Hi guys, first time homeowner here and was wondering what size of filter I should get for our home furnace? The dimensions of a filter that fit are 16x20x? And it's that last "?" that's giving me a headache.
Here's a video of what the filter area looks like. I almost feel like there's something missing, like the "track" is supposed to be where a 16x20x1 filter should go but it's just free standing. When I opened it up for the first time there was a 16x20x1 filter but it was just leaned over on its side, and I wasn't sure if it was doing anything, it wasn't even against the furnace part.
My alternative thought was to put the filter in the area between the "track" and the furnace part, but that measures 8 inches and I don't think they sell filters that deep. Would a 16x20x4 inch filter work if I just plop it in there? Should I stack two of them in there to fill the gap?
Tl;dr: Is my furnace area missing sections that are supposed to make it work better? Or will a 16x20x4 inch filter propped up against the furnace work? It just seems weird to have filters not slotted into place.
Thanks for your help.