How do I know my air filter size?Updated a month ago

You can find your air filter size in three ways (just remember to turn off your HVAC before doing any of these 😄): 

Check the frame of your old filterMost common. The size should be printed on it. If there are two measurements, use the rounded up figures as your reference.

Measure your old filter With a tape measure, if it does not have the size printed on it. After that, take your measurements and round them up to the nearest inch. 

Measure your filter slotWith a tape measure, if for some reason you cannot measure your old filter. After that, take your measurements and round them up to the nearest inch.

Why round up? Learn more here.