Replace a furnace filter
Turn the blower off, slide in a filter of the same size, and point the arrow the way air moves toward the furnace.
Tools you need
- A new filter in the size printed on the old one
- The thermostat
- A flashlight if the slot is in a closet
Steps
Set the system to Off at the thermostat so the blower is still while the slot is open.
Find the filter in the slot beside the blower cabinet or behind the return grille. Slide the old one out and read the size and the arrow on the frame.
Use that same size. Point the new arrow the way the old arrow pointed. Air moves toward the furnace or air handler and away from the return grille.
Slide the new filter in all the way so the frame does not buckle and air cannot sneak around the edge.
Close the door or the grille. Put the thermostat back to Heat or Cool.
Look at the filter again about once a month in heating season. A pad gray with dust is ready to change.
More heating and air jobs
Steps written by Sureno. Photos from Wikimedia Commons, credited under each one.