Guide to Effectively Insulate Your Garage

When the days get shorter, and the warm summer air gives way to the first subtle chills of fall air, you can count on two things happening. The once thick trees and flowers are laid bare as the leaves begin to change, and you’ll have to start thinking about winterizing your home.

Although it’s a task that many homeowners dread, it’s a necessary annual chore to prepare for the brisk winter air and freezing temperatures that can be very unforgiving. If you don’t prepare correctly, these conditions are hard on your home and even harder on your wallet.

Even though it’s not on the list of many homeowner’s favorite things-to-do lists, it’s something we must diligently prepare for every year. This chore doesn’t have to be as tedious and time-consuming as we make it out to be.

When you’re ready to descend upon the garage to survey what you’ll need, you should keep in mind that proper insulation and efficient winterizing tactics are of utmost importance. Luckily, we’ve prepared a guide to assist you with this formidable winter opponent that hopefully makes life a little easier heading into the fall and winter.

This garage door is an Eastman E-21 design, 9' x 7' size, Ice White doors and overlays, 8 lite Orion windows.

These single garage doors are in the Eastman E-21 Design, 9’ x 7’, Ice White doors and overlays, 8 lite Orion windows.

Prepare Your Garage Door Beforehand

This garage door is an Eastman E-21 design, 9' x 7' size, Ice White doors and overlays, 8 lite Orion windows.

This garage door is a North Hatley LP Design, 9’ x 7’, Desert Sand, windows with Richmond Inserts.

The Importance of R-Values

When the cold winter air sets in, your garage can be one of the most problematic areas of your home. In some homes, the garage door is constantly opened and closed. The sheer size of the garage door alone can destroy any hopes of keeping the cold air out if insulation isn’t efficient.

The only way we keep this cold air at bay is by ensuring that all the garage components are properly rated as far as insulation standards are concerned. These insulation standards are where R-values come into play.

Good insulation is required to keep the warm air in and the cold air out. The R-value measures how efficient a specific surface is at insulating the area where it’s installed. For example, a ceiling or roof is rated at an R-40, while interior walls are around R-16.

The higher the R-value is, the better that surface is at insulating. Larger areas we rely on to keep cold air out should always have a higher R-value, like garage doors and ceilings.

How much thermal insulation do you need for your garage?

Since the garage door is a large entrance into your home with potential cracks and other spaces that could allow cold air in, having the proper R-value is of utmost importance. These factors are the main elements when considering how well your garage should be insulated:


When a garage is insulated heavier than usual, an R-16 rating is most likely the baseline for insulation. In cases of lower amounts of insulation, a rating of R-12 should suffice.

Attached vs. Detached

Since attached garages have a direct line of access to the main part of your home, they should be insulated much heavier. Detached garages won’t affect the heating ability of your home by letting cold air pass, so you’re fine with lower amounts of insulation here.


If you’ve decided to convert your garage into a living area or high-usage room such as a gym or dining room, an R-16 is recommended.

Insulating materials

There are two main insulation materials used on garage doors:

Polyurethane is a foam that’s injected into the inner panels of your garage door. When the foam is released into the door, it quickly occupies any empty spaces inside the door panels. When the door gets filled with enough of this material, its ability to insulate increases substantially. Extra support and durability are also provided through the use of polyurethane.

Polystyrene is otherwise known as Styrofoam. Garage doors also contain this material internally, although it’s not nearly as strong as its sprayable counterpart. Garage doors also suffer from a durability standpoint because Styrofoam isn’t nearly as strong as polyurethane.

See the difference between polyurethane (on the left) and polystyrene (on the right) insulation for garage doors

See the difference between polyurethane (on the left) and polystyrene (on the right) insulation for garage doors.

Other essential elements you shouldn’t forget…

Bottom garage door gap

Your garage door weatherstripping should be inspected every year and changed when necessary. The bottom of your garage door contains a rubber seal that makes contact with the threshold to keep out cold air and other negative elements.

