How regularly you should replace your air filters can depend on the following:
- Air filter model
- Complete indoor air quality
- Number of pets
- Household size
- Air pollution levels and construction around the home
For basic 1"–3" air filters, manufacturers usually instruct you to change them every 30–60 days. If you have from light to moderate allergies, you could install a better air filter or replace them even more regularly.
Or, if you live a more country area or less occupied residence (like a vacation home) and there are a reduced number of cars around, annually could be regular enough.
Here are averages that could help you decide how often you should replace the air filter at your house:
- Vacation residence 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