How often you should install new air filters can depend on the following:
- Air filter kind
- Total indoor air quality
- Number of pets
- Household size
- Air pollution levels and construction around the residence
For basic 1"–3" air filters, manufacturers usually tell you to replace them every 30–60 days. If you deal with from light to moderate allergies, you could install a better air filter or replace them even more frequently.
Or, if you live a more country spot or less occupied house (like a vacation residence) and there are a reduced number of cars around, every year may be frequent enough.
Here are averages that might help you figure out how often you should replace the air filter at your house:
- Vacation home or single occupant and no pets or allergies: every 6–12 months
- Common 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