Just got the shop air filter done. There are three 2 inch thick MERV 11 filters and one 1 inch thick MERV 4 filter. Air is drawn through the MERV 4 filter which is in the 1st photo, then through the three MERV 11 filters in the 2nd and 3rd photos and is then blown down osb ducts to the ends of the shop, you can see one of these ducts in photo 4. Photo 5 shows about the same as photo 3 with some plywood filter holders removed. These are removable so that filters can slide out for cleaning or replacement and also so the blower/motor can also slide out if needed. The blower is attached to a piece of 3/4 ply that slides in a track so that it can be removed and is held in place with a bolt and nut on each side. Man was it a pain lifting that thing up to the ceiling. The wiring is shown in the last photo, the orange cord just plugs in and is temporary, this will be hard wired later at the junction box which is shown in photo 3 and there will be a switch with timer down below.