How Doors and Windows Affect Your Home’s Energy Use


Windows and doors probably aren’t the first things that come to mind when you think about reducing your energy consumption, but they can make a big difference. After all, doors and windows essentially create holes in your home’s insulation. If they aren’t built with the right materials and properly installed, they can create gaps for heat to move in and out of your home.

With soaring energy prices and concerns about carbon emissions, it’s increasingly important to make sure your home is energy-efficient. Doors and windows are prime suspects in energy loss, and installing modern options can help you save money, reduce your carbon footprint and increase the value of your home.

How Do Doors and Windows Impact Your Home’s Energy Use?

First, let’s go over what makes doors and windows such troublemakers when it comes to energy loss.

For starters, they come in a wide range of materials and styles, and some are more insulating than others. Wood and glass doors, for example, are common in older homes, but they aren’t very good insulators. Modern doors tend to use materials like fiberglass and steel and include foam layers in the cores. This design is much more effective. Similarly, windows can now be designed with special glazes or treatments to reduce the rate of heat transfer.

In addition to materials, doors and windows rely on proper installation. If the space where a window or door frame joins with the siding starts to deteriorate or warp, it could create a gap that lets air in or out. Doors also need good weatherstripping — the material along the edge of a door that forms a “seal” when it closes. If the weatherstripping becomes worn or torn or the door warps, gaps could become apparent.

Lastly, doors and windows are constantly battling the elements. They need to stand up against moisture, heat, ice and everything in between. These threats can more quickly deteriorate the material, especially around frames, and cause problems down the road. Glass windows — including small windows in doors — also guide sunlight into your home. Ultraviolet (UV) light can introduce unwanted heat in the summer. Heat gain and loss through windows alone account for over a quarter of heating and cooling energy use in residential settings.

Keep in mind that these problems affect energy use in both hot and cold climates. In either case, doors and windows serve as barriers to keep heat in or out, so your home’s heating and air conditioning systems don’t need to work as hard. In the summer, energy-efficient components can keep the hot air out and the cool air in. Of course, in the winter, the opposite happens.


The Benefits of Energy-Efficient Doors and Windows

People turn to these products for many different reasons. The benefits of energy-efficient windows and doors include:

  • Lowering energy costs: Since your heating and cooling systems don’t need to work as hard, you can save big on your energy use. The Office of Energy Efficiency & Renewable Energy says that about $200-$400 of the average American’s energy spending could go to waste from drafts, air leaks and outdated heating and cooling systems. On a long-term scale, you could also save money by extending the life span of your heating, ventilation and air conditioning (HVAC) equipment. You might get more bang for your buck by making it last longer.
  • Getting tax incentives: Energy-efficient homes often qualify for a host of tax benefits. With qualifying ENERGY STAR® products, you can offset the cost of your investment. Qualifying doors are eligible for a tax credit of 10% of the cost of the product or a $500 total lifetime credit. Qualifying windows are eligible for a tax credit of 10% of the cost of the product or a $200 total lifetime credit.
  • Reducing your carbon footprint: We’re all well-aware of the need to reduce our carbon footprints. Energy-efficient doors and windows can help you do your part for the planet and limit carbon emissions from your heating and cooling systems.
  • Protecting your home from the elements: Energy-efficient doors and windows rely on having a good seal, which also means they’re good at keeping moisture out of your home. Since moisture can lead to pests and mold, blocking it can help keep your home in good condition.
  • Increasing home value: Buyers look for energy efficiency in their homes. Upgrading windows and doors can be a great investment to help you boost the value of your home. They offer a great return on investment.

What Makes Doors and Windows Energy-Efficient?

Buying energy-efficient windows and doors is a little more detailed than looking for “energy-efficient” somewhere on the packaging. However, ENERGY STAR® certification is an excellent start. This certification comes from the U.S. Environmental Protection Agency (EPA) and is only given to products that meet specific performance and energy savings standards. Plus, they include a label with important details about the performance of your product.

The main values you’ll want to look for on an ENERGY STAR® or product label include:

  • The U-factor: A U-factor, sometimes called a U-value, reflects the product’s heat transfer rating. It provides a measurement of how quickly heat transfers through the door. A lower U-value indicates better insulation.
  • Solar heat gain coefficient (SHGC): The SHGC shows how well a product resists unwanted heat absorption. In other words, it tells you how much heat bounces off the window or door instead of moving through it. The lower the value, the more energy-efficient the product is.

You might also see values for measurements like visible transmittance — how much light moves through a window — and air leakage, or how much air seeps through a product. You can also find energy certifications from other organizations like the National Accreditation and Management Institute (NAMI) and the American Architectural Manufacturers Association (AAMA).

Here are some other elements of a door or window that can contribute to its energy efficiency.


Weatherstripping helps to limit airflow at the edges of a door by providing a “seal” between the doorframe and the door. It allows doors to serve their purpose of opening and closing without requiring space between the door and frame. Plus, some doors change shape over time. They might warp or become damaged, and weatherstripping is more flexible. It might be made of a material that can change shape with the door, such as fibers or rubber.

The best approach is to start with good weatherstripping. Not all doors have high-quality weatherstripping, which can cause the weatherstripping to wear more quickly and lose its efficacy.


