so here i go to one of what i thought was an important account. contract calls for pleated filters at all locations which I'm sure is fine . . . when the filter is actually doing something. anyway the guy referred to as "the best" even though he really sucks has been here plenty of times before & guess figured all was well with this setup. evap & blower wheel was starting to accumulate layers of dust & ironically the diffusers & surrounding ceiling tiles were dirty. the gap was the same on both sides of the before. the after, well speaks for itself . .