How Often Should You Change Your Air Filter? (By Household Type)
The boxes say "up to 90 days." The truth depends on your house. Here are the schedules our techs actually recommend, based on what we pull out of furnaces across western Kentucky every week.
Replacement schedule by household
| Your household | 1-inch filters | 4-5″ media filters |
|---|---|---|
| No pets, no allergies, 1-2 people | Every 90 days | Every 12 months |
| One pet, or light allergies | Every 60 days | Every 9-12 months |
| Multiple pets, kids, or real allergies | Every 30 days | Every 6-9 months |
| Smokers, wood stove, remodel dust, or wildfire season | Every 30 days | Every 6 months |
What happens when you forget
A clogged filter is not a cosmetic problem. In order of what we see in the field:
- Airflow drops and rooms get uneven. The far bedrooms stop getting cool air first.
- Energy use climbs. The blower works harder against the clog; typical penalty is 5-15% on the HVAC portion of your bill.
- The evaporator coil can freeze. Restricted airflow over the coil in cooling season causes ice-ups, one of the most common "my AC stopped cooling" service calls we run in July.
- Blower motors die young. Motors are cooled by the air moving through them. Years of clogged filters is how a $20/year filter habit becomes an $800 motor.
Two ways to never forget
The free way: change it when your utility bill arrives, or set a phone reminder for the first of the month and check it, if you can't see light through it, change it.
The automatic way: our Filter Club subscription delivers on your schedule, every 1, 2, 3, or 6 months, so the fresh filter showing up is the reminder. Any sizes, any quantity, from $7.99 per filter delivered, and your first shipment is 20% off.
Does a higher MERV change the schedule?
Yes, slightly. Higher-MERV filters capture more, so they load faster. Our MERV comparison guide covers it, but the short version: whatever the rating, a filter changed on time beats a better filter changed late.