Insulating the garage is one of the most important yet most overlooked aspects of insulation. So, if you wish to convert your garage into a functional space, this detailed guide will help you pick the right insulation to effectively get the job done.


4 common types of insulation for garages:


Fiberglass insulation

In case you hadn't heard, fiberglass is the most common type of insulation in the U.S. Since 1938, it's remained a crowd favorite for its ability to brilliantly trap heat, making spaces more comfortable.

Fiberglass insulation is typically used as loose-fill for unfinished walls or to sound-proof your garage for those band practices.

Because fiberglass is literally made of fine fibers of glass, you can also spray it into the remote, inaccessible corners of your garage.


Pros of fiberglass -

  • Fiberglass has a great insulation capacity.
  • It doesn't get wet or absorb water.
  • It's a cheaper insulation option, which is also one of the reasons for its immense popularity in the country.
  • If you have wood or steel-framed walls, you won't have to use a separate fire stop as fiberglass insulation is accepted by most of the United States' building codes.
  • Made from recycled materials, fiberglass insulation is the perfect choice for environment enthusiasts.

Cons of fiberglass -

  • Since it can only be used for insulating your garage's exposed wall cavities, you can't install it in older constructions. If you want fiberglass insulation, it has to be done in a newly built garage.
  • For older constructions, you will be required to remove and install your drywall, which can increase your costs.
  • Fiberglass can induce a bunch of respiratory issues during installation and even irritate the eye. So, it's important to get in touch with a professional to insulate your garage using fiberglass.
  • Because it can leave air pockets behind, fiberglass can significantly increase your electricity bills.

Cellulose insulation

Something for the drywalls.

You can directly install cellulose on drywalls without spending too much from your pocket. It's definitely cheap and easy to install, as well. Made from cardboard and newspapers, they're the best way to recycle paper and convert it into garage insulation.


Pros of cellulose -

  • Cellulose is a go-to choice for people who are conscious about the environment and want to recycle paper as much as possible.
  • Even though it's cheaper than its counterparts, cellulose has a high R-value, making your garage more energy-efficient and less pricey.
  • It offers a decent amount of protection against vermin and insects, so you can have a mold-free garage.
  • Unlike fiberglass, you can use cellulose on finished walls.

Cons of cellulose -

  • Like fiberglass, cellulose, too, will allow air movement. So, it might not be the perfect choice if you're looking forward to high energy savings. You may want to consider opting for spray foam or injection foam insulations.
  • Installing cellulose is a mammoth task because it produces a lot of dust during the process. So, you might have to either buy a certified breathing mask or hire a professional for insulating your garage.
  • Because it's literally recycled paper, cellulose naturally absorbs water and gets wet easily. Also, the chemical used to treat cellulose is extremely harmful to the environment. So, you have to decide what's more important to you - recycling paper or saving the planet from some chemicals.

Injection foam insulation

Used to seal wall cavities, injection foam is known for its. durability and heat-trapping ability. Since it can be applied by drilling holes into the wall, you can use it for insulating your garage without tearing down the drywall.


Pros of injection foam -

  • Injection foam insulation offers excellent heat resistance. As a result, this reduces the number of air leakages and brings down your electricity bills.
  • It's a class-A fire retardant.
  • It has one of the highest R-values, is water repellent and eco-friendly.

Cons of injection foam -

  • It's a friend to molds. Leave the garage locked for a few weeks and you'll see the mold magically appear on the walls and ceilings.
  • Since you might not know how the walls were made, you won't be able to inject foam for insulating your garage. If your walls don't have a stud cavity, there will be no place for the foam to fit in.
  • If you don't have sheathing, you can't use injection foam because it will take a lot of time to set up.
  • You can't use injection foam insulation on walls with existing insulation. You can try filling them but it will hinder the process.

Note: It's not impossible to remove the insulation, but it's certainly a tad time-consuming. But if you still wish to remove your existing insulation, check out this quick guide to help you with the process.


Spray foam insulation

While they have the same properties, spray foam and injection foam aren't the same product. Their application vastly differs from each other. Unlike injection foam, spray foam is applied to open cavities for insulating your garage. To create an air seal and to make your garage more energy efficient, they're applied to the ceiling, as well.


Pros of spray foam -

  • Spray foam insulation has high energy efficiency due to its unparalleled ability to seal the place air-tight.
  • It can cut down your electricity bill by 50% right from the first month.
  • It doesn't absorb any moisture and therefore, keeps your garage dry and mold-free.
  • Spray foam retains its R-value and is incredibly safe for the planet.

Cons of spray foam -

  • If you experience extreme temperatures in your region, your spray foam might shrink.
  • Spray foam may not be able to insulate every inch of your garage. And when that happens, you can be left with water damage.
  • It's costlier than its counterparts and requires a professional insulation contractor to do the job.

Remember, insulating your garage isn't an expense. It's an investment. So, even if it costs you more right now, the long-term benefits outweigh the cost and make it worth it.