Choosing your new windows requires focusing on energy efficiency. Springing for the least expensive window that you find might save you money initially, but over time you might pay in energy costs and frustration over a too-cold or too-hot house. Understanding the U-factor of a window can help you make the right choice for your region (contact us for more information).
What Is U-Factor?
When you look at new windows, they all have stickers on them telling you about all the awesome efficiency ratings that they possess. These ratings are supposed to help you figure out which window would be the best for your particular house and specific rooms in your house. One of these ratings, the U-factor, is a number that measures how heat transfers through the window which then tells you how the window does in terms of insulation. The range for U-factor values is 0.22 to 1.25, and the lower the number the better the insulation properties. Generally, the windows that are made to resist heat flow also have the best ability to insulate. This includes a lot of factors, but if heat can come into a house through the window or leave a house through the window, the window isn’t insulating very well.
U-Factor and Climate
Generally speaking, a better insulating window is important in all climates. You want to find a low U-factor rating no matter where you live. A number between 0.22 and 0.39 is ideal for cold climates. To achieve the lowest numbers of U-factor, the window needs to have three layers of glass. This makes a window more expensive, but you also might recover your costs by saving on your utility bills. In a hot climate, you still want to look for a low U-factor rating. But you probably want to also choose the very lowest rating you can find (somewhere between 0.22and 0.30). Keeping that heat out is priority!