|This may not be of interest on AFCA, but I wanted a window fan that was not cheap plastic (impossible to clean), low 'sones' (noise level), and high CFM. My solution was converting a Broan L200 exhaust fan. It is intended for recessed ceiling mount, running without maintenance continuously with 20 year expected life. This is 210 CFM, 1.7 sones with variable speed control. Compare that to any window fan on the market and this CFM and low sone level does not exist. My steps:1. I raised the double hung window sash, measured inside the jamb recess for the window, placed flexible round insulation foam tubes inside, and cut the MDO (waterproof) board to fit as tight as possible with give to squeeze the board in.
2. Cut the mfr spec hole to fit the fan and spray painted the MDO board both sides.
3. Although galvanized steel, the housing is not intended for exterior use and has holes. To permanently waterproof I sealed the motor opening side of the housing so paint would not into the interior, turned it open side down, cut small pieces of duct tape to cover all clip joint holes in the housing, and spray painted it with 4 coats of gray 'Flex Seal' rubberized coating.
4. I screwed the fan housing to the MDO board with stainless steel screws (not visible with the included grille cover), protected the painted side with towels and turned it face down on my bench.
5. Connected electrical with conduit and an exterior 90 degree accessible elbow, drilled a hole thru for the variable switch inside and mounted all that. Then I spray painted the entire exterior again with the Flex Seal, conduit, MDO board and housing.
6. I Took the assembled unit and squeezed it into the window jamb recess with the foam insulation. Then took the conduit elbow cap off and did final wiring to the switch. Replaced the cap and respray that with Flex Seal.
7. Inside, I just cut a heavy duty 6 foot extension cord, wired it to the switch and plugged it in.
8. Last, I bought an 8" diam. spring exterior duct hood (have to make your own bug screen) and connected it with 12" straight round duct to prevent incoming wind flow when off.
Photos just taken after 4 years and still running smooth. All I do is a few time a year take the inside grille off, vacuum and blow thru the metal filter (carefully as they are fragile), and vacuum the inside.
Specs (all bought on Amazon):
Broan L200 Exhaust Fan (grille included)
Nutone 57W-B White, 3 amp Variable Speed Switch
Broan-Nutone LAF1 12"x12" cleanable alum. grease filter
Speedi-Products 8" Wall Vent Hood w/ Spring Damper + cut to length 8" round galv. straight duct