How to Apply Air Conditioner Foam to Improve Efficiency and Performance

Eliminating air leaks in your home can reduce the amount of time your air conditioner runs to eliminate heat and humidity. It can also improve energy efficiency and performance.

This easy-to-install foam seals gaps between your window air conditioning unit and the window frame, minimizing outside air intrusion and noise. It also keeps dust, pollen and insects out of your home.

Weather Seal

Many home improvement stores sell foam seal that can be used to insulate the area around a window air conditioner. This type of seal is also sometimes known as AC weather seal or insulating tape and comes in a roll with a peel-and-stick backing.

Before using this kind of seal, you should clean the area and remove any dirt or grease. This will help the adhesive stick more securely. If necessary, you can frame the area with boards or use a pre-made frame that fits the dimensions of your window air conditioner.

To apply the tape, first measure along the inner right and left sides of the sill (between the bottom of the open window and the sill) and cut a piece of seal to match. Then, peel off the paper backing and position the first length of seal firmly over the gap. Press the rest of the tape into place, working from one side to the other to create a straight and bump-free seal.

Foam Strips

If your window air conditioner comes with a foam strip, simply cut it to size and place it around the unit. If it doesn’t, you can purchase a foam insulating strip at most hardware stores. If the air conditioner is installed in a sliding window, you can also add a fabric cover to help it stay securely in place.

Foam tapes are used for a wide range of applications, including sealing gaps and bonds surfaces to prevent the escape of air or moisture. They feature a quick stick adhesive and come in a variety of thicknesses, carriers, sizes and cell structures to suit many projects.

Neoprene EPDM foam tape, for example, is ideal for weatherstripping and can resist different temperature expansion rates. It has good shock absorption protection and resistance to abrasions and solvents. Other foam tapes may feature a rubber- or acrylic-based adhesive and are suitable for indoor and outdoor use. Some types are available with primers for difficult to bond surfaces like polypropylene and concrete.

Fabric Covers

An air conditioner cover offers a quick and easy way to protect your unit from weather damage. These covers are typically made from breathable and porous fabric that allows for ventilation to avoid moisture buildup. They also help minimize drafts and prevent pests from entering your unit.

Many homeowners use a central air conditioner cover to protect the system during fall and winter. As trees shed their leaves and twigs, winds carry them to your outdoor unit where they can clog it up. These organic materials can interfere with your HVAC system’s functionality once the weather turns warm again.

A cover is not a permanent solution. It can still allow mold and mildew to grow inside the covered area. It’s best to consult your AC manufacturer’s recommendations before covering the unit during the winter. They may provide guidelines that ensure you don’t void warranties or cause any unintended damage to the equipment. Also, look for a cover that isn’t too gaudy or overly expensive.

Other Options

Many home improvement and hardware stores sell foam panels that are designed to fit over the top or sides of wall air conditioners. These are usually easier to install and provide better insulation than the foam strips that you can use on window units.

If you have a wall unit at a height that’s difficult to reach, consider insulating the outside of the unit with a fabric cover. These covers are available at most hardware and home improvement stores and keep out rain, snow and debris.

Another way to improve the insulation around your AC is to create a frame. You can use pre-made frames or build a frame using wood boards. If your air conditioner pad is settling, polyurethane concrete foam can be injected under the pad to lift it up and fill in any cracks.