How Doors Can Affect Your Home’s Energy Bills

Exterior Doors

If you want to find more ways to save energy at home, start with the front door. Energy efficient doors can have a major impact on your home energy use and while it may be tempting to purchase the most stylish or affordable door, we’ve put together a few tips to help you understand and increase the energy efficiency of your doors and energy efficient products.

Are your doors energy-efficient?

Exterior doors come in a variety of materials–each with a different amount of insulation. Old-fashioned wood doors and glass doors have the least insulation. Steel and fiberglass doors are better insulators with layers of foam in their cores.

If you don’t know whether you need energy efficient doors, consider hiring a professional to audit your home’s energy use. They can give you a precise understanding of where you can get the most value by installing new energy saving doors and windows or improving your current doors.

How do energy-efficient doors benefit your home?

Door manufacturers have made tremendous advances in designing energy efficient doors that earn an ENERGY STAR® rating. In your search for an energy efficient option You can find a variety of styles and materials in energy efficient front doors that could lower your energy bill. Here are the primary benefits of energy efficient doors:

  1. Lower your energy costs. A properly installed and well-insulated door will not leak or radiate heat in the winter. In the summer, it does a better job of keeping cool air inside. In both cases, you’ll consume less energy keeping your home at a comfortable temperature.

  2. Help you earn tax incentives. You can earn an energy efficient home improvement tax credit when you replace old doors with qualified ENERGY STAR® new ones.

  3. Protect your home from the elements. Energy efficient doors do more than keep drafts down. They also keep out moisture that can lead to the growth of mold and keep insects and pests out of your home.

  4. Reduces your carbon footprint. An energy efficient door lowers your carbon footprint as you use less energy maintaining a warm–or cool–home.

Energy Efficient Options

Selecting the most energy-efficient doors

Buying energy efficient doors does not have to involve mystery. New doors that have been through testing are labeled with their ENERGY STAR rating, their U-factor, R-factor and their Solar Heat Gain Coefficient measurement.

What is the U-value of a door?

The U-value of a door is the rate at which heat transfers through the door. A well-insulated door has a lower U-value. A standard, one inch thick wood door has a U-value of .65 whereas a well-made fiberglass door has a U-value of .09, making it one of the most energy efficient doors you can buy.

A Variety of Exterior Doors

What is the R-value of a door?

The R-value measures a material’s resistance to heat flow. In the case of doors, higher is better. Energy efficient exterior doors with a high R-value will resist radiating heat, and thus provide better insulation.

Entry Door

Exterior Doors

The place where energy efficient doors matter most is on the exterior of your home. Good insulation and properly installed door weatherstripping makes a difference in regards to Exterior Doors.

  • Fiberglass doors. Fiberglass doors are among the most energy efficient and durable options. The flexibility of fiberglass means they can be made in a variety of styles and finishes. The foam core provides exceptional insulation. Fiberglass does not warp, rot or expand, which makes these doors nearly maintenance free. High end options are finished with wood veneers that give you the look of wood with the benefits of fiberglass.

  • Traditional Wood doors. Wood doors are a classic, however, they are the least energy efficient and come with high maintenance costs. They can absorb moisture and warp. Wood offers little in the way of insulation. If you opt for a wood door, also invest in a good storm door and weatherstripping

  • Vinyl doors. Vinyl doors are a low-cost alternative to wood, fiberglass or steel doors. They are lighter in weight, yet provide good insulation. Sun can break down the plasticizers, so use care where you install them.

  • Steel doors. Like other highly energy efficient front doors, steel doors use sandwich technology, wrapping an insulating foam layer within the steel. Because they are strong and do not warp, steel doors have no gaps where heat can be lost. Among the most energy efficient choices, steel doors offer extra security and sound proofing.

  • Accessory: Doggy doors. Pet doors are a great convenience, however, they can be energy sinks. Look for insulated frames and doors. Make sure the flap seals tightly, even in windy situations, to keep heat in.

Interior Doors

Most interior doors have no insulation at all. For some rooms that is fine, but you may wish to install an exterior insulated door in some interior locations, such as a door to an attic, that could be subject to drafts.

  • Solid-wood doors. Solid wood doors are beautiful and durable when used in home interiors. They are heavier than alternatives, however, and can warp under certain conditions.

  • MDF doors. Medium density fiber doors are lightweight and inexpensive, making them an extremely common interior door choice.

  • Hollow-core doors. These light and inexpensive doors have no insulation or sound proofing. Use care around them as they are not very durable.

How to test your doors

Before going to the expense of replacing an existing door with one of today’s more energy efficient front doors, you should see how well your current door is performing and if you have any air leaks in your home around it.

Save Money
  1. Conduct a visual inspection of your door’s seal. Take a look at the insulation around your door. If it is missing chunks or is hanging loose in spots, you should replace it.

  2. Check for light. On a bright day, close your door and examine the edges from the inside looking out. If you see light, you don’t have a good seal. Heat is leaking out wherever there is light.

  3. Check for drafts. Light a candle by your door on a cold and blustery day. If the candle flickers when it is near the door, especially along the floor, your weatherstripping is not doing its job.

  4. Feel the door. Again, on a cold day, put your hand against the door. If it is very cold, you have little insulation and are leaking heat.

  5. Look for signs of pest infestation. A door that isn’t closing well will let insects, mice and other pests into your home. If you see signs of pests, your door isn’t sealed well.

