One of the major performance rating categories that is usually (but not always) listed on an NFRC label is Air Leakage. This measurement is sometimes referred to as “air infiltration” and measures the amount of exterior air that will pass through a window and into a home. In general, most air infiltration happens through gaps and cracks in the outside shell of a window. However, poor insulation around windows, doors, and vents can also contribute to air leakage. Because air leakage is one of the leading causes of poor energy efficiency, most home energy audits will begin with an air infiltration test.
Calculating the air leakage of a window is actually a bit complex because it takes into account both square and cubic measurements as well as wind speed. The unit of measure used to calculate air infiltration is “cubic feet per minute per square foot.” In other words, an air leakage rating tells us: how many cubic feet of air is able to pass through a window in one minute with the wind blowing at a constant speed of 25 mph divided by the total area of the window—simple, right?
All you really need to know is the lower the air leakage rating, the less air will be able to pass through the window. In order for a window to receive an ENERGY STAR® rating, it must have an air leakage rating of 0.30 or lower. While the existing windows on many homes can have air leakage ratings of 0.50 or higher, Sunrise offers high-performing replacement windows with air leakage ratings as low as 0.02 to help keep your home as airtight as possible.
For more information about how a replacement window’s air leakage rating can affect your home’s energy performance, click here to locate a Sunrise Windows dealer in your area.