We suggest checking filters monthly. If you have a disposable type filter, (these usually have a cardboard edge), and if it is dirty, just replace it. Don’t attempt to clean it. Some higher efficiency 1″ pleated air filters can go up to three months before needing replacement. But in the higher-use seasons, it’s better to check more often.
Different systems have different filter locations. If you don’t know where your filter is located, now would be a good time to learn! Usually, there is a removable filter access door in the return air duct next to the furnace or indoor unit. This can be in a basement, crawl-space, utility closet, garage, or attic.
Sometimes, especially with older systems, the filter is located inside the furnace itself, next to the blower motor. And some systems have a central filter grille installed in a wall or ceiling. The grille swings open, revealing the air filter.
- Some systems, especially larger ones may have more than one air filter. They can even be different sizes.
- If you have more than one heating and/or air conditioning system, then you definitely have more than one air filter