How often you should replace your 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 house
For basic 1"–3" air filters, manufacturers usually tell you to replace them every 30–60 days. If you have from light to moderate allergies, you could install a better air filter or get new ones even more frequently.
Or, if you live a more rural location or less occupied house (like a vacation residence) and there are not as many cars around, every year may be regular enough.
Here are averages that might help you figure out how often you should replace the air filter at your residence:
- Vacation home 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