How frequently you should change your air filters could depend on the following:
- Air filter kind
- Total 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 replace them every 30–60 days. If you suffer from light to moderate allergies, you could install a better air filter or get new ones even more regularly.
Or, if you live a more rural spot or less occupied home (like a vacation residence) and there are not as many cars around, annually could be often enough.
Here are averages that may help you figure out how frequently 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 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