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garage that was insulated cheap

How to Insulate a Garage Door Cheap (Step-by-Step)

It’s no secret that insulation can help keep your home warm in the winter and cool in the summer. But what you may not know is that you can insulate your garage door to get the same benefits! Not only will this save you money on your energy bills, but it’s a DIY project that is easy to do and doesn’t cost very much. In this blog post, we will tell you how to install garage door insulation cheap and what the cost is for a typical garage door insulation kit.

Regular, uninsulated metal doors don’t do a very good job of regulating temperatures in your garage. And unfortunately, buying an insulated garage door may not be an option for you financially at well over $1000 (maybe a lot more) these days! Assuming you don’t want to spend that kind of money, keep reading to find out how you can achieve this same goal, but for a much lower cost.

How to Insulate a Garage Door Cheap

Insulating a garage door on the cheap is something almost anyone can do. It doesn't take a ton of time, money, or skill. You just need to be able to use a tape measure and follow 4 easy steps!


Tape Measure
Straight Edge
Sharp Utility or Serrated Knife


Rigid Foam Board Insulation
Foil Duct Tape

Step 1: Measure Garage Door Panels

Measure the panels in your door, making sure to account for the space at the top and bottom that will likely sit within the tracks that will hold it in place. The panels could vary in size from one to another, so make sure to measure and write them all down so you get the correct size.

measure garage door panels for insulation

Foam board typically comes in 4ft x 8ft sheets, so you can add up your measurements to determine how many sheets you’ll need in total to complete the job.

Step 2: Pick an Insulation Material

Go out and purchase foam insulation that fits your door’s needs. More on this below (see Garage Insulation Types), but there are two types of insulation available that we recommend for garage doors.

  • Thick rigid foam insulation – lower cost option
  • Garage door insulation kits – prepared panel kits for insulating 1 or 2-car garage doors

2 types of garage door insulation - rigid foam and garage door insulation kit

When deciding which type to pick, there are three basic things to consider. The first is the R-value, or how well it insulates the door (the higher the number, the better). Next is the price. Buying sheets of rigid foam is usually cheaper than buying a kit. However, the third thing to consider is the amount of your time that could be saved by using a garage door insulation kit.

To recap, you’ll need to weigh R-value and convenience with your budget.

Step 3: Cut the Insulation to Fit Your Garage Door

You know the old adage, measure twice and cut once. Make sure you take into account the space behind the track at the top and bottom of each panel before you cut.

DIY cutting garage door insulation to fit

Once you’ve marked your dimensions using a tape measure, we recommend using a straight edge to cut against so you get nice, straight lines. We find that a serrated knife, even a bread knife out of the kitchen, does best with many of the rigid foam insulations.

To recap, you’ll need to weigh R-value and convenience with your budget.

Step 4: Install the Garage Door Insulation

Once you cut out the first panel, dry-fit it into the garage door section. This will tell you how well you measured the area and if you need to add or remove a bit that hides behind the track. You want the tightest fit possible to get the best results. Once you’re happy with the first panel, the rest should be a breeze.

We do recommend cutting then installing each of the garage door insulation panels one at a time to ensure you’re happy with fitment before moving on. You don’t want to find out later that you cut them all incorrectly, especially if that turns out to be too small.

installing cheap garage door insulation panels

If you’re using the rigid foam, it’s easiest to place the foam in the top track pushing up, then bend it slightly to press the bottom in. Once in place, you can adjust it to where it fits best. Continue through until you have all the panels in place.

Step 5: Tape the Insulation Panels Off

Depending on how tight your insulation panels fit inside the track, you may not need this step. That being said, if it isn’t snug, you’ll want to start taping it to properly seal the insulating material and prevent the cold air from coming inside the garage during the winter. Repeat this process around the garage doors and on each of the panels for best results.

What is the Best Garage Door Insulation Type?

As we mentioned above, there are a few different materials that can be used to insulate a garage door. The main ones include a thick, rigid EPS (expanded polystyrene, reflective foam core, or batting.

best garage door insulation types: polystyrene, reflective foam core, and fiberglass batt

Polystyrene Rigid Foam

Rigid polystyrene is the material we recommend for insulating your door. It has a great R-value (roughly 4 to 5 per inch on average) for the price. It’s also easy to install and can be picked up at your local big-box hardware store. Most commonly, you’ll find 4ft x 8ft sheets and all sorts of thicknesses. One-inch usually works well for garage doors, but a different size may fit your door better. You’ll just have to measure the depth of the track around each panel to determine what it will support. The large sheets come foil-faced and are fire-rated, which is nice.

We think it’s important to note that you can also find this type of insulation in project-type kits. These are marketed as “garage door insulation kits” and you can find them in either 1 or 2-car garage door sizes. The packaged kits are nice because they provide the right amount of insulated material (cut in panels) for your project. You’ll just need to buy the correct kit, depending on if you have a single or double-car garage. You trim as needed and install it on your door just the same way as mentioned above.

Reflective Foam Core

This material is much thinner, usually 1/8″ – 1/4″ when used for garage door insulate, but is marketed with what amounts to a very high R-value, roughly 8 per inch). How is that possible you ask? Good question. It appears that they are taking credit for the R-value in the air gap that is created between the door and the reflective foam core. So, while it presents itself as a great insulation to cost value, it may not be what it appears. This foam core material is much thinner, yet more flexible than the rigid foam, and the cost to cover an entire garage door is about the same.

Fiberglass Batting

Another option for insulation is fiberglass batting. It’s thicker and much more flexible than the two options previously mentioned. It does have a great R-value (as much as 8 per inch or more) and it’s easy to install because of its flexibility, the biggest difference between it and the rigid foam. This is another decent option for an insulated door panel, and there is a kit available from Owens Corning.

What Does an Insulated Garage Door Look Like?

The uninsulated panels you have on your door now are just thin metal and they allow much of the heat and/or cold weather to radiate through and access your garage. Once you replace that empty area with an insulated panel, you almost immediately cut off the cold and heat, taking back your territory once and for all. Here’s an image that shows the difference between an uninsulated panel and one that’s insulated. As you can see, the insulated panels look better AND seal off the weather!

shows what an insulated garage door looks like

Pros and Cons of an Insulated Garage Door

Still trying to figure out if it’s worth the 2-3 hour DIY project? If one of the following is true, it’s a no-brainer: Either you live in a cold or hot climate and you see extreme temperatures one way or the other or you spend a great deal of time in your garage during the summer or winter months.

Here’s a pros and cons list to help you determine if it’s worth the money for you:

The Pros 

Cooler in Summer / Warmer in Winter

Quieter (doubles as soundproofing)

Reduced energy costs

Project quickly pays for itself

The Cons

Costs Money

Install takes a couple hours