It's common for people to want to have new windows installed before the cold winter weather arrives. After all, no one enjoys dealing with old, drafty windows when it's cold outside. If you want to replace your old windows with newer, more energy efficient ones, you need to learn how to interpret the various ways windows are rated. This way, you know you're purchasing windows that will keep the heat in your home and the cold weather outside.

Solar Heat Co-effciency and E-Class Efficiency Ratings

All Energy Star certified windows have an E-class rating and a solar-heat co-efficiency rating. In order to be Energy Star certified, both of these ratings need to fall at or below 0.35. That doesn't mean that either of these ratings should be important to you. However, you might want to discuss both option briefly with the salesman at your local glass company to make sure you're purchasing windows that fit all of your needs.

A window's solar heat rating indicates how well the window keeps heat out of the house. So, while it's extremely important to people who live in areas with hot climates, it's not going to be as important to someone like you, who is looking for energy-efficient windows that work well in the winter. However, even people who live in northern states get some hot weather in the summer, so keep in mind, the lower the solar co-efficiency rating, the better. The E-class rating indicates how well the window blocks harmful UV rays from entering your home. If you're replacing windows that get a lot of direct sunlight and you're concerned about UV rays coming into your house, look for windows with a E-class rating of 0.35 or lower.

The R-Value and U-Factor

When you're looking for energy-efficient windows that perform well during the winter months, you'll want to pay close attention to the window's R-value and U-factor. Windows that are designed to insulate your house well, which is what you need during cold winters, will have an R-value at or above three. The higher the R-value of a window is, the more insulation it provides.

A window's U-factor rating indicates how well the window keeps heat inside your house, which is also important to people who need windows that perform well in the winter. All windows have U-factors that fall between 0.25 and 1.25. When it comes to the U-factor, the lower the number is, the better the window performs.

Once you understand how windows are rated, it isn't difficult to find replacement windows that will help keep the inside of your home warm during the winter. If you have any questions or concerns about how different windows perform in different conditions, talk to the salesperson at your local glass company before making a purchase.