How to Install Air Conditioner Foam Board

Lead Image for How to Install Air Conditioner Foam Board
  • 1-2 hours
  • Beginner
  • 25-40
What You'll Need
Drywall Saw
Duct Tape
Insulated Foam Board

A window unit air conditioner can be a lifesaver during a hot summer. However, they are a source of drafts and heat loss in the winter. You will need to either remove the window unit and store it or find a way to insulate the opening from the cold. For this purpose, the insulated foam board is excellent and can be purchased at almost any hardware or home improvement store.

Choosing the Best Foam Board for the Job

When choosing a foam board insulation to insulate the window opening where your air conditioner is installed, you don't need to purchase anything expensive or elaborate. In fact, you should choose the type of foam board insulation that is on sale for the lowest price at the hardware store or your local home improvement center. Although foam board insulation with a higher R-rating will be more effective in keeping out cold air during the winter, the difference is negligible.

In most cases, the foam board will serve to keep out drafts and wind from the outside more than the cold air itself. When you consider this, expensive foam board insulation doesn't do any better job of blocking drafts or wind than does lower R-rated sheets of foam board. That being said, it is it's not a bad idea to purchase foam board insulation that has a foil on one side or the other. This will help to reflect light from the sun during the day and further prevent cold air from entering your home. However, don't pay a premium for this as it doesn't help that much.

Creating a Box Cover for Your Air Conditioner

If you want to protect your window unit air conditioner from the cold and moisture caused by snow, you can also create a foam box made out of foam board insulation. You can use duct tape, caulk, and other adhesives to construct a foam board box that will cover the entire window unit during the winter months. This will not only protect your window unit air conditioner, it will also save you from having to remove the unit from your window and store it.

The design of the box doesn't need to be too elaborate, and you can even use a large cardboard box as the form for your foam board design. You can strengthen the cardboard box by gluing the pieces of foam board insulation to the outside of the box and then using duct tape to secure it to the window opening. In the spring, simply remove the duct tape and throw it away. Then, store the box in a location so that you can use it again the following season.

Sealing the Box and Window Opening

Regardless of the type of foam board insulation, you choose to cover the window opening in your home, sealing it properly is much more important. However, sealing the foam board piece in the window is not difficult at all. To do this, simply cut the foam board insulation so that it fits snugly in the window opening over the face of your air-conditioner. Then, use duct tape to tape along the seams of the foam board to create an airtight seal. Although it is not the most attractive solution, it is very effective. Besides, you can always cover the window unit air conditioner with a curtain.