Everything you need to Know about Exterior Doors

The exterior doors of homes have long played an essential part in architectural history. From the significance of front doors for the Jewish Passover festival to the elaborate doors of castles adorned with aristocratic families' crests, exterior doors are a defining feature of the homes we inhabit. The exterior cladding, landscaping, and other features can certainly draw attention, but exterior doors act as a passageway and introduction to the buildings we live in. 

Choosing the best exterior door doesn't only help draw attention to the attractiveness of your home but can affect your house's energy efficiency and thermal performance. Unfortunately, many door manufacturers focus on the aesthetic qualities of the exterior doors that they make while disregarding the efficiency qualities these doors should incorporate. Because exterior doors connect our home to the outside world, energy efficiency measures are of the utmost importance.

We have looked over hundreds of exterior doors offered by dozens of manufacturers. What follows is a complete review that will help you choose the most eye-appealing doors that are functional, energy-efficient, and practical for your household needs.

Of course, a back patio door can be designed to drastically increase your home's living area by connecting the house to an outdoor living space. Even for tiny homes, an extra door can be designed to open up to a connected greenhouse, which increases the home's insulation while offering the opportunity to grow your vegetables.

There are different standard dimensions and features for the varying types of exterior doors, which include:

• Front door: The International Residential Code states that the minimum width for front doors should be at least 32 inches wide and a minimum of 78 inches high. These dimensions hold for all exterior doors. However, front doors are usually thicker than other doors and have a standard thickness of 1 ¾ inch. According to the U.S. Department of Energy, the standard insulation value for exterior doors is between R-5 and R-6. Insulation values can be much improved for colder areas, as we will see below.
• Back door and side doors: Back doors and side doors often lead to garages or alternative entrance or exit ways to the home. They can be smaller than a front door, with a minimum width of 30 inches. If the door connects to another home attachment, such as a garage, they can have lower insulation values. However, if they connect directly to the outside, they should maintain the minimum R-value of 5 or 6 as recommended by the U.S. Department of Energy.
• Patio door: Patio doors can be anywhere from 30 to 36 inches in width. Frequently, homeowners will prioritize double doors that lead into enclosed patios or sunrooms. When positioned or oriented correctly, patios can take advantage of passive solar design, capture the sun's warmth during cooler times of the year, and add natural heat and light to the home.

Which Exterior Door Is Best?

There are hundreds of different types of exterior doors on the market. How can homeowners make an educated decision about which kind of door is best for their particular needs?

The United States Department of Energy states that "your home's exterior doors can contribute significantly to air leakage, and can also waste energy through conduction, especially if it's old, uninsulated, improperly installed, and/or improperly air sealed. Weatherstripping can reduce energy losses due to air leakage."

When searching for the best exterior door, then, the following criteria should be taken into consideration:

• Energy Performance Ratings: The energy performance ratings of different types of doors (and windows) will help homeowners find the best exterior door for their specific climate and home design. The National Fenestration Rating Council (NFRC) has a label that is easy to read and understand. Homeowners can use this label to determine and compare the most energy-efficient types of doors on the market and narrow down your decision to the best energy efficient entries for your specific context.
• Energy Star Doors: The U.S. Government Energy Star Program rates the most energy-efficient doors currently on the market. This program looks explicitly at exterior doors incorporating large amounts of glass and rate doors based on the solar heat gain coefficient (SHGC) and U-factor for the door. Homeowners who want exterior doors to allow light to flood into their home should search for glass doors with a low SHGC rating in hot climates and a high SHGC when their home is located in a cold environment. In addition, the lower the U-Factor on the Energy Star rating, the better the door will be able to slow heat flow into or out of your home.

How to Install Weather Stripping On an Exterior Door?

No matter what type of door you have, weatherstripping your doors and windows should be a priority. There is no better way to quickly and cheaply stop air leaks and improve your home's energy efficiency than by purchasing a DIY weatherstripping kit for your doors and windows. The National Renewable Energy Laboratory (NREL) estimates "that caulking and weatherstripping any gaps will pay for itself within one year in energy savings."

For homeowners who do not want to invest in new exterior doors, weather stripping can significantly improve the performance of even the oldest of doors. To weather strip an old door, you will first want to remove the old weather stripping. Caulking and other sealants (VOC-free, if possible) only require an inexpensive caulking gun and a steady hand. More advanced options include a rigid aluminum bar and a rubber gasket. You might have to use a hacksaw to cut the aluminum weatherstrip to the right size before attaching it with screws to the door's bottom exterior surface. You can use the same aluminum pieces of weather stripping for the side jambs, floor jambs, and the door's head jamb.

One of the most inexpensive options that will not sacrifice insulation capacity is steel doors that incorporate insulation. This option offers less customization than wood or fiberglass alternatives but can be functional and high performance while providing a smooth, attractive, and durable replacement for your exterior doors.

If having a comfortable home is your priority, there is a growing selection of Passive House doors out there. These exterior doors have multiple seals and locking points and have an R-value of 10 or higher. These doors offer twice the insulation value as a typical door. If you're planning to spend $3,000 to $8,000 on a door, then a Passive House door is worth looking at.

Article by:

Tobias Roberts

Tobias runs an agroecology farm and a natural building collective in the mountains of El Salvador. He specializes in earthen construction methods and uses permaculture design methods to integrate structures into the sustainability of the landscape.