3 of 3 people found the following review helpful
Possible to install from the bottom,
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This review is from: Air King BFQ 50 Energy Star High Performance Bath Fan, 50-CFM (Tools & Home Improvement)
I replaced a builder-grade unit Broan-NuTone 696N 50 CFM, 4.0 Sones. Fan 3" Duct with this larger and much quieter one (the 50-cfm version) in a ceiling without back-side access. It was tricky, but doable. It would have been much easier in an attic space with access from the top.
After disconnecting the power, I removed the old fan motor and had to pull out the metal box by force - since the new one is larger, I could have cut a little around it but I didn't have to. Next, I cut out the new larger size opening. I replaced the first section of old 3" vent tube with a larger piece of 4" rigid vent. I then installed the bracket that the fan box clicks into. The fan is designed so it can vent either way parallel to the beam the bracket is mounted on. Next, I connected the wiring, and worked the fan box up into the opening and clicked into the bracket.
Then the tricky part - work the vent tube onto the 4" opening from the inside. You can't attach it before putting the box up or it would be too large to get into the opening. I had to remove and replace the one-way air flap from the vent opening in the box - no easy task with my large hands, but I finally got it done. Then, put in the fan motor and attached the cover.
Oddly, the cover is larger than the opening and looking up you can see the painted ceiling around the rectangular cut-out area through the slits in the vent cover. But it looks OK and works great. Peace and quiet at last!
The fan is so quiet now it's hard to tell it's on. The motor hum is slightly audible as the air noise is almost nil. In the shower I can't hear the fan at all. Next time I'll try the 70-cfm unit.