Solar Gains / Losses: Conventional Glass vs. Heat Mirror Glazing
InspectAPedia^® -

Usage guide for Heat Mirror window glazing
Why we reduce the total window aperture space when using Heat Mirror glazing compared with double-glazed glass
Solar gains and losses compared between clear glass windows and Heat Mirror glazing
Solar Age Magazine Articles on Renewable Energy, Energy Savings, Construction Practices

This article describes low-e window films that can be added to existing windows to improve window efficiency and improve solar gain in cold weather.

InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers nor with topics or services discussed at this website.

© Copyright 2012 InspectAPedia.com, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use page top links to major topics or use links at the left of each page to navigate within topics and documents at this website. Green links show where you are in a document series or at this website.

Comparing Energy Efficiency of Low-E Glass vs Quad Glazing

Readers should also see SUNGAIN, FILMS, LOW-E GLASS for details about use of Sungain film on windows and window film selection and installation, and see WINDOWS & DOORS our home page for window and door information. 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.

The question-and-answer article below paraphrases, quotes-from, updates, and comments an original article from Solar Age Magazine and written by Steven Bliss.

Low-e Window Retrofit Film Products

Question:

I am designing a passive solar home and I am considering using Heat Mirror instead of clear double glass. Am I correct in assuming that I can increase the glazing area in relationship to the mass to compensate for Heat Mirror's lower solar transmittance? - Bob Hutchinson, Kingsville Ontario

Answer: Surprise: not according to an expert! Decrease the glazing aperture when using Heat Mirror glazing.

Not according to Timothy Johnson, passive solar specialist at MIT.

He advises just the opposite: reduce the glazing aperture.

The reasoning goes something like this: the transmittance of clear double-paned glass is around 0.89, and the transmittance of Heat Mirror 88 glazing is 0.69 - 22 percent less.

So you get less solar gain with Heat Mirror glazing than with clear double glass.

But the insulating value of Heat Mirror 88 (1 1/4-inch thickness) is R-3.84, 52 percent better than the R-2 of double-glazed glass windows.

In going from clear double-paned glass window glazing to Heat Mirror 88 window glazing, the increased insulation value outweighs the decreased solar energy transmittance.

You get less heat transmitted from the sun to indoors, but you lose still less heat from inside the building to outdoors.

To prevent overheating you will need to reduce the window aperture to about 75 percent of that you would have used for double-paned glass, suggests Johnson.

For more up to date information about the performance of films to increase solar collector efficiency, see SOLAR COLLECTOR FILMS

As we discuss in more detail at SUNGAIN, FILMS, LOW-E GLASS, here is a quick comparison of window types and their efficiencies:

This article is reprinted/adapted/excerpted with permission from Solar Age Magazine - editor Steven Bliss.

Original article source:

Q&A: Solar Gains & Losses: Conventional Glass vs Heat Mirror Glazing - 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.

Questions & Answers regarding this article

Ask a Question or Search InspectAPedia

HTML Comment Box is loading comments...

Recommend / Share this Article

...

Technical Reviewers & References

InspectAPedia.com^® - Daniel Friedman - Publisher & Editor.
InspectAPedia Bookstore lists recommended books, organized by topic & available for purchase. Most of our articles also include a list of recommended books for the specific article topic as well as other references, and information sources.
Critique, contributions wanted: Contact Us to suggest corrections or additions to articles at this website, and if you wish, to receive online listing and credit as a contributor. Particular thanks are due to the many experts and also consumers who read and critique technical articles at InspectAPedia.com.
Additional technical contributors & reference sources for this article are listed below.