Garage door opener

Your garage door settings should be adjusted to the appropriate settings to make sure the door closes completely. As a general rule, you should be able to slide your fingers underneath the door, but just barely.

Garage door sides and top

The perimeter of your garage door can be sealed with several types of material. One of the most popular is vinyl weatherstripping. These panels are placed around the sides and top of the garage and match the color and theme of your home while keeping out cold air, dust, debris, and animals.

Are Your Walls Well Insulated?

Walls and ceilings

If you’re unsure about what level of insulation to choose for the walls, you should consult with a professional. Always remember interior and exterior walls should be rated differently, just as the floor and ceiling are rated differently. has a four-step guide to preparing your walls for insulation:

Step 1: Remove everything from your garage walls.

Step 2: Any damage gaps, holes, and cracks should be patched with putty or mud.

Step 3: Place the fiberglass insulation in the necessary areas.

Step 4: Install drywall over the insulation.

Insulate your walls to save energy costs with foam.

Insulate your walls and ceilings adequately, and you will save energy! Image from Pixabay.


Natural lighting is a great idea for your garage, especially if it’s going to be used heavily. However, keep in mind that the windows should also be properly insulated and rated for cold weather. These are some of the most efficient ways you can prepare your windows for winter:


Did you know you could use weatherstrip tape to cover the cracks around the window that let cold air in? Cut strips of tape to fit the length where they’re going to be applied. Lay them down flat and smooth them out to remove any air bubbles.


Window caulking can peel and become brittle after certain lengths of time. Constant exposure to sunlight and cold air can lead to this damage. Stronger types of caulk can be purchased that last longer than normal. Refer to this article to learn which caulk is best for you and how to apply it.

Window treatments

Thermal curtains are installed to help with the efficiency of your windows. These curtains are much thicker and do a great job of keeping cold air out in the winter and blocking the sun during the hotter months.

Note: Your garage windows can also benefit from these tips!

Light switches and outlets

Conservation Mart released a report stating that approximately 2 to 5% of air infiltration comes through your electrical outlets. This is incredibly significant considering the fact that most homeowners ignore their light switches and outlets when winterizing their homes.

There are 7 easy ways to help you insulate your garage switches and reduce heat loss. Follow the tips to add another level of protection to your home this winter.

Reduce Condensation in Your Garage

The garage is a haven for condensation issues. The porous concrete combined with fluctuating temperatures makes it easy for moisture to manifest in the garage area.

Keep the water out from your garage floor

There should be proper drainage on your garage floor to prevent pooling water. A simple drain in the middle of the area is sufficient enough to keep water at bay. When incidents occur that lead to water on the garage floor, use a push-squeegee to move the water towards the drain.

Humidity can also lead to condensation and bacteria. It’s important to prevent condensation from building up due to humidity.

A garage door that keeps rainwater from running in your garage.

This garage has the proper garage door seal, and floor finishes to prevent water from leaking.

Coating your floor can seal it enough to prevent moisture from manifesting through the porous concrete floor. A dehumidifier is almost mandatory in any garage and can help prevent condensation of all types.

Heat your garage to control your home temperature

You can use several types of heating mechanisms to raise the temperature of our garage and control the humidity and condensation. Heated floors, space heaters, and other solutions can help keep moisture at bay.

Do you Still Have Questions Regarding Your Garage Door Insulation?

If you need assistance beyond the tips you just received, we can help!

Have you heard about our garage door maintenance and repair services?

Caspersen Door Systems can come to your house to perform maintenance or a routine check and let you know what needs attention. They can also help you decide on which hardware accessories you need!

Our garage door technicians can also perform your maintenance for you. Why use your precious time when we can handle it for you?

Contact us at 508-563-5633 if you’ve decided to overhaul the garage door completely. We have designs and styles to suit everybody!

Start with our image gallery that displays all of the residential garage doors we offer. We have a wide variety of styles, colors, and surfaces to match the theme of your home. Use our Design Centre to create a custom garage door.

When you’re ready, we can send you a free quote by email so we can move forward with the installation process.

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