While most of us probably equate cold and drafty homes with old windows or inadequate insulation, we may not realize that doors may be to blame. The doors in our homes play an essential part in maintaining (or neglecting) the energy efficiency of our homes. According to the California Energy Commission, doors are responsible for up to 11 percent of all air leaks in a home, despite representing a relatively small amount of the total walls space. Even if a door is exceptionally well-sealed, heat transfer is bound to be a problem due to the relatively low amount of insulation in doors and door frames.
Investing in the best energy efficient doors is a cost-effective way to increase the energy efficiency of your home. It also improves the aesthetics of your home facade. And if you aspire to meet the standards of Passive House, energy-efficient doors are a must.
Weatherproofing Strategies
Before tearing out every door in your home and installing one of the most energy-efficient options on the market (which we will review below), it’s worth investing in a weatherproofing strategy. Weatherproofing for your door is an inexpensive option that is also an immediate energy efficiency upgrade. To weatherproof the doors in your home, consider using weather stripping around your door frame. Air leaks tend to occur wherever two different construction materials meet. Simple caulking (formaldehyde-free, if possible) can be applied where the door frame meets your interior and exterior walls to prevent air leaks.
You can replace your door sweep, which is designed to seal a small gap between the bottom of the door and the threshold of your floor. Wood options for a door sweep can blend in with your existing door. Making a door snake, or a weighted fabric tube that is placed at the bottom of your door can also help to keep out drafts.
These weatherproofing strategies can certainly help reduce the energy loss from your doors; however, a new door is worth considering. According to the United States Department of Energy, new exterior doors fit and insulate better than older doors. Replacing older doors in your home often result in a lower heating and cooling bill. If you’re building a new home, you should consider buying the most energy-efficient doors possible.
What to Look for in Energy Efficient Doors
Energy-efficient doors come in a variety of styles and designs, though all will share specific characteristics and performance qualities. When searching, consider some of the following features:
Door Material
Different materials for both doors and door frames offer both advantages and disadvantages. Wood doors and door frames are the most natural option and usually have the lowest embodied energy footprint. Solid wood doors also have a higher R-Value than uninsulated metal and fiberglass doors, offering better insulation capabilities. However, these types of doors and door frames are prone to warping or drying out over time. It can lead to cracks and gaps that let drafts into your home and thus compromise the thermal performance of your house.
Solid wood doors also have a higher R-Value than uninsulated metal and fiberglass doors, offering better insulation capabilities. However, these types of doors and door frames are prone to warping or drying out over time. It can lead to cracks and gaps that let drafts into your home and thus compromise the thermal performance of your house.
Fiberglass and steel doors, on the other hand, tend to have a higher embodied energy footprint than wood, but can be manufactured to limit the possibility of drafts occurring. Fiberglass is durable and lightweight, thus minimizing the likelihood of the door pulling away from the frame and causing drafts to occur. Similarly, because of the strength of steel, doors manufactured from this material can be made hollow to be filled with some insulation material subsequently. In terms of insulation values, a solid wood door that is 1 3/4" thick is expected to have an R-value of 2.17. A 1.5" to 2" metal door insulated with polystyrene insulation is calculated to have an R-value of anywhere between 6 and 7.
Glass Inserts
Many homeowners find that installing glass inserts to particular doors in their home can enhance the beauty of the door while also increasing the amount of natural light. Single-pane glass inserts, however, can significantly reduce the energy efficiency of your door, even if it is well-sealed and protected against drafts. An insulated metal door might have an impressive R-value of 7. Single pane glass inserts that are about one-fourth inch thick would have an expected R-value around .90. It dramatically reduces the thermal performance of the door.
If you do want a door that allows for natural lighting, opt for double-pane (or triple pane) inserts that are argon filled. Argon-filled inserts can at least double the insulation properties. Prioritizing Low-E glass can also improve the performance of the door. This type of glass improves the insulating properties of windows in the home through a coating that can reflect infrared and ultraviolet (UV) radiation. This will keep the hot sunlight from entering your home during the summer while keeping the heated air inside your home during the winter.
Insulation and Framing Options
Solid wood doors, as their name implies, have no extra insulation on the inside, as they are made from solid pieces of wood. While thicker doors do offer a unique aesthetic coupled with decent insulation capabilities, this door option is often beyond the budget of most homeowners. Hollow-core doors made from fiberglass, steel, or composite wood veneer, are usually much less expensive. Due to their lightweight and thin nature, however, these types of doors would offer virtually no insulation value if they were left hollow. One of the best materials to fill the large hollow space within the door is insulating foam, which increases the R-value of the door without adding significant weight.
Solid core doors are made with wood veneers that are glued over a solid core of composite or engineered wood. These types of doors are usually less expensive than solid wood options, though they offer similar insulation properties. Because they are made from manufactured wood, they are less prone to shrinkage and warping from exposure to the elements. Be sure to look for solid core doors that don’t rely on formaldehyde as a bonding adhesive.
Lastly, some of the most modern doors on the market come with improved door frames that incorporate magnetic strips around the door frame. Pieces of metal in the door adhere to that strip, creating a tighter seal and further reducing the possibility of drafts and leaks.
Our Picks for the Most Energy Efficient Door Manufacturers on the Market
While there are hundreds of companies producing top quality doors that prioritize energy efficiency considerations, some of the top manufacturers recognized by the Energy Star certified include:
Therma Tru Doors
Therma Tru Doors manufactures a wide range of energy-efficient door styles that contain a polyurethane foam core, energy-efficient glass, and weather stripping components. The weatherstripping components help to create a tighter seal and reduce air leakage around the edges.
ProVia Fiberglass Doors
ProVia Fiberglass Doors specializes in fiberglass doors that are 2.5 “thick to allow for extra insulation. Their doors also include a dual perimeter seal, which seals on the door and frame to make the door more energy efficient.
Global Windows and Doors
Global Windows and Doors is another company offering a wide range of doors made from wood, fiberglass, steel, and other materials. Their line of steel doors are made from finger-jointed knot-free pine stiles and rails for strength and durability with 24 gauge steel and HCFC free polyurethane foam insulation.
Groke Aluminum Doors
Groke Aluminum Doors is a German manufacturer of aluminum doors, makes custom entry doors that qualify as Passive House doors. Their doors are super insulated and tightly sealed, with U-Factor ranging 0.13 to 0.257. Their U.S.-based office is located in Charlotte, North Carolina.
Hammer & Hand Doors
Hammer & Hand Doors are made in Portland, Oregon. Hammer & Hand custom manufactures wood doors that are also built to the Passive House standard.
It doesn’t matter your choice in manufacturers. It’s important to remember that the doors in your home can significantly impact the comfort and energy efficiency of your home — so don’t forget about them!
