How frequently you should change your air filters could depend on the following:
- Air filter model
- Complete indoor air quality
- Number of pets
- Household size
- Air pollution levels and construction around the house
For basic 1"–3" air filters, manufacturers typically instruct you to replace them every 30–60 days. If you have from light to moderate allergies, you could get a better air filter or change them even more regularly.
Or, if you're in a more rural 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 might help you figure out how often you should replace the air filter at your house:
- Vacation residence or single occupant and no pets or allergies: every 6–12 months
- Common 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