Questions and Answers for AAF Flanders 20 x 24 x 1 Pre-Pleat 40 Pleated MERV 8 Air Filter (12-Pack)

A:  Recommended time to replacement the 16x25x1 prepleat 40 air filter is every 90 days.

A:  I find it very interesting that the rep doesn't ask where the person is living which IMHO is very important. We lived in Seattle & changed filters every 3 to 6 months. We now live in Phoenix. During the summer we replace the filters about every 30 days. We use the less expensive because they provide better air flow. The more expensive ones restrict air flow & get plugged up with fine dust very quickly. During the winter we can waiting 60 <> 90 days because we don't have the dust in the air. Check your filter & if it is dirty change it ;-)