  6. Do a dollar bill test. Use a dollar bill and see if you can slide it under and around your front door. If you can, you are literally throwing money out your front door.

  7. Check for weakness in your door’s structure. Older doors may not hang properly or the material from which they are made could be degrading, creating gaps that leak heat.

Types of Energy-Efficient Doors

Entry doors

Your home’s front door needs to look good and do its part in keeping your house secure. There are so many options on today’s market that you’ll be able to find exactly what you want without compromising on style.

Wood exterior doors are beautiful and classic. They don’t insulate as well as steel and fiberglass doors with foam cores. If you have your heart set on the look of wood, take a look at fiberglass front doors. Fiberglass can be made to mimic almost any material, including wood.

Patio doors

Patio doors are traditionally all glass. This keeps the view to the outdoors nice and open. But since they’re all glass, patio doors aren’t as energy efficient as entry doors.

But that doesn’t mean that energy-efficient patio doors don’t exist! Energy-efficient patio doors will have many of the same features as an energy-efficient window:

  • Two panes of glass with insulating argon or krypton gas between them

  • Fiberglass, vinyl, or wood frame

  • Professional installation to ensure a tight fit

Sliding glass doors offer better energy efficiency than French doors. Keep a close eye on the seals, especially if the door receives a lot of use. The friction from sliding the door open and closed can cause the seals to wear down over the years. Worn seals decrease the door’s efficiency.

You can find energy-efficient French doors, of course. Because both doors open (as opposed to just one in a sliding door), their efficiency rating will be slightly lower than a sliding door. Replace any failing seals on your French doors promptly to reduce air leaks.

Energy efficient doors

How to Read an ENERGY STAR Label

When you buy new windows and doors, keep an eye out for options that carry the ENERGY STAR label. ENERGY STAR products reduce energy costs by an average of 12 percent over their traditional counterparts.

ENERGY STAR is a government program that identifies energy-efficient products for consumers. The ENERGY STAR label ensures that the windows and doors you are buying are truly energy efficient.

Here’s a quick guide to the terminology you’ll need to know:


The U-factor measures how well a window or door insulates your house. U-factor numbers range from 0.25 to 1.25. A lower number means that a product provides better insulation.

Low-E glass lowers a window’s U-factor. Multiple glass panes and insulating gas between the panes do the same. The U-factor measurement is important no matter where you live. But it’s especially important if you live in a cold climate.

Solar Heat Gain Coefficient (SHGC)

The Solar Heat Gain Coefficient (SHGC) measures how well a window or door blocks the heat from sunlight. SHGC ranges from 0 to 1, but you will typically find numbers between 0.25 and 0.80.

Normally, when looking for the best SHGC, the lower numbers are better. If you live in a colder climate, however, look for a higher SHGC rating. A higher SHGC means the product is better at collecting solar heat to warm your home. For warmer climates, a lower SHGC means the window or door will block heat gain to keep your house cooler.

Visible Transmittance (VT)

Visible transmittance measures the amount of light that comes through your windows. When you add more glazing to your windows, the VT decreases.

VT is measured on a scale of 0 to 1, and you will typically see values from 0.20 to 0.80. If the VT drops below 0.40, everything you see through the window may appear gray. If you want a lot of sunshine to come through your windows, choose a window with a higher VT rating. Consider your options wisely, since unfiltered sunshine can fade furniture, carpet, and flooring.

Air Leakage (AL)

The air leakage rating measures how quickly air escapes through joints or cracks in a window or door. A lower AL number equals less air leakage.

The standard value is 0.3 cfm/ft². The air leakage rating is important because openings in windows and doors can let moisture into the house. That moisture can foster mold growth and cause health issues. Properly sealed windows and doors can also save you money on heating and cooling bills.

Condensation Resistance

Condensation resistance is a measurement of how well a window resists moisture buildup. This feature is measured on a scale of 0 to 100. A higher number means that the window has a high resistance to condensation. This is a good thing, especially in wet or humid climates.

Solid Wood Doors

Proper Window and Door Installation

The best energy-efficient windows and doors are only as good as their installation. Choose your installation company very carefully. Best Pick window and door companies carry general liability insurance, state-required workers’ compensation insurance, and any required trade licenses. They also must meet our high standards for. Keep an eye out for the following signs of a less-than-stellar window or door installation:

  • A door that doesn’t hang level in the frame

  • Windows or doors that require significant force to open or close

  • A door that creaks loudly and consistently

  • An increase in your heating and cooling costs

Improper installation can cause all sorts of problems. It can also make your new doors and windows less efficient. Above all, your installer should follow the manufacturer’s installation procedures. If they don’t they’ll void any manufacturer warranties on your windows or doors. That definitely isn’t what you want.

Looking to replace your existing doors? Contact Window & Door Specialties today!

A new door can enhance the beauty and security of your home. If you make a careful choice and select an energy efficient front door, you can save enough money on your energy bill to pay for the door and its insulation.

Making decisions about your home are important and Window & Door Specialties can help make the process painless. We have 5 locations in the Carolinas. Contact us today!

Increase Energy Efficiency

Like this article?

Share on Facebook
Share on Twitter
Share on Linkdin
Share on Pinterest

Leave a comment

Join Our Mailing List for Future Discounts!