How Often Should You Change a 4-Inch Furnace Filter During Winter?

Horizontal winter-themed graphic showing how often you should change a 4-inch furnace filter during winter, with 3D icons of a monthly calendar, 4-inch filter, airflow shield, and house in a blue color theme.

Most 4-inch furnace filters in hard-use winter homes run about a month longer than they should. You can’t see it happening. That’s the whole problem. After manufacturing filters for over a decade and serving more than two million households, we’ve learned that homeowners who stay on top of this aren’t doing anything heroic. They just … Read more