Garage Insulation: The Surprising Energy Saver

At an average size of 400 square feet, garages are an important part of our properties. Not only do they shelter our vehicles from extremes of weather and would-be thieves, they also usually multi-task. The typical American garage may serve as a workshop, craft room, man cave, music practice studio (ever wondered where the term “garage band” originated?), or private storage unit. The only problem with this is that throughout much of the country, garages tend to be freezing in winter and broiling in summer. Although many people never think of adding insulation to their garage, it can be an excellent energy-wise move.

Advantages of Insulating Your Garage: For You

To put it simply: when your garage is insulated, you’ll tend to be more comfortable working or playing in there, no matter what the season. In addition, if your garage is attached to your home, you will be preventing the loss of heat or air conditioning from the rest of your living space as well. And if you are the proud owner of a FROG (furnished room over the garage), insulation will help make the HVAC in that area perform better too. The end result is greater comfort for you and your family together with lowered utility bills.

Advantages of Insulating Your Garage: For Your Belongings

Now it could be that you’re in the minuscule percentage of homeowners or renters who never utilize their garage for anything except parking the car and storing household possessions. Even this type of usage can benefit from insulation, though. Either frigid or sultry air can be rough on your vehicle; a dead battery may result in either case. Ditto for sensitive objects that you have stashed in the garage. Extremely high temperatures will damage such things as canned goods, wine, and medication. Other stored items like house paint and electronic equipment can be equally affected by heat or cold.

Insulating Threshold and Walls

If you’d like the quickest fix available to help insulate your garage, try one of the kits for weather stripping the garage door threshold. These are easy to apply and will help keep out drafts, rain, or snow, and even fallen leaves or other debris. If they were not already insulated by the original builder, you can also apply insulation to the walls and ceiling of your garage, plus the access door leading into your home as a DIY project. The most eco-friendly material you could use here is zero-waste shredded recycled denim insulation, which is a more expensive but safer substitute for conventional substances like fiberglass or mineral wool insulating batts or spray polyurethane foam.

Insulating the Garage Door

One caveat: Although you may hear about using readymade kits to insulate garage doors — or applying foam board as an even cheaper alternative — be cautious. Your garage entrance is quite different from any other type of door in your home. It is controlled by torsion springs under high tension, which are precisely adjusted for the door’s existing weight. The addition of insulation and its extra poundage can cause a dangerous imbalance. For safety’s sake, consult a professional regarding insulating your garage door. Of course, when you are in the market for a replacement (garage doors have an average lifespan of about 30 years), it’s worthwhile to look for an energy efficient, pre-insulated door.

Laura Firszt writes for



Jan K
Jan S4 months ago

Thank you

Jessica P
Jessica Palmer6 months ago

I apologize for the bump...
I've been battling heat in my shop since I moved into my current home eight years ago. I live in SoCal, and my garage door faces west. The afternoon sun has always heated up the shop to levels that make me spend less time in the shop.

I added a mini-split HVAC, and that helped enormously. But in the summer, when the outdoor temps can get over 90 degrees (sometimes over 100), and the afternoon sun is beating on the garage door, my mini-split had no hope of keeping up, and shop temps would climb.

I insulated the walls and ceiling, and that definitely helped. But my mini-split was still no match for the summer afternoon heat.

So, I got a thermal imaging camera. I learned a few important things that have helped get the heat under control.

First, the uninsulated steel garage doors were acting as a giant radiator. I knew that, but I didn't realize just how much that contributed to the problem. On those 90 degree days with the sun beating on the door, the temp of the outside of the garage doors would get over 120 degrees. The inside of the doors would get over 110. Since my shop is a 3-car garage, that's a lot of heat! No wonder the inside of the shop kept getting so warm.

I bought those garage door insulation kits from a big box store like this

(I think HD). That made a significant difference, but the doors were still a big radiator. Instead

Siyus Copetallus
Siyus Copetallus3 years ago

Thank you for sharing.

Jan Hill
Dr. Jan Hill3 years ago


Miriam O.

Thanks so much for sharing this with us!

Jonathan Harper
Jonathan Harper3 years ago


Jim Ven
Jim Ven3 years ago

thanks for the article.

Dave C.
David C3 years ago


Fi T.
Past Member 3 years ago

Make effective use of our natural resources