How Often to Replace Your HVAC Filter (and Why It Matters)
A dirty HVAC filter costs you comfort and money. Here's how often to swap it, how to tell it's overdue, and how to pick the right one.
Why it matters
Your HVAC filter catches dust, pet hair, and allergens before they circulate through your home. Once it clogs, your system has to work harder to push air through it — that means higher energy bills, more wear on the equipment, and worse indoor air quality.
How often to replace it
Every 90 days is a safe default for a standard 1″–3″ filter in a typical household. If you have pets, allergies, or run your system constantly during extreme weather, check monthly instead — you may need to replace it more often.
Signs it's overdue
Weaker airflow from your vents, more dust settling around the house, and a system that seems to run longer than usual to reach the temperature you set are all signs your filter needs attention. Hold it up to a light — if you can't see light through it, replace it.
How to do it yourself
Find your filter slot (usually near the return air duct or inside the air handler), note the size printed on the frame, and slide the old one out. Check the airflow direction arrow on the new filter and make sure it points toward the system, not away from it.