Use links just below or at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

INSULATION INSPECTION & IMPROVEMENT
WINDOWS & DOORS
  ALUMINUM WINDOWS
  Best Practices Guide for Windows & Doors:
  CLIMATE, WINDOW CHOICES FOR
  CONDENSATION on WINDOWS & SKYLIGHTS
  Doors, Exterior, Energy Efficiency Guide
  Doors, Exterior Flashing Details
  Doors, Exterior, Frames
  DOORS, EXTERIOR, Selecting & Installing
  DOORS, INTERIOR
  FIBERGLASS WINDOWS
  GLASS vs HEAT MIRROR SOLAR GAIN/Loss
  HURRICANE, WIND, & STORM-Resistant WINDOWS
  LOW-E WINDOW GLAZING
  LOW-E VS QUAD-GLAZING
  LOW-E RETROFIT ADD-ON FILMS
  POLYCARBONATE GLAZING
  SITE BUILT DOUBLE GLAZED WINDOWS
  SKYLIGHTS, Guide to Choosing & Installing
  Skylight Condensation Problems
  Skylight Design Issues
  Skylight Energy Efficiency
  Skylight Installation Procedures
  SKYLIGHT LEAK DIAGNOSIS & REPAIR
  SKYLIGHT VENTILATION DETAILS
  SLIDING GLIDING WINDOW DEFECTS
  SLOPED GLAZING DETAILS
  SOLAR SHADES & SUNSCREENS
  STORM WINDOW INTERIOR
  STORM WINDOW PLASTIC CHOICES
  STORM WINDOW WEEP HOLES
  SUNGAIN, FILMS, LOW-E GLASS
  SUNSPACE GLAZING for SUNTANNING
  VERTICAL GLAZING DETAILS
  VINYL WINDOWS
  VINYL / PVC WINDOW WARPING
  WINDOW / DOOR ENERGY EFFICIENT, DOE
  WINDOW / DOOR AIR LEAK SEALING HOW TO
  Window Certification
  WINDOW EFFICIENCY Features & Ratings
  WINDOW FLASHING & SEALING Guide
  WINDOW GLAZING Based on Climate
  WINDOW HARDWARE PHOTOS
  Window Installation, Flange-Type
  Window Installation, w/ Integral Brickmold
  WINDOW LEAKS INTO BASEMENT
  Window Materials & Construction
  Window Types, Guide
  WINDOW TYPES - Photo Guide
  Window & Door Sources

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."
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.
Excerpts with updates and annotations expanding the original Best Practices Guide text can be found in the online review and book summary at BEST CONSTRUCTION PRACTICES GUIDE and also at DECK & PORCH CONSTRUCTION, at INDOOR AIR QUALITY IMPROVEMENT GUIDE, and in other articles found at InspectAPedia.com such as HOUSEWRAP AIR & VAPOR BARRIERS, SOUND CONTROL in buildings, and other topics.
3M Corporation, 3M Energy Control Products Project, Building 224-5S, St. Paul MN 55144 [1980's]
Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. (416) 964-9415 1-800-268-7070 info@carsondunlop.com. Thanks to Alan Carson and Bob Dunlop, for permission to use illustrations from their publication, The Illustrated Home which illustrates construction details and building components. Carson Dunlop provides home inspection education including the ASHI-adopted Home Inspection Training Program (home study course), publications such as the Home Reference Book, report writing materials including the Horizon report writer, and home inspection services. Alan Carson is a past president of ASHI, the American Society of Home Inspectors.
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
The Passive Solar Design and Construction Handbook, Steven Winter Associates (Author), Michael J. Crosbie (Editor), Wiley & Sons, ISBN 978-047118382 or 0471183083 is available at Amazon.com and via the The Passive Solar Design and Construction Handbook, Steven Winter Associates (Author), Michael J. Crosbie (Editor), Wiley & Sons, ISBN 978-047118382 or 0471183083 is available at Amazon.com and via the InspectAPedia Bookstore
"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 Exchangers for Solar Water Heating Systems", U.S. DOE describes the types of solar water heater heat exchange methods between the sun and the building's hot water supply
"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 Maintenance and Repair", U.S. DOE
"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.
"Scaling and Corrosion in Solar Water Heating Systems", U.S. DOE
www.energysavers.gov/your_home/water_heating/index.cfm/mytopic=12850 is the base U.S. DOE website for these articles
"Active Solar Heating Systems", U.S. Department of Energy, including
"Radiant Heating Systems" U.S. DOE
"Absorption Heat Pumps & Coolers", U.S. DOE
"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

Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
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.
...

Free Encyclopedia of Building & Environmental Inspection, Testing, Diagnosis, Repair

Ask a Question or Search InspectAPedia

Comparing Energy Efficiency of Low-E Glass vs Quad Glazing

Low-e Window Retrofit Film Products

Question:

Answer: Surprise: not according to an expert! Decrease the glazing aperture when using Heat Mirror glazing.

Original article source:

Questions & Answers regarding this article

Ask a Question or Search InspectAPedia

Technical Reviewers & References

Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair