No matter what type of air conditioner you have, you will need to change the filter at some point. The first step will be to purchase the correct filter for your air conditioner. Your user manual will be able to help you with this step.
Window air conditioner filters are relatively easy to change. Just pop them out and put the new one in. Whole-house air conditioner filters can be hard to find and change. We recommend having an expert (like those at Russell’s) change the filter on whole-house air conditioners.