Choose an energy-efficient door
Closing the door on heat loss and gain in your home should start with an energy-efficient building envelope. Doors play a significant role in how well your home is sealed, so choosing an energy-efficient model may greatly reduce your heating and cooling costs, and result in lower greenhouse gas emissions.
How to choose an energy efficient door
- Check for warping: If you have an older door, it may allow heat to leave and enter your home too easily. Examine your door to determine if there are gaps around the edges—older doors often leak air due to an uneven fit with your door frame. If you see obvious gaps, your door should probably be replaced.
- Measure door opening: Before you go out to purchase a new door, make sure to get the dimensions of the opening. Measure the width at the top, middle, and bottom, as well as the height on the left and the right. Use the smallest measurement for each.
- Lefty or righty?: Next, determine whether you would like the door handle to be on the right or the left. Keep this in mind when purchasing or ordering your new door.
- Choose an energy-efficient model: First, determine which door is right for your climate by referring to Federal Energy Management Programs' performance table for doors. Then, when you're shopping, look for the National Fenestration Rating Council (NFRC) label on your door options, which will indicate the U-factor, solar heat gain coefficient, visible transmittance, air leakage, and condensation resistance. Alternatively, you can check out the NFRC's Certified Products Directory Search to get a complete list of certified doors (hint: this page viewed best in IE7). You should also try to choose an ENERGY STAR door whenever possible, since these models are very energy-efficient.
- Remove existing door and frame: Once you’ve brought your new door home, you’ll need to remove the old door and frame. Start by removing the trim, then the door, and finally the door frame. Refer to this handy DIY door replacement guide for illustrated instructions.
- Install new door, caulking, and trim: Insert your new frame into the prepared hole, followed by the door. Fill the space between your doorframe and the wall with expanding foam caulking, which will further help to prevent air from getting around the door and into the house. Next, apply the trim.
- Be sure door is properly sealed: After you’ve added the doorknob and lockbolt, be sure that the entire door system is sealed properly so that air doesn’t escape.
Window-free exterior doors
There are several types of non-window exterior doors to choose from.
- Steel: This door option is relatively inexpensive and durable. If you choose one with a foam core, it offers an insulating R-value of R-11.
- Fiberglass: This material is somewhat more expensive than steel and offers an insulating value between R-5 and R-10. When a poly-core is added, this door's insulating performance will increase.
- Composite: Composite doors are those with a wood veneer laminated over a steel door, foam core optional. This allows you to achieve an expensive look without using a significant amount of wood. They also offer insulating values between R-5 and R-10.
- Wood: As a renewable resource, wood is a relatively environmentally-friendly material for doors, as long as it is harvested sustainably. It requires less energy to produce wood doors, as well. However, some wood does not prevent heat gain and loss as well as other door materials. Check out the Forest Stewardship Council’s registered product database to find a sustainably-harvested wood door in your area.
Windowed exterior doors
- Glass: Commonly known as patio doors, glass doors lose heat much more quickly than other types. In order to limit the heat transfer in these models, try to purchase a glass door with low-e film, multiple panes of glass, and perhaps also gas fillers. And if you install sliding glass doors, be sure to check the weatherstripping between the doors every year for wear and tear as they tend to lose their ability to insulate your door over time.
Before you buy
Try to find a door with magnetic weatherstripping. These doors create a tighter seal and further reduce heat loss and gain around the edges.
Find it! Energy efficient doors
This vinyl double door (with reinforcement) received a 0.30 U-factor rating from the National Fenestration Rating Council.
This vinyl (with reinforcement) glass sliding door was rated 0.31 by the National Fenestration Rating Council.
This aluminum/wood composite double door received a U-factor rating of 0.33 by the National Fenestration Rating Council.
This wood door received a U-factor rating of 0.27 according to the National Fenestration Rating Council.
This swinging wood door was rated 0.15 by the National Fenestration Rating Council.
