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