I would like to replace a 'disappointing' bathroom ceiling exhaust fan with some other brand, but have the challenge of predicting what is compatible with the existing drywall cutout. Few online manuals tell the cutout size - they just say to use the template or the housing to mark the cutout required)

It's a round fan/light (NuTone 8664RP) with 13-1/4" circular ceiling drywall cutout, and a 15" grille. May be same as Broan 750, but the Broan manual implies using the housing to draw the opening required, while the NuTone specs do call out 13-1/4" opening. I compare them just for reference. Broan & NuTone are part of the same company. The Broan one has a night light.

Basically, what I'm asking is whether anyone else has done this. Online reviews clearly show unhappiness with the 8664RP performance, so maybe someone found a solution.

  • IMHO, if at all possible, replace this end with a simple grille and get an inline, remote fan placed further up the duct, if "not disappointing" is your desired result.
    – Ecnerwal
    Dec 1, 2014 at 16:33

1 Answer 1


I haven't worked with these exact units but they should have pretty similar requirements. I was able to find a diagram on the Broan website for the 750 that allowed me to extrapolate the size of the cutout. enter image description here Bear in mind there's a bit of margin for error in this trick but as you can see, the diameter of the cutout would be roughly 13 1/2". You may have to ream out your drywall a bit but that's better than having a hole that's too big. And remember your grill is 15" so you'll have aprx. 3/4" of fudge room all around. In all likelihood the drywall cutout won't be an issue, but you'll probably have to modify the blocking to accept the new unit, which (as long as your framing is as it should be) won't be too much hassle.

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