How often you should replace your air filters can 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 often instruct you to replace them every 30–60 days. If you have from light to moderate allergies, you could install a better air filter or get new ones even more regularly.
Or, if you reside a more rural location or less occupied residence (like a vacation home) and there are not as many cars around, yearly may be regular enough.
Here are averages that might help you know how frequently you should get a new air filter at your residence:
- Vacation residence 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