If, when indoors during the summer, you feel stuffy, groggy or just plain blah, look to you’re A/C unit. In between annual maintenance visits, your A/C unit should be cleaned on a regular basis. Though one of the most essential of home maintenance tips—as a clean unit can provide your home with fresh, breathable air—cleaning the unit is relatively simple. This is the case for both window and central A/C units.

Before you turn your unit on at the start of summer, wipe down the vents with a wet rag. Next, turn off the unit, remove the grille and clear the debris out of the interior. Window units especially tend to collect twigs, leaves, pollen and dirt. Use a vacuum hose to get the dust out of hard to reach places. If you want to get down to the nitty-gritty, use the hose to unclog the AC drain line, which is the small line near the ground. Finally, to keep the unit running efficiently all season long, keep it clear of shrubs and debris.