Furnace air filter replacement

[Michael Didion]

My wife and I just got AC installed in our rental and the technician said to change the filter every month. Is it really necessary to change the filter every month? I've only ever changed it about 2 times a year on our primary home. Any thoughts are appreciated.

[Kathleen Leary]

With a new unit, not following manufacturer's instructions might void an existing warranty, too.

I change the filters myself monthly. Tenants will not change them even if there's a boxful sitting there; I understand that, actually. As long as the HVAC works, what do they care? (They don't.)

I certainly care, though! I need the units to last as long as possible & if that means monthly filter changes, so be it. I've had tenants tell me they actually appreciate my doing it; shows I care about the property.