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The Truth About R-Values


When you hear the term R-Value does it make your head hurt? If you take-on any form of DIY home improvement you have probably run across this term on more than one occasion. We at Delden believe an informed customer is the best customer. In this blog we will break down what R-Values are and how they pertain to the largest door in your home.

First let’s start by defining what the term R-Value means.

“R-Value is a measure of thermal resistance used in the building and construction industry. Specifically, R-value is thermal resistance to heat flow. Many manufacturers use R-values to show the energy efficiency of their product. This number is calculated based on the thickness of the insulation and its chemical properties. The higher the R-value number, the better the insulating properties of the material. However, an R-16 value is not twice as good as an R-8 Value. R-16 does not offer twice as much thermal resistance or twice the energy savings of an R-8 value. A value of R-16 offers a 5% reduction in heat flow and a 5% improvement in energy efficiency from a value of R-8, not 50%. See chart below for R-Value comparisons.”

This definition and more information about energy efficiency and your garage door can be found on our website under the Before You Buy tab. Click here to read more.

When it comes to R-Value and your garage door there are a few things to take into consideration before jumping into a high R-Value rated door.

Determine the daily usage of your garage door such as
-Is it used for your vehicle and opened several times a day
-Is it a workshop, living space or storage area and rarely opened
-Is it a mixed use space
-Is the garage insulated
-Is it a temperature controlled environment with a heating and/or cooling vent

Where is your garage door located?
-Is it below part of your living space
-Is it attached to your house

Once you know how the space is primarily used then you can decide on the R-Value that suits your needs. If your garage door opens several times a day then a high R-Value can be overkill. The slightly warmer air in the garage will escape every time the door is opened.

If your garage is a workshop area or you heat your garage but only open it in the summer then a slightly higher R-Value may be appropriate. To get a better understanding of R-Value and the percentage of improvement in energy efficiency please see the below graphic.

There is some concern when it comes to garage door dealers wanting to sell you high R-Value doors. On Martin Holladay’s blog, Musings of an Energy Nerd – Energy-Efficient Garage Doors found on, he discusses the unimportance of high R-values in garage doors and windows.

“The R-values that are trumpeted by garage-door manufacturers are measured at the center of one of the door panels,” stated Holladay. “No manufacturer, as far as I can determine, reports the R-value of the entire door assembly (including the panel edges, the seams between panels, and the perimeter of the door) in their promotional materials. Moreover, manufacturers’ reported R-values tell us nothing about air leakage. Most garage-door manufacturers are reluctant to share actual laboratory reports showing the results of R-value testing. When I asked…a technical representative for [a major garage door manufacturer], if I could see a copy of [their] test results, he suggested I send him an e-mail. He later e-mailed his response: “I apologize if I misled you. I was informed that this is proprietary information that will not be disclosed.””

At Delden we want you to get the best and most you can out of your garage door. We do not want you to stress over a high R-Value door if it is unnecessary. We do offer garage doors ranging from R-Values of 6.48 to 19.40. If you have questions or concerns about what type of insulated garage door is best for your home, please leave us a comment on this blog and we will be happy to get back with you.


8 thoughts on “The Truth About R-Values

    1. Hi Jordan! Yes it is important and such a complicated subject. You are welcome! Thank you for taking the time to comment!

  1. Your garage door and garage door operators need to be checked regularly to ensure that they continue to operate safely and efficiently. Regular maintenance can save you the cost of an unexpected repair, extend the lifetime of your door, and give you peace of mind.

  2. I live in the Chicago area(cold winters and warm summers) and am in need of a new garage door (and opener) foran attached garage.
    it is a 2 car garage door and is frequently use as our main entry and egress.
    what should i consider as my R-Value and construction for durablity

  3. My wife and I are concerned because we are building a new home in N Carolina.
    Garage sq ft = 696’. In addition to garaging 2 cars, we will use the space for woodworking and art projects all year round, so insulation is important. BUT—the particular style and brand of door design that we prefer is a 6.48 R-value, 4-ply, using polystyrene instead of polyurethane insulation.
    Will that low R-value really be inefficient for heating & cooling insulating? Or does it really matter?

  4. Live in nyc I have a one car garage metal door no insulation garage have no heat and there is living space above please advise which insulation I should buy
    Thank u

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