How frequently you should install new air filters might depend on the following:
- Air filter type
- Overall indoor air quality
- Number of pets
- Household size
- Air pollution levels and construction around the house
For basic 1"–3" air filters, manufacturers typically 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 regularly.
Or, if you're in a more remote spot or less occupied house (like a vacation house) and there are a reduced number of cars around, yearly could be regular enough.
Here are averages that may help you decide how often you should change the air filter at your house:
- Vacation residence or one occupant and no pets or allergies: every 6–12 months
- Ordinary 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