Just like a car engine’s air filter, the filter on your air conditioning unit should be changed and serviced regularly. Clogged ac air filters not only decrease in effectiveness, but also result in higher energy use and can contribute to an abundance of allergens in the air. Most AC filters have recommended guidelines for how often you need to change them right on the package, but in general, once every month or two is fine during the cooler months when you aren’t using the unit as often.

During hotter weather, when you use the AC frequently, you may need a new filter every few weeks. You may also need to replace the filter more often if you have pets that shed a lot, as their fur can get into the vent system. At minimum, you should change the filter once every three months. To be more cost effective, look into purchasing a filter than can be cleaned and reused rather than one that has to be thrown away.