In fact, the majority of what a window does, or how well it performs, is unseen. These factors affect window performance and if you’re in the market to replace your windows, they are things you need to consider when evaluating your choices.
Here are the five factors that affect window performance and an explanation of each:
One: U-FactorThe U-factor measures how well a window prevents heat from escaping. The lower the number, the better insulated the window will be. High-performance, double pane windows can have U-factors of 0.30 or lower. Some triple-pane windows can go as low as 0.15. Low U-factors are beneficial for any climate as they will help keep energy costs low.
Two: Solar Heat Gain CoefficientSolar heat gain coefficient (SHGC) measures how well a window blocks sunlight. SHGC is expressed as a number between 0 and 1. The lower the number, the less heat will enter into your home. You can purchase windows with different levels of SHGC, choosing the level that to makes the most sense for your home and the position of your windows.
Three: Visible TransmittanceVisible transmittance (VT) measures how much light passes through a window. This is different than SHGC, in that VT includes spectrally selective coatings to allow different amounts of visible, infrared, and ultraviolet light to pass. VT varies between 0 and 1, with 1 letting the most light through. For reference, most modern double pane windows fall between 0.30 and 0.70.
Four: Air leakageAir leakage (AL) measures how much air escapes through a window. AL affects heat loss and gain and thus can have an impact on your annual energy costs. The lower the number, the more efficient a window will be. To have an ENERGY STAR certification, the window’s AL rating must be 0.30 or less.
Five: Condensation resistanceCondensation resistance (CR) measures the ability of a window to resist condensation on its interior. CR is valued between 1 and 100. The higher the number, the better the window’s ability to resist condensation.
Sorting through the factors that affect window performance can be a headache for most homeowners. It can be difficult to understand just which combinations at which levels will lead to the best investment. That’s why it’s critical to have a true professional at your side.
Legacy Remodeling is the Pittsburgh region’s choice when it comes to window replacement. We can help you choose the best windows for your home that will add real value to your home and create real monthly energy savings. If you are in the market for new windows, contact us today.