This book includes a plain text version that is designed for high accessibility. To use this version please follow this link.
COMFORT KNOW THE SCIENCE
For homeowners, how comfortable a house feels can be just as important as its energy efficiency. An older win- dow with a lower glass temperature feels colder be- cause more heat is radiated from a person’s body to the window.


Cold glass can also create uncomfortable drafts as air next to the window is cooled and drops to the floor. This sets up an air movement pattern that feels drafty and accelerates heat loss.


High-performance windows with lower u-factors will result in a higher interior window temperature in winter and thus greater comfort. Proper installation along with weatherstripping designed to seal tightly will also improve comfort by reducing cold air leakage.


During the summer, direct sunlight strikes people and surfaces, creating overheating and discomfort. Windows with low solar heat gain coefficients will re- duce the solar radiation coming through the glass. Low solar heat gain low-e glass reduces heat gain while still providing sufficient light and view.


LESS FADING AND CONDENSATION BLOCK THE RAYS
High-performance windows with new glazing technologies make homes more comfortable. They create warmer interior glass surfaces, reducing frost and condensation. High-performance windows with warm edge technology and insulating frames have such a warm interior surface that condensation on interior surfaces is significantly reduced under all conditions.


Another concern for homeowners is the effect of sunlight on the home and its contents. Many organic materials, such as carpet, fabrics, paper, artwork, paints, and wood may fade upon exposure to sunlight. Window selection can influence the type and intensity of transmitted radiation.


Ultraviolet (UV) rays are the most harmful radiation in sunlight. They are the most energetic and thus most likely to break chemical bonds, leading to fading and degradation.


Coatings on glass can reduce the UV transmitted by up to 75%. UV absorbers can be incorporated into thin plastic films in multilayer windows or as an interlayer in laminated glass. In both cases, the UV transmission can be reduced to less than 1%. However, it is important to note that the remaining visible light that is transmitted can still cause fading in some materials. Using low-e coated glass or windows incorporating plastic layers rather than clear uncoated glass will reduce fading.


 


GLOSSARY OF TERMS
KNOW THE LINGO


> Air Infiltration
The amount of air that passes between a window sash and frame, measured in cubic feet per minute per square foot of frame area.


> Argon Gas
A colorless, odorless, inert gas that fills the otherwise empty space within an insulating glass unit.


> Efficient Windows Collaborative
Organization that provides detailed reports and studies on the value of using high-performance windows. Visit the website at www.efficientwindows.org for more information on the studies cited in this article.


> Insulating Glass (IG)
Glass units constructed of two or more glass panes separated by a hermetically sealed space.


> Low Emissivity Coating (low-e)
Low-e coatings reduce energy transfer through insulating glass units, and thereby achieve one of the highest levels of energy performance possible for glass.


> Solar Heat Gain Coefficient (SHGC)
Measures the fraction of solar energy admitted and indicates how well the product blocks heat caused by sunlight.


> U-factor
Based on a window’s resistance to heat flow and its insulating value.


> Warm Edge Technology
The use of low- conductance spacers to reduce heat transfer near the edge of insulated glazing.


PLYGEM’S MIRA PREMIUM SERIES IMPACT CASEMENT AND AWNING WINDOW
Equipped with durable extruded aluminum cladding, HP (low-e/argon) laminated glass with a PVB inner layer, this window stands strong during the harshest conditions and can even withstand the impact of wind-blown objects. www.plygemwindows.com


SERIOUSWINDOWS 1125 SERIES FIBERGLASS WINDOW
The 1125 series exceeds Energy Star requirements by 300%, says the manufacturer. These windows are a beautifully engineered combination of frame and glass that boasts up to R-11.1 insulation. www.seriouswindows.com


39
GreenBuilder 11.2010

Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78