What Is A Good Garage Door R Value? [Comparison Chart]

If you’ve shopped for a new garage door recently, you’ve likely heard the term “R-value” thrown around a lot.

Unless you’ve done a lot of home renovations, you may not be familiar with the term or know why it’s relevant to your garage.  

What is a good R-Value for a garage door? Detached garages need a lower overall R-value (between 0 and R-6). Attached but not actively heated or cooled garages should have a garage door with an R-value between R-6 and R-9. Actively cooled or heated garages should have a garage door with an R-value of R-13 or higher to save on energy costs.

In general, a higher R-value means better insulation, but there’s more to it than that.

Let’s dig in a little further.

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Why Is Insulation Important for Garage Doors?

Besides being literally a giant hole in the side of your house, garage doors are typically made of thin metal materials which allow heat to transfer in and out easily – usually either steel or fiberglass.

Fiberglass doors are lighter and more efficient than steel garage doors, but less durable. While other garage door materials are available, the vast majority of garage doors are made from steel.

Steel doors conduct heat very well. This means that your garage door becomes very hot in summer, and in the winter, it becomes very cold.

That then causes the air inside your garage to change temperature as well.  

The point I’m trying to make is that garage doors are horribly inefficient at regulating the temperature in your garage.

Garage Door R Value: The Basics

So that we’re all on the same page, let me go over some basics about insulation and how it relates to garage door R values. If you want more details, I go into the subject in a lot more depth in my article on garage door insulation.

Insulation is rated on a scale called an R-Value.

When the R-value of a material is low, it conducts heat very easily. When a material’s R-value is high, it does not conduct heat well, making it a good insulator.

The US Dept of Energy considers “High R-Value walls” to be R-40 or above for Zero Energy Ready. Currently, there are no Energy Star rated garage doors.

Let me give you an example.

If you leave an all-metal spoon in a pot of boiling soup, it will gradually heat up to the temperature of the soup. Then, if you grab the spoon, you’re going to burn your hand.

This is because metal conducts heat well and transfers that heat quickly. We would say this has a relatively low R-value.

By contrast, a spoon with a rubber handle (insulation) wouldn’t get as hot, so it would have a comparatively high R-value.

Garage Door R Values: More is Better (to a point)

16 is twice as much as 8, right?

Not if you’re talking about R-Values and their energy efficiency.

Garage door R values follow the law of diminishing returns, as seen from this chart from Amarr garage doors.

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Manufacturers naturally want you to think that an R-16 garage door is twice as effective as an R-8 garage door because that’s how our brains work.

They’ll price their garage door to take advantage of it even though you’re not getting twice the energy savings.

The lesson from this is to be careful when you’re shopping for insulated garage doors.

You might think you’re buying a door that’s twice as efficient when you’re really only getting a slight improvement in energy efficiency.

Recommended R-Values for Garage Doors

Generally speaking, not everyone needs a garage door with a really high R-Value. Choosing a good R value for a garage door depends on what kind of garage you have and how much time you spend in it.

Here is the breakdown of recommended R values: 

• Non-insulated to R-6 insulation: I recommend this range for non-insulated and detached garages where you don’t spend a lot of time working. If the walls of your garage aren’t insulated, then it doesn’t make sense to have an insulated garage door.
• R-6 to R-9 insulation: I recommend this range for attached garages that are not conditioned (heated or cooled, depending on where you live). The doors are reasonably inexpensive but still provide enough insulation to prevent cold damage to any items stored in the garage.
• R-9 to R-13 insulation: This is the recommended range for conditioned (heated or cooled) garages. You want your garage door R value to be as high as possible so the air you’re heating or cooling stays inside where you want it.  
• R-13 insulation and higher: If you’re trying to create a Net Zero home or have converted your garage into a living space, this is where you want to be looking. You’ll pay a premium for these garage doors, but you’ll also save a lot on energy costs over the life of the garage door.  

Beyond these general recommendations, it’s a good idea to get the highest garage door R value possible if you want to be energy efficient. However, the price of a garage door goes up significantly due to the increased cost of materials. 

Additionally, the more insulation you add to your garage door, the higher the weight becomes. Insulated garage doors usually require a higher-horsepower garage door opener than non-insulated doors.

Insulated Garage Doors From Major US Manufacturers

I struggled to make sense of all the different options when I was doing my research, looking for a new insulated garage door for my home.

So to make things easier, I compiled a list of insulated garage doors from some of the major garage door manufacturers in the United States.

That way, I could look at everything all at once and narrow my options down to five or six garage doors instead of thirty. Hopefully, this will make things easier for you too.

Wrapping It Up

In this article, we’ve covered an overview of garage door R values. Investing in an insulated garage door isn’t the only way you can make your garage more comfortable.

Here are two often overlooked ways to fix up your garage: 

• Adding insulation to the walls. This was one of my first big garage projects and has made a huge impact. If you want to see how I did it, check out my series of articles where I insulate my garage walls before adding drywall.   
• Adding insulation to the ceiling. This is a step that many people don’t consider, but the ceiling is one of the most important places other than the garage door to provide insulation, as heat rises and is most easily lost through badly insulated attics. This is especially important if you have an attached garage with living space above it.
• Add a garage door insulation kit: If you don’t want to spring for a whole new insulated garage door, installing a garage door insulation kit from Matador is a cost-effective alternative. You can see how I did it in that step-by-step guide linked here.