How frequently you should replace your air filters could depend on the following:
- Air filter type
- 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 instruct you to change them every 30–60 days. If you have from light to moderate allergies, you could get a better air filter or change them even more frequently.
Or, if you're in a more rural area or less occupied home (like a vacation residence) and there are fewer cars around, yearly could be regular enough.
Here are averages that might help you know how frequently you should change the air filter at your house:
- Vacation home 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