How To Insulate Garage Door For Summer To Keep Heat Out?

Disclosure: We may get commissions for purchases made through links in this post.

Are you planning to turn your garage into a workshop, but it can easily get to a hundred degrees or more in summer? We checked all the possible ways to solve this, and we have the best answer for you.

Follow the steps below to insulate a windowless garage door for summer:

  1. Measure the inside length and width of the panels on your garage door.
  2. Trim the radiant barrier sheet to match the measurements from the panels on your garage door.
  3. Place double-sided mounting tape near all the edges of the panel.
  4. Mount the radiant barrier on the double-sided mounting tape.
  5. Repeat until you have covered the entire garage door with the radiant barrier.

If your garage door has a window, or if your summers are excessively hot, you would need a slightly different insulation method to keep your garage comfortable. Not to worry, we'll delve into the above and other methods right here for you. Take your pick, depending on your garage door style and climate. Read on!

A two story brick mansion with a garage house with three garage doors, How To Insulate Garage Door For Summer To Keep Heat Out?

How to insulate a garage door for summer?

The exact steps to insulate the garage door against the summer heat depend on several factors. Where you live and whether your garage door has a window can affect the insulation method.

Thus, the succeeding sections are grouped based on the type of summer that you get and whether your garage door has a window or not. That way, you can pick the set of instructions that matches your situation and use them!

White garage door with decorative stone cladding

Although, you are very much welcome to read them for added insight into the process!

Insulating a garage door—window & moderately hot summers

A fiberglass insulation block

The window in a garage door is a pathway for heat to get in because sunlight can get through it freely. Thus, unless we effectively insulate the garage door window, the gains from the rest of the insulation will be minimal.

Materials you will need

  • Reflective silver window film
  • Radiant barrier sheet
  • Clear silicone sealant
  • Double-sided mounting tape
  • Scissors or cardboard cutter
  • Measuring tape
  • Squeegee

For this installation, you'll use radiant barrier sheets on the garage door windows. According to Energy Saver, U.S. Department of Energy's (DOE) consumer resource on saving energy, radiant barriers are effective in reducing summer heat.

The thickness of the double-sided mounting tape used will create an air layer with the radiant barrier. The air will absorb the heat from the outside layer of the garage panel. The radiant barrier will then reflect the heat from the air layer back to it, trapping it there.

Try EZlifego double-sided heavy-duty, removable mounting tape. Check it out on Amazon.

Steps to follow

The steps below are for a windowed garage door that experiences moderate summer heat.

Keep in mind to check the manufacturer’s instructions for the reflective silver window film because some are made to be installed on the outside of your window, while the majority are to be installed inside.

  1. Check your garage door window for any gaps and seal the gaps with clear silicone sealant.
  2. Measure the length and the width of your garage door window. Measure your windows individually and never assume that they have the same size. Trim the reflective silver window film based on these measurements.
  3. Slightly peel one side of the reflective silver window film and position it at the base of your window. Slowly peel the backing while using the squeegee to evenly stick the reflective silver window film, pushing air bubbles out.
  4. Repeat steps two and three to cover the rest of the windows with the reflective silver window film. This will reflect the rays of the sun to minimize the heat coming in through the windows.
  5. Measure the length and width of the garage door panels. Make sure to include the inside of the panel lips or flaps. Similar to the windows, do not assume that all the panels have the same measurements.
  6. Trim the radiant barrier sheets based on the measurements of the panels.
  7. Install the double-sided mounting tape on the inside edges of the garage door. Make sure that four edges create an enclosed perimeter.
  8. Remove the tape backing from the double-sided mounting tape and install the radiant barrier on the mounting tape.
  9. Repeat steps five to eight until you have installed the radiant barrier on all the panels of the garage door.

Insulating a garage door—no window & very hot summers

A white garage door for a two cargo garage

According to Overhead Door, most modern garage doors are made of aluminum or steel. Metals radiate heat fast. This means that your garage door absorbs heat from outside during summer then radiates that heat into your garage.

This is the reason why your garage can be a few degrees higher than the outside temperature.

To insulate the windowless garage door of a house that experiences very hot summers, we need to consider the material that your garage door is made from.

Materials you will need

  • Water-based degreaser
  • Etch primer
  • Radiant barrier sheet
  • Coarse plastic brush
  • 2- to 4-inch latex paintbrush
  • Painter’s pot
  • Thermal insulating paint
  • Double-sided mounting tape
  • Scissors or cardboard cutter
  • Measuring tape

Try 13-fl oz package of U-Pol Etch Primer. Check it out on Amazon.

