Replacement window manufacturers, like any other specialized group, have their own language — a lot of different jargon that gets tossed around and can often end up lost on your average layperson. But Renewal by Andersen of Long Island is committed to making your replacement window experience as convenient as possible, so today we’re going to discuss one of those terms you may not be familiar with— U-Factor (and its related cousin: R-Factor). We will talk about what U-Factor us, what it means for your replacement windows, and a few other similar terms as well.
Put simply, the U-Factor is a rating system developed by the National Fenestration Rating Council (NFRC) that measures the amount of heat that is lost through windows. The best-rated windows are the ones that have the lowest U-Factor, because they lose the least amount of heat. If you’re a homeowner, you’ve probably encountered a similar rating system when dealing with insulation: R-Value. R-Value measures insulation’s heat resistance, so unlike U-Factor, a higher R-Value rating is more desirable.
When dealing with replacement windows, the U-Factor is extremely important. It is the only fully objective way to compare energy efficiency between two different windows. The ratings go from 0.10 (the best rating) to 1.20 (the worst rating). Armed with this information, you’ll immediately be able to tell which windows will be the most efficient.
U-Factor isn’t the only rating that the NFRC has created a system for, and there are a few other common factors that anyone looking into replacement windows should be aware of. The Solar Heat Gain Coefficient is one of them— it measures how much heat from the sun a window blocks. This is important in summer to keep out summer heat and lower your air conditioning bills. Its scale measures from 0 to 1, and a lower rating indicates a better window. Another rating is from Visible Transmittance (VT), how much light comes through a window. Like Solar Heat Gain, it is measured from 0 to 1, though for VT, a higher rating is desirable, as it indicates a window that is good for day lighting.
Two more ratings systems that aren’t required by the NFRC are Air Leakage and Condensation Resistance. Air Leakage measures how much outside air comes in through a window. It is measured from .1 to .3 and a lower number indicates that less air will be let in. Finally, Condensation Resistance, how well a window resists the formation of condensation, is measured from 1 to 100, and a higher number indicates a better product.
Looking for more information? As a subsidiary of Andersen Windows, Renewal by Andersen of Long Island has been providing people with quality windows in all shapes and styles for generations. Our experienced design consultants will be happy to provide you with any information in order to help you make the right decision regarding your replacement windows. Call us today at (866) 609-5033 for a free design consultation.
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