films such as Scotchtint™ were developed to block solar transmission through window glass into the building interior, avoiding un-wanted heat gain in some buildings. Low-transmission, heat reflecting films would not help solar collector efficiency.
Low-E glass, low-emissivity glass, low infrared reflectance glass (these all mean the same thing) produced by Airco Temescal, Berkeley CA, and Guardian Industries, Carelton Michigan, uses a transparent coating that reflects heat. Infrared energy is long-wave energy (longer than visible light), and is in essence, radiant heat. If we reflect radiant heat from a window surface we are reducing the heat that passes through the window.
Practically speaking, in winter indoor heat may be reflected back into the interior, reducing heat loss through low-e glazed windows by radiation loss by 1/3 to 1/2. Of course air bypass leaks in a building can easily overcome the energy savings from special window glazing. See AIR LEAK MINIMIZATION and AIR SEAL STRATEGIES.
In summer, heat from bright sunlight may be reflected back outdoors, reducing the heat transmitted to the building interior. Thus low-e glass or Heat Mirror film coated glass may reduce heating costs in the heating season and cooling costs (by letting in less solar heat) during the cooling season.
Low-e glass, compared with un-treated glass, has a slight bluish color.
Coated plastic reflective films, such as Heat Mirror, produced by Southwall Corp., Palo Alto, CA, also reflect heat as does the low-e glass mentioned above.
Low transmission glazing films such as Heat Mirror (a 2-mil polyester reflective film) and Low-E glass have been installed on airplane windshields to increase pilot protection, comfort, and visibility since World War II. -- op cit. A special advantage on airplanes was the fact that the glass is electrically conductive: sending an electrical current through the glass could be used to remove fogging, frost, or ice.
The Southwall Corporation was formed by the original developers of coated plastic reflective films for these applications, including John Brooks, Sean Wellesley-miller, and physicist Day Chahroudi who had observed low-E and coated windshield technology, working at MIT, adapted the process to produce a transparent insulation leading to a whole industry of special glazing intended for use in solar and energy conservation applications.
Heat mirror film coated glass, compared with un-treated glass, looks about the same.
2. U-value is the measurement of heat transmission through a material - it's the reciprocal of R-value. R-value is a material's resistance to heat transfer.
Definition & Uses of High Transmission, Low Emissivity Films
The high-transmission, low-emissivity films such as Heat Mirror™ or 3-M's Sungain™ might boost solar collector efficiencies in some applications, particularly high-temperature collectors in cold climates. In this case, the added insulation value of the film might offset the transmission losses.
The actual efficiency gains for the solar collector may still not justify the added expense.
As these products were developed for building glazings (windows), their durability in solar collector applications is in question.
The effects of high temperatures, thermal cycling, and high UV exposure on the window glazing film had (in the 1980's) only been studied in a preliminary way. 3M informed us that its Sungain film will become brittle at temperatures above 250 degF., prohibiting its use in some solar collector applications.
Reduced-iron-content glass, such as Solakleer, produced by General Glass, International, New Rochelle, NY, also admits more heat than ordinary glass.
Percentage of Solar Energy Transmitted Through High-Transmission Glazings
Percent of solar energy transmitted through the glazing
93 - 96%
Ordinary window glass
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 about Sungain film by 3M and used on glazing or windows, quotes-from, updates, and comments an original article from Solar Age Magazine and written by Steven Bliss.
The link to the original Q&A article in PDF form immediately below is preceded by an expanded/updated online version of this article.
Q&A on Sungain Sources - where to find quad glazing with Sungain™ film - PDF version, use your browser's back button to return to this page
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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: firstname.lastname@example.org
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: email@example.com
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
"Wonder Windows, Two Let In More Sun, Two Keep In More Heat", V. Elaine Smay, Popular Science, April 1982
Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. Tel: (416) 964-9415 1-800-268-7070 Email: firstname.lastname@example.org. 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.
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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.
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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