Most window
air conditioners have an expanding curtain on either side to help seal any gaps
between the window frame and the air conditioner, but sometimes this seal isn’t
perfect. Even extremely small gaps can leak air, which reduces the efficiency
of your air conditioner and may let bugs and dust into your home. There are
several ways to seal these gaps, but the simplest method is to use
adhesive-backed open-cell foam weather-stripping to fill the space and prevent
air leakage. Smaller gaps can also be filled with a claylike material called
rope caulk.
Gaps Larger
than 1/8 Inch
- Clean the
surface of the window and air conditioner around the gaps. Remove dirt, grease
and dust to ensure proper adhesion of the weather-stripping.
- Measure the
length of the first gap. Cut a piece of adhesive-backed foam weather-stripping
to this length.
- Peel the
paper backing off the cut strip of weather-stripping and position the seal,
sticky side up, along the underside of the window frame.
- Press the
strip along the window frame to get a smooth, tight seal. Do not adhere the weather-stripping
so that it rests in front of the gap. This will not seal it properly. The foam
must be within the gap so that it expands to give an airtight seal.
Narrow or
Hard-To-Reach Gaps
- Measure the
length of gaps that are 1/8 inch thick or smaller. Tear off a length of rope
caulk to match. Rope caulk is similar to putty or modeling clay but is
removable at the end of the cooling season when you remove your air
conditioner.
- Press the
caulk into the gap. If the gap is deep, you may need to press two pieces into
the gap to fill it completely.
- Smooth the
caulk and wipe away excess from the window frame and air conditioner with a dry
cloth.
Things You
Will Need:
Tape measure
Adhesive-backed
foam weather-stripping
Utility
knife
Rope caulk
Cloth
Tip:
Gaps larger
than 1 inch should be filled with fiberglass insulation stuffed into the gap
tightly.
In most
types of windows, gaps are commonly found along the top, where the window meets
the air conditioners, at the corners and along the bottom at the sill.
If the rope
caulk is still clean and flexible when you remove your air conditioner, peel it
off the window and store it in a sealed plastic bag for later use.