On Mar 14, 10:39*am, "DGDevin" wrote:
"djay" wrote in message

news:m%nCj.8985$HA3.8232@trnddc02...

I'm installing a Panasonic bathroom exhaust fan - approx fan box size is
12 X 12 inches and it's replacing a POS nutone NOISE maker that has an
opening about 8 X 10.

Good call, we put a Panasonic in our kitchen and it's so quiet we have stand
under it and look to know it's running, yet it moves just as much air as the
noisy fans like NuTone. *It isn't meant as a stove vent fan so we put it in
the middle of the room and it's worked great there at dumping heat and
humidity when we're cooking.

So in my example above after the new hole is cut into the drywall fit the
larger fan, and new joist installed (parallel to the existing joist but
for the other side of the fan hole). *I'd push the new fan up through this
hole until the mounting lip rested on the ceiling. *I'd put screws in
through this lip, up into the drywall and into the joist above. *Then of
course seal in the fan from above and replace the 3" exhaust duct with 4".
Does that sound doable? * *I guess normally this lip would be between the
ceiling drywall and joist but I can't see a downside to installing it
directly onto the existing drywall.

What do you think?

That is exactly how ours was installed and it works fine, the cover more
than conceals the flange screwed to the ceiling, I see no reason not to do
it this way.

No way I'd install another joist to support a fan. It's not like
it's 200 lbs. Fasten it to the existing joist and use the joist span
brackets that came with it.

As for noise, IMO the good fans that cost $50 more, like the Panasonic
are so much quieter than the cheap crap ones that it's not worth going
beyond that with a seperately remotely mounted fan unit.