I can't seem to locate the filter to change it on a Day & Night Furnace? Two blue panels on the lower front and only the upper panel comes off and that's where the pilot lights and stuff are. I need to change the filter for the air conditioning and it's a combo unit. Thanks, J

Not sure on day and night but do you have a return grill maybe in hallway? Check there. Also it could be under the panel inside unit where the return air enter the coil compartment.Someone else may be along that is more familiar with this unit.

The bottom panel should slip upwards and off to expose blower and filter. Mike

The bottom panel should slip upwards and off to expose blower and filter. Mike

Correct answer was probably most appreciated! Do you also know where I can buy an upgraded filter, with frame, not matting as in the old one?

I cannot locate the filter on my Day and Night furnace and air conditioner, it is all
One unit. It was installed in about 1997.