Window Efficiency 101

Window Efficiency 101

The region is heating up and warm days are here to stay across Virginia. If you’re seeking refuge from the heat and want to make sure your home stays cool, consider what you know about your home’s windows.  Are they efficient?

Many homeowners lose an estimated 30 percent of the money they spend on cooling costs due to inefficient windows. Now that’s a lot of energy waste! ENERGY STAR qualified windows, doors and skylights can help you reduce your energy use and keep your cool air inside the house.

To help you prepare for your window project, we’ve gathered some information you should know: 

Key Terms to Know:

  • The insulation in windows is measured by U-factor. U-factor refers to the rate of non-solar heat transfer through a window. The lower the U-factor, the more insulation the window provides. U-factor ratings generally fall between 0.20 and 1.20.
  • Familiarize yourself withsolar heat gain coefficient (SHGC), which measures the fraction of solar energy transmitted and tells you how well the product blocks heat caused by sunlight. SHGC is measured on a scale of 0 to 1; values typically range from 0.25 to 0.80.

Identify Materials and Contractors
Make sure the materials you choose are suited to the type of climate in which you live. Get started by determining your climate region


  • In addition to the long-term energy savings you’ll enjoy, take advantage of financial incentives that lower your initial investment. Check with your local utilities and state to see if they provide financial incentives or rebates for purchasing ENERGY STAR qualified windows.

If upgrading your windows to make them more energy efficient isn’t in your budget, you’re not out of luck! There are many ways that you can improve the efficiency of your windows and the comfort of your home with a limited budget. Check out these DIY projects to help keep the cool air inside your home.

Already taken on a project to make your home more energy efficient? Share your story with Virginia Energy Sense on our Facebook page and we’ll feature you in an upcoming blog!