How regularly you should change your air filters can depend on the following:
- Air filter model
- Complete indoor air quality
- Number of pets
- Household size
- Air pollution levels and construction around the home
For basic 1"–3" air filters, manufacturers typically 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 regularly.
Or, if you're in a more rural area or less occupied home (like a vacation house) and there are not as many cars around, every year may be regular enough.
Here are averages that may help you decide how often you should replace the air filter at your house:
- Vacation house 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