Steps to follow

Follow the steps below to insulate a garage door without windows:

  1. Sand off any previous paint on your garage door.
  2. Apply an even layer of the water-based degreaser on the outer side of the garage door.
  3. Rub the surface with a coarse brush.
  4. Rinse the garage door thoroughly with water (ideally from a water hose).
  5. Wait until the garage doors are completely dry.
  6. Apply an even layer of the etching primer on the exterior of your garage doors. Let it cure for 5-6 hours.
  7. Apply an even layer of thermal insulating paint on the exterior of your garage door. It is best if you choose a light color because light colors help reflect the sun’s heat.
  8. Let the thermal insulating paint dry thoroughly overnight.
  9. Apply a second layer of thermal insulating paint on the exterior of your garage door.
  10. Measure the length and the width of the garage door panels, including the inside of the lips or flaps. Never assume that the panels have the same sizes.
  11. Trim the radiant barrier sheets based on the measurements of the panels.
  12. Install the double-sided mounting tape on the inside edges of the garage door. The four edges should create an enclosed perimeter.
  13. Remove the tape backing from the double-sided mounting tape and install the radiant barrier on the mounting tape.
  14. Repeat steps 10 to 13 to install the radiant barrier on all the panels of the garage door.

Insulating a garage door—window & very hot summers

To insulate a windowed garage door that experiences very hot summer months, we will combine most of the steps from all the previous cases. Having a window on the garage door makes it harder to insulate—but not impossible.

Materials you will need

  • Water-based degreaser
  • Etch primer
  • Radiant barrier sheet
  • Coarse plastic brush
  • 2- to 4-inch latex paintbrush
  • Painter’s pot
  • Thermal insulating paint
  • Reflective silver window film
  • Double-sided mounting tape
  • Scissors or cardboard cutter
  • Measuring tape
  • Polyethylene tape
  • Squeegee
  • Clear silicone sealant

Steps to follow

  1. Check along the edges of your garage door window and look for any gaps. Seal them with clear silicone sealant.
  2. Measure the length and the width of the garage door windows individually.
  3. Trim the reflective silver window film. Check the manufacturer’s instructions to find out whether the reflective silver window film should be installed outside or inside the window.
  4. Slightly peel one side of the reflective silver window film and carefully position it at the window base. Peel the backing slowly while slowly pushing the film on the window using the squeegee to push out any air bubbles.
  5. Repeat steps two to five until you have covered all the windows with the reflective silver window film.
  6. Sand off any old paint from your garage door.
  7. Apply the water-based degreaser evenly on the outer side of the garage door.
  8. Rub the garage door surface with a coarse brush.
  9. Rinse the garage door thoroughly with water from your garden hose.
  10. Leave the garage doors to dry naturally.
  11. Apply the etch primer evenly on the exterior of the garage doors. Leave it to cure for 5-6 hours.
  12. Use the paintbrush to apply an even layer of thermal insulating paint on the garage door. Light-colored paints help reflect more of the sun’s rays and heat.
  13. Let the paint dry overnight.
  14. Apply an even second layer of the thermal insulating paint.
  15. Measure the length and width of the panels starting from under the interior flap or lip.
  16. Trim the radiant barrier using scissors or a cardboard cutter.
  17. Install the double-sided mounting tape on the inner edge of the panels. Create an enclosed perimeter with double-sided mounting tape.
  18. Remove the tape backing and attach the radiant barrier to the mounting tape.
  19. Repeat steps 15 to 18 until you have installed the radiant barrier on all the garage door panels.
  20. Measure the length and width of the windows.
  21. Trim the radiant barrier based on these measurements.
  22. Position the radiant barrier to cover the windows. Use the polyethylene tape to keep the radiant barrier in place.

After the installation

A single car garage door

Even though the insulation materials that we used are light, it is still important to check your garage door. Your garage door should stay in place no matter which level you raise it.

If it doesn’t stay in place, then you need to adjust the garage door springs.

Conclusion

Insulating the garage door against the summer heat is necessary to make the garage more hospitable during the hot summer months.

Check the following articles that you might find interesting.

How To Insulate A Tent For Winter And Summer Conditions?

How To Insulate Very Large Windows [For Summer And Winter]?

Leave a Reply