Energy-efficient windows are windows that reduce heat gain and heat loss in your home, lowering your energy use and costs. According to the U.S. Department of Energy, heat gain and loss through windows are responsible for 25% to 30% of residential energy use for temperature control.
You can make modifications to your existing windows so they’re more energy-efficient, or you can also replace your existing windows with more efficient models certified by Energy Star, an energy-efficiency program run by the U.S. Environmental Protection Agency and the U.S. Department of Energy.
Certain windows are more effective for different climates and homes. The best energy-efficient windows for your home are certified efficient, specific to your local climate, properly installed and fit your budget.
» MORE: Best window companies of 2025
What makes a window energy efficient?
Energy-efficient windows are better than standard windows at preventing heat gain and heat loss in the home. Here are a few features that make a window more efficient:
- Multiple panes, either two or three.
- Low-emissivity (Low-E) glass coatings.
- Insulating frame made materials such as vinyl, wood and fiberglass.
- Spacers in between panes.
- Gas fill in between window panes for insulation.
Energy-efficient windows come in a variety of frame materials and types. EfficientWindows.org, recommended by Energy.gov, has an online window selection tool to help you find the right type of window for your home. For example, our editor lives in the San Francisco Bay Area, CA and the tool suggested “ENERGY STAR zone: South-Central.”
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How to make existing windows more energy efficient
The U.S. Department of Energy suggests several ways to prevent your windows from causing heat gain and heat loss without replacing the entire window. Here are a few tactics that might be more affordable than new Energy Star-certified windows:
- Check for air leaks. You can inspect door and window frames yourself for cracks and gaps, or you can set up a home energy assessment with a professional. If you can rattle a window or see daylight around the frame, it may have an air leak. You can also conduct an at-home building pressurization test; Energy.gov has a basic tutorial available online.
- Caulk or weatherstrip. If you do find a leak, you can seal the crack yourself. Apply weatherstripping on movable components, such as a door frame or operable window (those that open and close). You can apply caulk on windows that don’t open. Energy.gov has an online tutorial on how to weatherstrip double-hung windows.
- Add interior or exterior window coverings. There are over a dozen options available, including glass film, blinds, shutters, solar screens and storm window panels. Depending on the type you choose, the right covering can reduce the amount of sunlight or wind that enters your home. An awning or overhang may be more costly to install but can reduce a significant amount of heat gain.
Choosing energy-efficient windows
There are several factors to consider when choosing new windows to increase your home’s energy efficiency. Compare windows that are specific to your climate and are Energy Star-certified.
Energy efficient certifications
As previously noted, Energy Star is a government-run energy-efficiency program. According to the program website, replacing single-pane windows with Energy Star-certified windows lowers household energy bills on average by up to 13 percent.
Energy Star-certified windows must be manufactured by an Energy Star partner. The windows must also be independently tested and verified by the National Fenestration Rating Council (NFRC), which gives the product a rating that meets EPA guidelines.
When shopping for new windows, look for “ENERGY STAR” and “NFRC” labels. The NFRC website has a guide to understanding their labels and what numbers you should be looking for.
Climate
EnergyStar.gov has a Climate Zone Finder that can tell you the eligibility requirements for energy efficiency for windows in your state and county. Different regions of the U.S. have different requirements that are tailored to their climate factors.
Where to purchase energy-efficient windows
You can purchase Energy Star-qualified windows through retailers, such as Home Depot, and many window companies. EnergyStar.gov also offers a product finder tool online where you can sort by climate zone, window type, frame material and partner company.
How much do energy-efficient windows cost?
Energy-efficient windows cost between $150 and $2,000+ per window, with most people paying around $400 per window, according to home services website Angi. Professional installation usually costs an additional $100 to $300 per window.
How to pay for energy-efficient windows
Your window company may offer some financing options (either through a partner or a payment plan), but there are other — and maybe better — financing options available.
Personal loan
Many banks, credit unions and online lenders offer personal loans, with amounts typically from $1,000 to $100,000 and with fixed annual percentage rates. You receive a lump sum and repay it in equal monthly installments over a set period, typically two to seven years. Unlike with home equity financing, there is no collateral. This means your home isn’t at risk if you miss payments, but you’ll still have to pay late fees and the late payments can negatively impact your credit. Here are NerdWallet’s picks for the best home improvement loans.
Home equity loan or HELOC
Home equity loans or home equity lines of credit (HELOC) may have lower interest rates than financing with an installer, as well as future opportunities for refinancing and possible tax benefits.
With a home equity loan, you receive a lump-sum payment and then pay it back at a fixed interest rate over an agreed period of time, typically five to 30 years. HELOCs are more akin to a credit card, something you use as needed. You’ll usually have 10 years to draw from the line of credit, during which time you only have to pay interest, and after that you pay both the principal and interest. HELOC interest rates typically are variable, meaning your monthly payment could rise or fall over time. And with each of these options, you're using your home as collateral.
Credit card
Credit cards are an option for lower cost repairs or renovations. That’s because credit cards typically charge higher interest rates than home equity loans, HELOCs and personal loans. When used responsibly, credit cards can come with great benefits, such as 0% introductory APR periods that allow you to avoid interest for a set number of months; rewards so you can earn cash back, travel or points; and sign-up bonuses that can give you some extra cash back or rewards for a larger purchase. If you go this route, you’ll want to make sure you pick one of the best credit cards for home improvements.
Which financing option is best for me?
The best financing option for you will depend on how much money you need, when you need the money, what project you’re doing and how long you need to pay the money back. New windows cost $300 to $2,500 each, depending on the kind of window you choose. For a house with 20 windows, that equates to about $6,000 to $50,000.
Since replacing all of the existing windows in your home could add value to your home, a HELOC or home equity loan may be your best option because the value of your house could increase by more than the amount of the loan. Just be aware that most HELOC or home equity lenders often have a minimum initial draw — $15,000 for example — so using your equity may not be the right solution for a lower cost window project. A HELOC makes sense when you plan to do multiple projects over many years, like replace the windows this year and paint in two years.
If it’s a less expensive window replacement like one broken window, a credit card is probably your best option if you want to pay no interest or earn rewards. Personal loans can apply to both small and large window purchases, and they may make sense if you don’t have much equity in your home.
Some window companies offer their own financing options. Before taking this option, shop around and see how their offer compares with other loans.
Regardless of what you choose, make sure you compare interest rates, terms and fees with any financing options you’re considering. This will ensure you get the best deal.
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- 1. U.S. Department of Energy. Update or Replace Windows.
