How frequently you should replace your air filters may depend on the following:
- Air filter type
- Complete indoor air quality
- Number of pets
- Household size
- Air pollution levels and construction around the residence
For basic 1"–3" air filters, manufacturers usually direct you to replace them every 30–60 days. If you have from light to moderate allergies, you could install a better air filter or get new ones even more regularly.
Or, if you're in a more country area or less occupied home (like a vacation house) and there are not as many cars around, annually might be often enough.
Here are averages that could help you decide how often you should get a new air filter at your house:
- Vacation house or single occupant and no pets or allergies: every 6–12 months
- Common 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