Low-emissivity (Low-E) windows feature glass that has a thin coating on the glass within its airspace that reflects thermal radiation or inhibits its emission reducing heat transfer through the glass. This coating or film allows light in, but prevents some solar rays from being transmitted through the glass.
There are many reasons why you should consider using Low-E glass windows:
Low-E glass is an energy-efficient, high performance glass. Therefore architects, builders, and homeowners have the freedom to incorporate larger window and glass areas in their designs, without the resulting excessive energy costs.
Reduce Heat Loss in Winter - Low-E glass reduces radiant heat transfer and reflects interior heat back into the room, not back outside.
Reduce Heat Gain in Summer - Low-E glass reduces the flow of hot outside air into the cooler interior of your house in the summer.
Lower Utility Bills - Low-E glass helps reduce the amount of heating and cooling energy needed to keep a house at a comfortable temperature. That means furnace and air-conditioning systems work less and that can add up to significant energy savings.
Reduction of UV Rays - Low-E glass significantly reduces transmission of the sun's damaging ultraviolet rays, one of the leading causes of premature fading and degradation of fabrics, upholstery and carpeting.
Comfort - No one enjoys sitting near a cold, drafty window in winter. Low-E glass works to raise the inside glass surface temperature in winter. This can help to minimize cold spots and keep you more comfortable.
Minimized Condensation - Low-E glass helps keep the inside glass surface temperature warmer, therefore providing a more comfortable, higher humidity level with greatly reduced condensation and fogging.
Computer software developed to calculate energy ratings can compare the heat loss of a standard thermopane to a Low-E window for Halifax’s climate. Annual savings for a window with a glass area of 1 square metre range from $9.94 if it faces south to $12.21 if it faces north. Replacing an older, less airtight window in an existing home would save much more. The chart below shows the window orientation estimated annual savings per window with Low-E glass:
|Window Orientation||Estimated Annual Savings per Window|
|North Facing Window||$12.21|
|East Facing Window||$10.62|
|Southeast Facing Window||$9.94|
|South Facing Window||$9.38|
|Southwest Facing Window||$9.94|
|West Facing Window||$10.62|
Added Resources: Link to Conserve Nova Scotia Selecting Energy Efficient Windows PDF