How regularly you should change your air filters could depend on the following:
- Air filter model
- Overall indoor air quality
- Number of pets
- Household size
- Air pollution levels and construction around the residence
For basic 1"–3" air filters, manufacturers usually instruct you to install new ones every 30–60 days. If you suffer from light to moderate allergies, you could get a better air filter or get new ones even more often.
Or, if you live a more country location or less occupied residence (like a vacation home) and there are a reduced number of cars around, annually may be regular enough.
Here are averages that could help you decide how frequently you should change the air filter at home:
- Vacation home 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