How to replace your HVAC air filter

Source: Trane: Discovering Your Air Handler Filter Location · Last checked 2026-10-21

Replace the air filter on your air handler. The source says: in general, plan on changing the air filter every 30-90 days.

Steps

  1. Find the air filter: it is in a built-in 1" filter frame on the air handler, in a compartment next to the air handler, or at a return air vent in a wall or ceiling.
  2. When you remove the old filter, check the measurements listed on its frame. If it fit well, look for those measurements when buying replacement filters.
  3. If you don't see measurements on the filter, measure its length, width, and depth with a measuring tape. If there is no old filter, measure the filter compartment.
  4. Round off to the nearest whole number to get the standard size.
  5. Open the filter compartment or return air grill.
  6. Remove the old filter.
  7. Place the new filter in the slot with the arrow facing into the wall, ceiling, or air handler.
  8. If the filter doesn't have an arrow but has a metal mesh side, place it so the metal faces the return air duct in the wall or ceiling, or faces the air handler.

Questions

How often should I change the HVAC air filter?

In general, you should plan on changing the air filter every 30-90 days, according to Trane.

What happens if the filter is dirty?

According to Trane, a dirty filter makes your HVAC system work harder, potentially leading to higher energy bills and early system breakdown.

Which way does the new filter face?

Place the new filter in the slot with the arrow facing into the wall, ceiling, or air handler. If it has no arrow but has a metal mesh side, the metal faces the return air duct in the wall or ceiling, or faces the air handler.

Also from the source. If you have a whole-house air cleaner, you may have to work with your HVAC professional to get replacement filters.

Models vary, check your manual. These steps come from Trane: Discovering Your Air Handler Filter Location and HouseHack doesn't verify them. Follow your appliance's manual and safety labels.

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