This swinging fibreglass (wood frame) door received a 0.16 U-factor rating by the National Fenestration Rating Council.
Choosing an energy efficient door helps you go green because…
- It reduces the heat loss and gain of your home’s exterior envelope, which ultimately lowers energy consumption and greenhouse gas emissions.
Close to one-third of the heat loss and gain experienced in a home is through doors and windows. Choosing doors that fit properly in doorframes and ensuring that they are made of energy-efficient material can greatly reduce heating and cooling costs.
Doors are available in a variety of materials, from fibreglass and steel to solid wood and bamboo, each varying in insulating ability. Insulated doors perform better when it comes to heat transfer than non-insulated ones, achieving R-values between two and seven. By contrast, uninsulated doors, including all wood doors, average R-values closer to one. In fact, a window-free door that's 1.5 inches thick is five times more insulating than a solid wood door.
Whether or not a door contains a window will also affect its insulating value. Doors with windows generally perform poorly compared to non-windowed doors since glass is a poor insulator.
Tax breaks and subsidies
In the US, the purchase of an energy-efficient door may qualify you for tax breaks at the federal, state, or local levels. For detailed information, see these resources:
- American Council for an Energy-Efficiency Economy Updates on potential energy legislation.
- Tax Incentives Assistance Project Explains federal tax credits for energy efficiency.
- Alliance to Save Energy Offers an index of energy efficiency programs by state.
- Database of State Incentives for Renewables & Efficiency Provides information on state and federal incentives.
- Contact your utility provider for information on local offers.
Related health issues
- air leakage: This indicates the equivalent cubic feet of air passed through a square foot of door area. The less air that passes through, the lower the air leakage rating of the door.
- condensation resistance: The measurement of a door’s ability to resist condensation formation on its interior surface. The greater its ability to resist condensation, the higher its condensation resistance will be.
- formaldehyde: A flammable reactive gas belonging to the VOC family of chemicals. It is widely used in personal care products, building materials, insulation, and home furnishings. Ingestion of the chemical can cause severe physical reactions, including coma, internal bleeding, and death. The US Department of Health and Human Services considers it a probable human carcinogen.
- gas fill: Inert gases are often inserted between panes of glass in order to improve the insulating performance of windows and doors with windows. Most commonly, these products use argon and krypton.
- solar heat gain coefficient (SHGC): Solar heat can be admitted through a door or window either by direct transmission or through absorption. SHGC measures the fraction of heat caused by sunlight on a scale between zero and one, smaller numbers indicating lower levels of heat transfer.
- R-factor: The R-factor (also known as R-value) indicates the insulating value of a product, or put another way, the product's resistance to heat flow. The higher the R number, the higher its insulating effectiveness.
- U-factor: The inverse of the R-factor, U-factor measures the rate of heat gain and loss. With values ranging between 0.20 and 1.20, the higher the U-factor the less the product is able to resist heat flow (i.e., the worse its insulating ability).
- visible transmittance: Measures the amount of visible light allowed to pass through a window. The higher the visible transmittance number (between zero and one), the greater amount of visible light transmitted.
- ENERGY STAR - Anatomy of an Energy Efficient Window & What Makes a Door Energy Efficient?
- National Fenestration Rating Council (NRFC) - Ratings Program Participant List
- Window and Door Manufacturers Association
- US Department of Energy - Exterior Door Selection and Installation
- Energy Information Administration - Energy Efficiency: Residential/Commercial
- Home Improvement Ideas.net - The Benefit of Energy Efficient Doors
- New York Department of State - Windows and Doors
- BuildingGreen.com - Green Product Sub-category: Metal Doors and Frames
- PowerHouse - Saving Energy: Windows & Doors
- US Department of Energy - Exterior Door Selection and Installation
- Window & Door Manufacturers Association
- Green Home - Toxipedia
- The Green Guide - Wood Furniture: The Problems
- US Department of Energy - The R-Value of Insulation