Emissivity is another measurement of how heat transfers through a window. A low-emissivity or low-e window has a special coating to reduce heat transfer. It’s virtually invisible to us, so natural light can still pass through the window.

There are several different kinds of low-e coatings. In general, they increase the insulation capabilities of the glass. They’ll reflect heat back to whichever direction it came from — whether that’s the warm air generated by your HVAC system or the sweltering summer air. Look for low-e on both full windows and doors with built-in windows.

UV Coatings

UV rays can heat up the inside of your home and cause damage to flooring and furniture. Fortunately, coatings are available that can significantly reduce how much of this UV light gets through a window. Along with emissivity, a UV coating is especially important for glass doors — like patio and sliding doors — because they cover such a large area.

Storm Doors

If your exterior door isn’t very insulating, a storm door provides a second layer of protection. It can block drafts and insulate an exterior door by creating a small pocket of air between the exterior door and the storm door. You don’t always need one, but they can help provide insulation if your exterior door doesn’t cut it.

Another benefit of storm doors lies in the name. They offer added protection when bad weather strikes and help keep your exterior door in good condition.



Different materials have different insulation performances. Older wood doors might look beautiful, but they’re heavy, high-maintenance and made of one of the least-insulating materials out there. Metal and stainless steel are super durable, but they aren’t very good at insulating, either.

The best option for insulation is fiberglass. It is durable, virtually maintenance-free and very insulating. Fiberglass comes in a wide range of styles and can even be used with wood veneer to look just like an old-fashioned wood door without the drawbacks.

Number of Panes

Double-paned windows add a second layer of glass. They’re more energy-efficient than single-paned windows and can even help block out more sound. Some manufacturers even put argon gas between the panes to improve insulation.


While there are many things to look for in the product itself, you also need to consider its installation. Improper installation can easily create problems, such as gaps between a window or doorframe and the siding. Always work with a reputable and certified installer you trust to bring energy efficiency to your home or business.

How to Tell if You Need New Doors

Unless you can see your mail carrier through the cracks in your door, it might not be completely obvious that your door is hurting your energy bill. To check for efficiency problems, try to:

  • Inspect it for damage or gaps: Of course, sometimes you can see very clear issues. Take a close look at the door for deterioration or gaps. Your door may have warped or chipped areas, leaving spaces for air to flow through. Your weatherstripping could also have worn or torn over the years. Look for problems with the door’s structure, too, such as a door that hangs crooked off its hinges.
  • Check for light: Similarly, shut your door on a bright day and inspect the edges. If you see some light leaking through, the air is probably getting through, too.
  • Check for drafts: On a windy day, light a candle or incense stick and hold it around the edges of your door. If it flickers, you likely have a problem. You can also get more advanced by closing all doors and windows and turning on your exhaust vents. Doing this creates negative pressure inside the house, so air gets sucked in from any openings — i.e., leaks. Grab your candle or incense and hold it around your door, looking for any movement.
  • Check the temperature: Pick a cold or hot day and feel the door. If it’s closer to the temperature outside — cold in the winter or hot in the summer — it may not be very well-insulated.
  • Look for pests or mold: If you see any of these around your door, you probably don’t have a good seal.

You generally don’t need to worry about the insulation properties of interior doors, unless they lead to areas like attics or garages that are exposed to hot or cool temperatures.

How to Test Windows for Energy Efficiency

Testing the performance of windows is a little trickier because the glass itself is usually a culprit. Here are some ways you can test your window’s energy efficiency:

  • Look for disintegrating caulking: Caulking seals up gaps between the window frame and your siding. If it’s in bad condition, it could create spaces for air to move through.
  • Look for damaged glazing: Glazing is a putty used to hold window panes in place. If the glazing is cracked or dry, it could be letting air and moisture in.
  • Check for drafts: Use the same technique we mentioned for doors to see if your windows let in drafts.
  • Use an infrared laser thermometer: If you have a professional audit your home, they might use an infrared system to create a heat map of how temperatures move through your window. With an affordable infrared laser thermometer, you can conduct your own test. Pick a day where there’s a big difference between outside and inside temperatures. Grab the temperature from somewhere in the house, then take the temperature of your window. If the difference is high, you probably have a leak or inefficient windows.
  • Use a U-value kit: These kits have sensors you can place on either side of your window. They connect to a data logging device, which links up with your computer. Then, you can read the measurements to find the window’s U-value and understand how well it transfers heat.

Buying and Installing Energy-Efficient Doors and Windows

If you find that your doors and windows aren’t up to par, it’s probably time for a replacement. Installing new doors or windows can improve energy efficiency in many ways. Always look for ENERGY STAR® ratings on your product and have it installed by an experienced, reliable professional.

For homeowners in northern Virginia, Sunshine Contracting is your source for energy-efficient windows and doors and installation. We’ve been committed to quality since the ’90s and have built up a long list of certifications and affiliations with industry-leading organizations. Whatever you have in mind, we can help you bring it to life with energy efficiency at the front and center. Our capabilities include entry doors, sliding doors, storm doors, an array of window styles and much more.

Reach out to us today to schedule a free quote or chat with a pro about making your home as efficient as possible.

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