How to Choose Energy-Efficient Replacement Windows

How to Choose Energy-Efficient Replacement Windows

Choosing energy-efficient replacement windows is an excellent way to improve your home’s energy efficiency and potentially reduce your energy costs. Here are some factors to consider when selecting energy-efficient replacement windows.

Energy Star Certification

Look for Energy Star-certified windows. This certification indicates that the windows meet or exceed energy efficiency standards set by the U.S. Environmental Protection Agency (EPA). Energy Star windows help reduce heating and cooling costs and improve comfort.

U-Factor and Solar Heat Gain Coefficient (SHGC)

Pay attention to the U-factor and SHGC ratings of the windows. The U-factor measures the window’s insulation value, with lower numbers indicating better insulation. The SHGC calculates how much solar heat the window allows into your home, with lower numbers meaning less heat gain. Choose windows with low U-factor and SHGC ratings for optimal energy efficiency.

Window Frame Materials

Different window frame materials have varying levels of energy efficiency. Standard options include vinyl, wood, aluminum, and fiberglass. Vinyl frames are often the most energy-efficient and low-maintenance choice. Wood frames can provide excellent insulation but require more maintenance. Aluminum frames are less energy-efficient, but you can improve them with thermal breaks. Fiberglass frames offer good insulation and durability.

Multiple Panes and Low-E Glass

Windows with multiple panes and low-emissivity (Low-E) glass are more energy-efficient. Double-pane or triple-pane windows create insulation pockets that help reduce heat transfer. Low-E glass has a thin coating that reflects infrared heat, keeping the interior cooler in the summer and warmer in the winter.

Gas Fills

Some energy-efficient windows have gas fills between the panes, such as argon or krypton gas. These gases are denser than air and provide additional insulation, improving energy efficiency.

Window Orientation and Climate Considerations

Consider your home’s geographic location and window orientation when choosing replacement windows. For example, in colder climates, windows with a higher solar heat gain can be beneficial to capture sunlight and provide passive solar heating. In warmer temperatures, windows with lower solar heat gain are preferable to minimize heat gain.


Proper installation is crucial for energy-efficient windows. Even the most energy-efficient windows will only perform well only with correct installation. Ensure professionals install the windows following industry best practices to maximize energy efficiency.

Cost and Budget

Energy-efficient replacement windows can vary in cost. Consider your budget and weigh the upfront investment against potential long-term energy savings. Remember that energy-efficient windows may qualify for tax credits or other incentives, offsetting costs.

Consulting with window professionals and doing thorough research can help you select energy-efficient replacement windows for your home.