If you are shopping for the best replacement window for your home; start by making sure it has the Energy Star label and comparing the NFRC Energy Performance Ratings. But most importantly, make sure you select the right company and the best product.
Did you know that Air Infiltration, or air leakage, is commonly overlooked because most people are not aware of air infiltration, why it’s important, or how it’s measured. The whole reason you’re shopping for new windows is probably because your current windows leak air and are drafty or have a seal failure and are foggy.
One common misconception is that when you purchase new replacement windows they will create a vacuum and not allow any air to pass through them. A window is made of many parts and all windows allow air to infiltrate, or leak into your home.
Air leakage, also known as air infiltration, is the measurement of air that passes through the window assembly itself. This number is determined before installation and in order to keep that number where it’s at, you must have your windows professionally installed so there are no drafts.
Air infiltration measures how much air a product will allow to enter a room. It is measured by how many cubic feet of air can pass through a window in a specific time frame divided by the total window area. The National Fenestration Ratings Council (NFRC) is responsible for this rating, just like it rates the U-factor and other energy performance ratings.
Looking at air leakage ratings you should see a rating between 0.1 – 0.3, with 0.1 being the least amount of air that passes through the window, meaning less drafts. You are looking for the lowest number possible since that allows the least amount of air infiltration.
Obviously, the amount of air that passes through a window is an important rating for energy efficiency. However, you should know that air leakage ratings below 0.1 aren’t even recognized by the NFRC. The reason for this is because when the numbers are that low, there’s basically no difference between one window and another.
Also, air infiltration (leakage) isn’t a required window rating yet. Some companies intentionally leave it out of their brochures and online product specifications. Home owners would do well to avoid any company that won’t even display their window’s air infiltration rating. Gerkin windows and doors are rated and certified by the American Architectural Manufacturers Association (AAMA) and the National Fenestration Rating Council (NFRC).
Remember that every aspect of your windows energy efficiency counts, especially when you’re trying to save money… and isn’t that one of the main reasons you’re replacing your windows in the first place?