What does it mean when the return air filter is pushed up into the duct when replaced? It's from the pressure of the air going into the system of course, but what is that telling me exactly about my system? I use a Ultra... something 1250 Allergan? I forget the name.. One inch thick filter 14X30 inches.
I ask this because I'm co0ntemplating installing a Aprilaire media filter 2400 or similar and would like to get an idea of how things are going to work, or not work.