When it comes to energy efficiency, windows are frequently the determining factor when selling a home or remodeling an existing one. Depending on the time of year, about 25-30% of heating and cooling energy can get lost either through heat gain or heat loss, according to the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy.
Many homeowners worry about the looming costs, but new windows could eventually end up paying for themselves in energy savings.
— What are energy-efficient windows?
— Performance evaluation of energy-efficient windows.
— How much do energy-efficient windows cost?
— Energy bill savings.
— Are energy-efficient windows worth it?
What Are Energy-Efficient Windows?
Any part of a window’s construction, from the glass to the frames, can impact its thermal efficiency. The installation, in addition to the makeup, might significantly boost performance or drastically reduce its capability.
“Energy-efficient windows, such as double or triple-pane windows, provide increased insulation compared to single-pane windows and can help lower your energy usage,” says Rupa Mehta, home expert at home services company Angi.
Energy-efficient windows were designed to prevent your home’s warmed or cooled air from escaping by increasing insulation and reducing energy use, depending on the windows you had before upgrading. They also reduce the amount of work your HVAC system has to do to keep your home at a comfortable temperature, Mehta adds.
To help consumers and businesses choose between energy-efficient windows, the U.S. Environmental Protection Agency and the Department of Energy developed a set of standards for windows called Energy Star. Energy Star reports that in 2020, products carrying the rating helped Americans reduce energy costs by $42 billion.
Performance Evaluation of Energy-Efficient Windows
When it comes to evaluating the efficiency of energy-saving windows, five criteria are used:
— U-Factor. This is the amount of non-solar heat that can transfer from outside to inside. The lower the U-factor, the better insulated the windows.
— Solar Heat Gain Coefficient. The SHGC shows how well the window blocks heat. The lower the SHGC, the higher the blockage.
— Air Leakage. This measures airflow via the window joints. A lower AL means there’s less air leakage from the window.
— Visible Transmittance. VT measures the light let through the window. The higher the VT, the higher the light transmission.
— Condensation Resistance. A window with a higher CR rating is more resistant to condensation.
In addition, the quality of the installation makes a significant impact on the effectiveness of the windows, which means that they are only a worthwhile investment if done well.
How Much Do Energy-Efficient Windows Cost?
According to Mehta, energy-efficient windows cost between $300 and $1,000 per window while traditional windows typically cost between $180 and $410 per window.
“The exact cost will depend on the size of the window, type of glass and whether or not you add upgrades like reflective coatings,” Mehta says. “Energy-efficient windows may come with a high price tag, but they also have a high return on investment at 68%.”
Labor can cost between $30 to $50 per hour, according to HomeAdvisor, but most contractors will bid at a flat rate with labor included. A basic project can take under two hours per window while complex projects, custom work and older homes may require up to six hours per windows.
A local window installer may be able to assist you with your window installation within your budget and some manufacturers may include installs and give warranties on their work.
Energy Bill Savings
The DOE compared the annual energy consumption and the annual cost of Energy Star-rated windows and less efficient models, and found significant variations. Less efficient windows double the annual energy expenditure per square foot compared to Energy Star-certified windows.
Comparing yearly energy usage (kilo-British thermal unit per square foot), they found that the least efficient windows used 174 kBtu per square foot, while those certified by Energy Star used only 137 kBtu per square foot — showing long-term savings in utility bills and a dramatic decrease in energy use.
“Energy-efficient windows can help you save an average of 12% on your energy bills. This means you’ll save between $100 and $600 per year on your utility bills,” Mehta says. “Your exact savings will depend on your climate and how many windows you have.”
When shopping for energy-efficient windows, an important factor to keep in mind is the climate.
The best option in one area, like Florida, may not be the best option in another, like Maine. This will also affect the amount you will ultimately be able to save.
Are Energy-Efficient Windows Worth It?
“Energy-efficient windows can help you save money, lower your carbon footprint, extend the life of your HVAC system and reduce noise in your home,” Mehta says. But how much you can potentially save depends on where you live and the type of windows you’re replacing.
For example, single-pane windows in rotted wood frames can be replaced with Energy Star-certified double-paned windows and new frames, which can significantly reduce monthly power costs. If you currently have double-pane windows with frames in good condition and switch to Energy Star models, you won’t see as much of a difference.
Mehta advises that if you’re on the fence, you can call a contractor you trust and ask them if energy-efficient windows would be a good addition to your home.
More from U.S. News