How To Find The Most Energy Efficient Doors

There Are Multiple Factors At Work, When It Comes To Your Doors And Energy Efficiency

Energy efficiency is a major factor when it comes to entry doors these days, as well as most features in your home. The point of energy efficiency is to help you to have a comfortable, efficient home while using as little energy as possible. When it comes to electric appliances, this means saving money on your electric bills. When it comes to things like windows and doors, however, you’ll be able to save money on your heating and cooling bills.

There’s no question that an energy efficient door can be a boon for your home. But what makes an entry door energy efficient? There are certain criteria you have to look for when seeking an energy efficient door. In today’s blog, let’s break down what that is so you can find the perfect energy efficient door for your home.


The energy efficiency of an entry door is measured by its R-value. R-value determines how well a barrier in your home — such as a window, wall, or door — resists heat loss or, rather, reflects energy. It’s ranked on a scale of 1 to 9. The higher the number, the better it reflects energy, and thus the more energy efficient it is. Most home exterior experts hold that a door with an R-value lower than 5 is inefficient. An ideal R-value is somewhere between 7 and 9. Some R-values of common door materials on average include:

  • Wood Entry Door – R-2 or R-3
  • Fiberglass Entry Door – R-7 or R-8
  • Steel Entry Door – R-5 or R-6
  • Sliding Glass Entry Door – R-2

R-Value can also be impacted by whether or not there’s a window built into the door, and the size of that window. Glass has a lower R-value than standard entry door materials, so the less of a window there is, the higher the R-value, although a window can help with energy efficiency in that it can let natural light into the space. We’ll get into the pros and cons of glass for doors later.


U-value is the rate at which heat transfers through a barrier. In the case of U-value, you want to find a lower U-value for an energy efficient door. U-value is measured between .001 and 3, because less than .001 cannot be measured. Part L building regulations states that standard entry doors should have a U-value no higher than 1.8. Anything more than that allows for far too much heat loss in your home. U-values on average for the common door materials include:

  • Wood Entry Door – .64
  • Fiberglass Entry Door – .34
  • Steel Entry Door – 1.2

Sliding glass entry doors conduct more heat than any other material, which means that they have by far the highest R-value. However, glass doors with low-e coatings offer a somewhat stronger U-value than a standard sliding glass patio door.

Doors With Glass

Again, glass is less energy efficient in terms of R-value and U-value, so it stands to reason that a door with a window included would be less energy efficient than a door without. However, you also have to take into account the amount of light that energy efficient products allow into your home. If your door has a window, that could light your entryway without the use of electrical lighting, at least in the daytime.

There are a few options here to get the best of both worlds. The first is that you could insert thick glass or double-paned glass, generally with argon gas in between panes of glass. Argon gas is non-toxic and odorless, but serves to slow the flow of air between glass, thus lowering the U-value. You can also opt for glass with low-e coatings. Low-e, or low emission, coatings help to let light in while blocking the harmful UV rays from the sun. However, this will limit the amount of light your windows let into your home. In some cases, solar low-e coatings have been engineered in order to get the best result.

Storm Doors

Another way to add energy efficiency to your door is with a storm door. A storm door can be made from wood, fiberglass, aluminum, or vinyl, though it typically has large glass panes. The point of a storm door is to add an extra layer of protection for your door. In an area with heavy storms, a storm door will protect your door from any impact damage. But even in an area where storms are not especially prevalent, storm doors can help to raise your R-value and lower your U-value, making your door more energy efficient.


It’s not an exaggeration to say that the best door materials are only as good as the installation team. If your door is unevenly installed, you will certainly have air leakage and heat loss in your home, as well as if the door is damaged. A well-installed door will fit perfectly within the door frame and optimize your R-value and U-value. That’s why even if you choose to go with a fiberglass door and install a storm door to protect it, you need the right installation crew, well-acquainted with the installation of fiberglass doors as well as your climate. In Orange County, that door company is Today’s Entry Doors.

We’ve been in business for over 30 years, offering the best in energy efficient entry doors. We have a wide selection and we can help you find the perfect entry door for your home. Ready to boost your energy efficiency through your entry door? Contact Today’s Entry Doors today for more information or to get started with a free estimate.

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