How to Replace Your Furnace Air Filter the Right Way

Time required: 5-10 mins · Difficulty 1/5

Est. DIY Parts: $6 - $25 · Pro Service: $75 - $150 · Est. Savings: $55 - $140

* Estimates based on regional/national contractor rate benchmarks. Actual part prices vary by brand and retailer.

Parts & Tools You'll Need

Find your filter size Check the printed dimensions on the edge of your current filter, or measure the filter slot directly — width x height x depth.
Turn off the furnace Switch your thermostat to 'off' so the blower doesn't kick on while the filter slot is open.
Slide out the old filter Open the filter door or panel (usually near the return air duct or blower compartment) and slide the old filter straight out.
Check the airflow arrow Look for the printed arrow on the frame of the new filter — it must point in the direction of airflow, toward the blower/furnace, not back toward the room.
Insert the new filter and close up Slide the new filter in fully until it seats flush, close the access panel, and turn your thermostat back on.