How often you should install new air filters can depend on the following:
- Air filter kind
- Overall indoor air quality
- Number of pets
- Household size
- Air pollution levels and construction around the home
For basic 1"–3" air filters, manufacturers often direct you to get new ones every 30–60 days. If you suffer from light to moderate allergies, you could get a better air filter or change them 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, yearly could be regular enough.
Here are averages that might help you know 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 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