How often you should change your air filters might depend on the following:
- Air filter kind
- Overall indoor air quality
- Number of pets
- Household size
- Air pollution levels and construction around the residence
For basic 1"–3" air filters, manufacturers typically tell you to replace them every 30–60 days. If you deal with from light to moderate allergies, you could get a better air filter or replace them even more often.
Or, if you're in a more rural area or less occupied residence (like a vacation home) and there are fewer cars around, annually might be often enough.
Here are averages that could help you decide how frequently you should change the air filter at your house:
- Vacation house or one occupant and no pets or allergies: every 6–12 months
- Ordinary suburban house without pets: every 90 days
- One dog or cat: every 60 days
- More than one pet or if anyone has allergies: 20–45 days