How to Change the Filter in Your Furnace
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.