Air leakage is a critical factor to consider when selecting your new windows and the contractor who will install them. This factor is just as critical as the U-factor and solar heat gain coefficient of the window. Heated or cooled air can escape from your living space through air leaks around your doors and windows, causing your energy bills to skyrocket over time.

One of Seattle’s best window companies, Renewal by Andersen® of Seattle addresses air leakage and why it’s vital to test the energy efficiency of the window replacement you’re considering purchasing.
What Is Air Leakage?
Air leakage or air infiltration refers to the amount of air that passes through a window unit. This number should preferably be determined prior to installation, and in order to maintain it, qualified workers must install your windows. On a scale of 0.1 to 0.3, the amount of air that leaks through the window assembly is measured, with 0.1 representing the least amount of air that leaks.
Prior to installing double-hung, sliding or casement windows, it is necessary to ascertain the rating. Note that certain window manufacturers may misread the rating by contrasting different-sized windows. Additionally, it’s worth mentioning that air infiltration values are calculated with a 25 mph wind speed.
Why Does the Air Leakage Rating Matter?
When air leaks through windows, the average home’s cooling and heating costs can increase by up to 30%. Choosing the correct window, with an air infiltration value of less than 0.3, will therefore help you save money in the long run.
However, not all windows display their ratings. Occasionally, the NFRC will not recognize ratings less than 0.1. This is because windows with low air leakage ratings may lack distinguishing characteristics.
When it’s time to replace your windows, call Renewal by Andersen® of Seattle! We provide a variety of energy-efficient casements, double-hung, and bay windows. Give us a call at (206) 970-8976 or fill out our contact form to schedule a free consultation. We work with residents in Seattle and the surrounding areas.