How regularly you should install new air filters could depend on the following:
- Air filter kind
- Overall indoor air quality
- Number of pets
- Household size
- Air pollution levels and construction around the home
For basic 1"–3" air filters, manufacturers typically tell you to get new ones every 30–60 days. If you have from light to moderate allergies, you could install a better air filter or replace them even more often.
Or, if you live a more country area or less occupied house (like a vacation house) and there are not as many cars around, annually could be often enough.
Here are averages that can help you decide how often you should get a new 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