Whenever you are choosing an AC unit for your home, the first thing you need to consider is how much cooling the machine will provide. Cooling power for air conditioners is expressed in BTU—British thermal units. The higher the BTUs, the more cooling power the machine has.

To help you calculate what might work best for your space, many air conditioners also offer a square footage estimate. You can shop for window AC units for small rooms, window AC units for 400+ square foot spaces and everything in between.

It’s important to keep in mind that the square footage estimate is based on a room being sealable via doors and air-tight windows and having an average ceiling height. High ceilings and airflow from other spaces can make it much more challenging to cool and area. In fact, a combination of evaporative coolers and fans often works more efficiently in particularly open spaces.

Finally, consider features you might want in an AC unit. You can find window AC units with heat capabilities that make them useful in winter. You might even enjoy controlling your AC remotely when you choose an app-compatible window AC.

Most window air conditioner units are easy to install. Unlike in-wall air conditioners, window units don’t require any cutting through drywall, and you can remove them in winter and store them out of the way. Set yourself up for success by ensuring that you buy a window AC with a cord long enough to reach from your window to the nearest power outlet.

The size of the AC will be a very important factor when it comes to ensuring your window AC fits properly. Keep in mind that not all window styles can accommodate an air conditioner, and some narrow windows may only fit a small window air conditioner. If the windows in your home are not compatible with a window AC, you may find a portable air conditioner to be a good alternative.

While many window air conditioners take up a lot of your window space, some units straddle the windowsill in a way that helps them sit partially below the window. Either way, it’s important to note that your window will be partly open and must be locked in that position for home security.

Each window AC model will come with instructions for proper installation. You can follow them on your own or schedule an appointment with Best Buy’s professional appliance installation team.