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Pros and Cons of Insulating a Garage

A collage of garage with insulation.

There are so many things I would like to do with my garage because let’s be real, I never put my car in there. I have considered turning it into a gym, or a work area for all my projects around the house.

One of the major concerns stopping me is that I do not want to do any of these activities with my garage door open. It gets too hot or too cold in there to keep the door closed all the time.

If you are in the same predicament as me and wonder what are your options, keep reading. This article addresses the topic of insulating a garage and if it is really worth it.

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What is Garage Insulation?

In general, garages do not have any type of insulation in them. Insulation is a material that you put between your walls to help keep your house at a certain temperature.

It can protect your house against extreme cold and hot temperatures. It can also help to decrease the amount of noise you hear.

A home that is insulated well also tends to be more energy-efficient. In most cases, garages are not insulated and they are not airtight because they have many air gaps. You can insulate the walls, ceiling, and garage door with the highest R-value.

The R-value is the number that indicates the amount of resistance the insulation provides against outside temperatures. Since garages have a lot of air gaps, you need to fill those or no amount of insulation is going to help control the temperature in the garage.

You can fill the cracks with low expanding spray foam. You want to check the weatherstripping at the bottom of the door to make sure it is intact.

Once you have checked all of those areas, you must decide which type of insulation you want to use. There are many different options and each one has different perks. The best insulation option for a garage is foam boards. Foam boards are relatively affordable and fairly simple to use.

They are made from polystyrene and come in stiff boards. They are lightweight and durable. They can stand up to the harshest conditions. With a measuring tape, box cutter, and adhesive, you can insulate your garage with these boards.

Another inexpensive option is batt insulation. This is the typical insulation that you see and it is made of fiberglass. It has extremely fine fibers of glass in it, hence the name. This insulation looks fluffy on one side and has a paper backing on the other.

It can come in rolls or precut to fit industry-specific sizes. While this is not the most ideal insulation for an entire garage, it is useful in some places within the garage when used strategically. This type of insulation is used behind walls and above ceilings.

A close look at a wall installed with fiberglass insulation.

There is the insulation that is loose and blown-in between the walls. This type of insulation is made of various different materials. This is an inexpensive option for a small area. The larger the area gets, it can become expensive quickly.

A look at a wooden attic ceiling with foam insulation.

Another type of insulation is an insulating foam sealant. This is a spray foam that comes in a can and can be made from various materials. You can get it in large quantities for big spaces.

A close look at a wall with insulation maintained with foam sealant.

What are Some of its Benefits?

There are quite a number of benefits to insulating a garage. Insulation can help slow down the transference of heat, or cold because it presents a barrier. It does not keep the heat or the cold out, it just slows it down.

However, adding insulation can make the garage feel less cold or hot, depending on what is happening outside. If you want to heat your garage, insulation will help keep the heat in so it feels warmer and you are not throwing away your heat.

When you are able to keep the heat in or out of the garage, it can make your house more energy-efficient. This could help to lower your heating and cooling bills because your HVAC system will not have to work as hard to cool or heat the house.

If you are interested in turning your garage into extra space, such as a gym or a work area for a car, then you probably want better control over the temperature in the space which is a good reason to insulate it.

Many of us use our garage as extra storage and while an uninsulated garage provides protection from the elements, usually, it does not provide protection from extreme temperatures. Insulation can protect your items from humidity and rust, which can destroy them.

Insulation can protect those in your house from carbon monoxide poisoning. Many people start their cars in the garage, which creates this deadly gas and without proper insulation, it can seep into your home.

When you insulate your garage, it can also help provide a sound barrier. It can help keep the sounds from working out or music inside your garage. It can also help to keep out unwanted sounds from outside. It could potentially save your relationship with your neighbors because it will keep your noise in and not bother them.

The cost of insulating your garage will vary depending on the size of the garage and the material you are using. It also depends on how much insulation you use for your garage. A rough estimate for garage installation is $0.50 to $1.25 per square foot.

The average size of a two-car garage is 20 x 22, which is 600 square feet. That means a rough estimate for the average insulation of a garage is between $300 to $750.

What are Some of its Drawbacks?

A look at a garage under construction with insulation installed.

There are many advantages to insulating your garage, but before you run out and get some insulation from your local hardware store, make sure you know everything you need to know. If you are going to insulate your garage, you must also insulate your garage door.

If you do not insulate your garage door, you are wasting your time with everything else. You also must fill in all the cracks and openings everywhere within your garage. While they may seem small, they let a lot of cold and hot air in and out.

If you live in an area where the temperature is warm all of the time, insulating may not be the best idea for you. You bring your hot car into the hot garage on a hot day and all you have done is created more heat by keeping it all in with insulation.

If you have to open your garage door to let the heat out and to cool down your garage, then you do not want to insulate it. If you have to do this and you have insulation, you may want to consider removing it, if you can.

In general, the cost of insulation is fairly low. However, if you are insulating a large space, the price can go up quickly. If you are insulating your garage with the hopes of making the money back with energy bills savings, you may not see that type of return on your investment.

If you do, it will take a number of years before you see it and that may not make it worth it to you. You will see large savings in heating costs if you have a room or usable space above your garage.

In that case, insulation is the way to go. Most of the insulation options available are easy to install and you can do it yourself without any help from a professional.


I do not live in an area where it is hot all the time. I live in an area that has moderate temperatures across the board during the winter and summer. Therefore, insulating a garage makes sense for me. I would like to create a gym in my garage and want to make sure I can maintain the temperature within the garage.

However, that being said, I do not think that insulating a garage is a good idea everywhere across the board. It really depends on why you would like to insulate your garage.

If you are doing it to ultimately save money on your energy bills, insulation may not be the best way for you to spend money. You are most likely not going to recoup your money by insulating your garage.

Overall, insulation is not that expensive and it is simple to do, so for those living in a moderate climate, it can be a good idea just to insulate your garage for general reasons, not just to see cost savings.