How Can I Insulate My Window A/C Properly?

When your window air-conditioning system is running, you don't want to leak the cool air outside.

A window air conditioning unit that is not properly insulated can cause your energy bills to increase.A window air conditioning unit that is not properly insulated can cause your energy bills to increase.
Leaking air will increase your energy bills and make your home less cool than you want. During the wintertime, when you are heating your home, a leaky window air-conditioning system will allow heat to seep outside, increasing your heating bills.

Measure the outside portion of your air conditioning unit.

Choose an insulated air-conditioning cover sized appropriately for your air-conditioning unit. Search for a thick variety that contains insulation, rather than a thin, simple cloth cover. Look for this at your local hardware store.

Cut a piece of rigid foam insulation to the size of the area between the side of the air conditioning unit and the edge of the window. Use a utility knife.

Window air-conditioning units typically have an accordion-style adjuster that often fails to keep hot

in or cold air out.

Fit the foam insulation in the area between the window frame and the side of the air conditioning unit.

Tape the foam in place using aluminum insulation tape. You can find this tape at your local hardware store.

Press a foam insulation strip between the window frame and air-conditioning unit, starting in the corner.

Cut the end of the strip off and discard the excess.

Push the strip in place, using the rounded end of a butter knife.

Things You Will Need

  • Measuring tape
  • Utility knife
  • Rigid foam insulation
  • Aluminum insulation tape
  • Butter knife

About the Author

Kennedi Rose is an Atlanta-based journalist who began her career in 2005 as a newspaper reporter covering the education beat. She has written for a wide variety of commercial, trade and online magazines covering food, drink and the retail sector. She holds a Bachelor of Arts in sociology.