How to Change the Filter in Your Furnace
Locate the furnace filter compartment.
You can usually find it near where the cool air enters the furnace — the air return duct or at the entrance to the blower chamber. Sometimes there’s a filter in both locations.
Slide out the old filter.
The filter should slide out easily. If there’s any resistance as you pull, check to make sure that there is a locking mechanism holding it in place. If so, slide the lock out of the way and it should slide right out.
Disposable furnace filters have a cardboard frame. If your filter has either a plastic frame or a metal one, stop here. It is a permanent filter and can be cleaned and reused instead.