Energy Efficient Windows

Energy efficient windows are an important consideration for both new and existing homes. Heat gain and heat loss through windows are responsible for 25%–30% of residential heating and cooling energy use.
If you are selecting windows for new construction or to replace existing windows, it's important to choose the most efficient windows you can afford that work best in your climate.
If your existing windows are in good condition, taking steps to reduce the energy loss through windows can make your home more comfortable and save you money on energy bills.
You have two options if you hope to reduce the amount of energy lost through your windows and improve the comfort of your home:
Inspect and Repair Existing Windows:
- Check existing windows for air leaks
- Caulk and weatherstrip. Check out our do-it-yourself project to learn how to weatherstrip double-hung windows.
- Add window treatments and coverings. Learn more about your window treatment options.
- Add storm windows or panels
- Add solar control film
- Add exterior shading, such as awnings, exterior blinds, or overhangs.
With any efficiency improvements, take steps to ensure proper installation and check for air leaks again after making the improvement.
Replace Your Windows
If you decide to replace your windows, you will have to make several decisions about the type of windows you purchase and the type of replacement you will make.
You may have the option of replacing the windows in their existing frame; discuss this option with your window retailer and installer to find out if it will work for you.
You will also need to decide what features you want in your windows:
- Frame types
- Glazing type
- Gas fills and spacers
- Operation types
In addition to choosing the window type, you also need to consider design, energy use and labeling, warranties, and proper installation.
First look for the ENERGY STAR label when buying new windows. Then review ratings on the energy performance label from the National Fenestration Rating Council (NFRC) to find the most efficient windows for your needs.
NFRC ratings are included on all ENERGY STAR certified windows and provide a reliable way to determine a window’s energy properties and compare products. Learn about energy performance ratings for windows to understand how to read the labels and energy-use information.
Installation
Even the most energy-efficient window must be properly installed to ensure energy efficiency and comfort. Have your windows installed by trained professionals according to manufacturer’s instructions; otherwise, your warranty may be void.