How often 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 house
For basic 1"–3" air filters, manufacturers often tell 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 replace them even more frequently.
Or, if you live a more country area or less occupied house (like a vacation residence) and there are fewer cars around, every year may be often enough.
Here are averages that may help you know how often you should replace the air filter at your residence:
- Vacation house 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