How regularly you should replace your air filters might depend on the following:
- Air filter type
- 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 install new ones every 30–60 days. If you have from light to moderate allergies, you could upgrade the air filter or replace them even more often.
Or, if you're in a more remote spot or less occupied house (like a vacation house) and there are not as many cars around, every year could be regular enough.
Here are averages that may help you figure out how often you should change the air filter at your house:
- Vacation residence or lone occupant and no pets or allergies: every 6–12 months
- Average suburban home without pets: every 90 days
- One dog or cat: every 60 days
- More than one pet or if anyone has allergies: 20–45 days