How to Find Your System's Air FiltersChecking your HVAC system’s air filter is an important monthly chore, so you can replace it when there’s any visible dirt accumulation, or at least every three months. Clean air filters are better able to trap debris so airflow doesn’t get restricted and your system stays running efficiently and reliably. Before you can check and change your air filter though, you need to know how to find it.

Where to Look for Hidden HVAC Filters

If you’re not sure about the exact location of your air filter, here are some helpful tips on where it might be hiding:

  • Inside the blower unit cabinet. This is the cabinet that houses your cooling system’s evaporator coil and your furnace, and it might be located in your basement, attic or a utility closet. Depending on your specific HVAC model and its configuration, the filter may be sited on the top, bottom or side of the unit. The filter might slide into a slot adjacent to the main return air duct/cabinet connection, or behind an access panel. If you have a larger HVAC system or zoned units, you may have two or more filters instead of just one.
  • Inside your whole-house air cleaner unit. If your system has an air cleaner unit added, it’s likely mounted alongside the air handler/main return duct, and you’ll typically find the filter located inside.
  • In a return duct opening. Some HVAC systems have filters located just behind a return air You may have to check all such grilles in your home – typically, they’re found in central locations either on the floor, wall, or ceiling.

Tips for Replacing Your Filter

Once you’ve found and removed the existing filter, make sure you choose a replacement that matches your equipment manufacturer’s recommended size and MERV rating, because:

  • Gaps around a too-small filter can let debris into your HVAC system.
  • Too high a MERV rating can cause airflow restrictions that damage your HVAC equipment.

For personalized help locating your filter, or for advice about the right air filters for your HVAC system, contact us at Mowery Heating, Cooling and Plumbing.

Our goal is to help educate our customers in Brownsburg, Indiana and surrounding areas about energy and home comfort issues (specific to HVAC systems).