My inspection yesterday sent me into shock when I opened the furnace closet door there set the Heat pump A-coil directly on top of the furnace it was not within a enclosed box. The return air filter was in place approximately 2 feet above the coil simply slid into a built in slot on the 2X4 wall studs. The return air was bypassing the filter at the bottom of the closet door. What amused me the most was the owner had a wire brush lying near the coil to clean off the lint when ever they remembered to do it.
Every time I think I have seen it ALL something else like this pops up. I guess I won’t live long enough to see it all.