Now slide your metal sleeve into the hole. It should fit snugly, like a new pair of jeans. If it’s too tight, trim the hole a bit. Too loose? Use shims (little wedges of wood) to fill gaps. Shims are your best friend—they fix wobbles and make you look skilled.
Secure the sleeve to the studs with screws. Use a level again to make sure it’s perfectly straight. A tilted AC will leak water inside your wall, which is a code for “mold party.” Nobody wants a mold party—it’s not fun, and the guests are tiny and fuzzy.
Seal the seams around the sleeve with foam insulation or caulk. This keeps cold air in and hot air out. Think of it as putting a winter coat on your AC’s new home.
A man is in the process of installing an air conditioner on a wall
