How often you should replace your air filters can depend on the following:
- Air filter type
- Overall indoor air quality
- Number of pets
- Household size
- Air pollution levels and construction around the home
For basic 1"–3" air filters, manufacturers often instruct you to install new ones every 30–60 days. If you suffer from light to moderate allergies, you could get a better air filter or change them even more regularly.
Or, if you reside a more rural location or less occupied house (like a vacation home) and there are fewer cars around, yearly may be regular enough.
Here are averages that can help you know how frequently you should change the air filter at your house:
- Vacation home 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