Check your HVAC air filter every month—defer to your owner’s manual for where filters are located—and wait no longer than 90 days to replace if you see an issue.

Variable Air Flow for Heating, Ventilation and Air Conditioning Systems A variable air volume box controls the air flow to a given space. When the space is unoccupied, the box closes off the heat and ...

There are a few things to keep in mind when determining how often you should change your the air filters on your heating and cooling systems.