garage door R-factor

Do You Need An Insulated Or Non-Insulated Garage Door?

When trying to select a garage door often the question is often asked if it is worth the extra money to purchase insulation. Here are a few things to consider & what is the low-down on what insulation is & isn’t.


What R-Value Is & Isn’tgarage door R-factor

R-Value: “the capacity of an insulating material to resist heat flow. The higher the R-value, the greater the insulating power.”

This is a theoretical number used in many industries but it’s a good reference & the best we have. Used alone it wont take into account other real world factors (engineers have other esoteric terminologies for those).

Take for instance a hot steel roof or garage door in the sun. The insulation behind it will perform different that if the steel was replaced with wood. This is thermal conductance or K-value, your steel garage door will transfer heat more cold faster than wood will.

That’s why in some cases even a minimal amount of insulation will act as a thermal break. If an un-insulated garage door is in the sun a good part of the day in the summer this will transfer a significant amount of heat to the inside. This will make for a very hot garage!

You never can lose with insulation IF it is what you need & if so usually the more the better. But that isn’t always the case.


Sometimes It May Not Be Worth The Expense

  • If your constantly opening & closing your garage door the extra money you spent on premium insulation is going out the door.
  • You rarely use the garage for anything other than storage or parking your car. Part of the reasoning for insulating is for climate control for people or animals.
  • Your garage isn’t insulated. Why insulate a garage door if the garage isn’t insulated.
  • The garage is on a rental unit.


Added Benefits To An Insulated Garage Door

  • The insulation will fill the voids on the inside of the door. Garages tend to attract dirt & spider webs even if it’s always closed. If you like to keep your space neat & clean this may be another reason to insulate.
  • An insulated door will be quieter when a garage door opener is used. An un-insulated garage door will rattle & vibrate like a drum. For example if you purchased a garage door opener with a belt drive because you have a bedroom next to the garage.
  • Extra strength. If you have a polyurethane insulated garage door it will be very strong. If you have kids throwing basketballs at the door this is what you want.
  • May help keep the living spaces next to a garage warmer or cooler. Especially if their is no or little insulation in between the spaces.


Different Choices In Insulation

Polyurethane (R-18.4 & R-12.9)intellicore

This has the highest R-Value. R-18.4 is about the R-value of a 2×6 fiberglass bat. It is also the most expensive but makes for a very strong door. It comes only in 3 layer doors (steel on the inside & out). Clopay Door calls this Intellicore. See my post on intellicore polyurethane insulation.

Polystyrene (R-9, R-6.3, R-4.4)

This is the least expensive & comes on two & three layer doors. It is vinyl backed on the inside for added protection on two layer doors.


Insulating An Un-Insulated Garage Door

Some garage door manufacturers sell kits to insulate your garage door. If you have a Clopay door call me & I can install it for my cost of materials plus a service call. Lowe’s & Home Depot also sell kits but they aren’t cut to size so they will look less than ideal. If you are good with a knife & tape I have seen some jobs look good though.


If you have any questions, as always, feel free to call me or post a question below. I will answer all question, even those of you repairing your door yourself.

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