Turn off the breaker, remove the bathroom fan grille, and swap the motor with a genuine replacement kit that matches your fan’s exact model and housing size.
Whirring, buzzing, or dead bath fans usually need a new motor, not a whole new fan assembly. The slightly larger size of most replacement motors means the housing dimensions and model number decide which kit fits. That step matters because Broan-NuTone’s own compatibility lists are strict about both.
How The Replacement Process Works
Every bath fan motor swap follows the same basic route. Shut off power at the breaker first, then remove the grille, which typically pulls straight down or has spring clips. The motor assembly sits inside the housing and disconnects with a plug or a few screws. Most genuine replacement kits include the motor, blower wheel, and mounting plate pre-assembled, so installation is literally disconnect and plug in.
The heavier RE70BN for select 70 CFM fans includes the motor, blower wheel, two mounting plates, and hardware. Before buying, verify the model number on the fan’s rating sticker plus the housing dimensions.
Matching A Replacement Motor To Your Fan
Broan-NuTone sells several genuine motor kits, and each fits a specific model and housing-size range. Ordering the wrong one prevents installation, so match both numbers before checkout.
| Replacement Kit | CFM Rating | Fits These Models / Housings |
|---|---|---|
| BP27R | 50 CFM | Broan 662, 668, 678, 688 series; Nautilus N678/N688 |
| RE70BN | 70 CFM | Broan 670, 671, 688, 689; NuTone 693, 695, 696N; housings 7-1/2 x 7-1/4 up to 8-1/16 x 7-3/8 |
| C380BN | 80 CFM | Broan/NuTone models 576, 685, 755, 763, 770, 784 and more; 8 x 8-1/4 housings only |
| S97017705 | 100 CFM | Broan-NuTone 8663RF, 8673RP, VL3668RLG and related 8663/8673 models |
| S89615000 | 90-110 CFM | Motor only; VL3668MAB, 8663F, 8673P, 8814 and select NuTone models |
The RE70BN works with housings sized 7-1/2 x 7-1/4, 8 x 7-1/4, and 8-1/16 x 7-3/8, but Broan-NuTone states it does not fit 8 x 8-1/4 housings. The C380BN, by contrast, requires an 8 x 8-1/4 x 5-3/4 housing and fits only Broan or NuTone fans, not other brands. The S97017705 kit for 100 CFM fans ships with a pre-assembled motor, blower wheel, and mounting plate, while S89615000 is motor-only for select 90/100/110 CFM models.
If you know the fan model but aren’t sure which kit applies, Broan-NuTone’s motor and wheel compatibility page lists the genuine options by model. For a curated list of proven motors and complete replacement units, our bath fan motor roundup tested for real-world performance breaks down the best fits by CFM and housing size.
Two practical notes before installing: replacement kits are not universal, and several high-power options are upgrades rather than exact clones. A motor-only part that fits a plug-in assembly still requires power to be off at the breaker before the housing opens.
When A Noisy Or Slow Fan Needs More Than A Motor
A noisy bath fan sometimes has a clogged vent or a worn bearing that sounds worse than it is. Remove the cover and spin the wheel by hand: if it turns freely and the noise continues after a motor swap, the housing or duct needs attention. Broan-NuTone markets these kits as replacements for fans that are “no longer working properly, noisy, or needs an upgrade,” but that assumes the housing and ductwork are sound.
FAQs
Can I install a bath fan motor without calling an electrician?
Yes, for most Broan-NuTone fans. The BP27R and RE70BN kits use plug-in motors, so no wiring is involved beyond disconnecting the old plug. Still disconnect power at the breaker before opening the housing, and confirm the replacement part matches the fan model stamped on the rating label.
What does housing size have to do with motor compatibility?
The motor mounts into the metal housing, so a motor built for a taller or narrower housing will not line up with the mounting holes. Broan-NuTone lists housing dimensions with each kit, like 8 x 8-1/4 for the C380BN, and those dimensions are as important as the model number.
Will a higher CFM motor make my bathroom fan vent better?
Sometimes. If the current duct is undersized, kinked, or long, the motor cannot overcome it, so inspect the duct run before expecting a dramatic difference.
References & Sources
- Broan-NuTone. “Bath Fans: Motors & Wheels — Genuine Replacement Parts” Official parts hub for BP27R, RE70BN, C380BN, and other genuine replacement kits.
- Broan-NuTone. Replacement Parts Shop Source for motor-only and motor-kit configurations across Broan and NuTone model lines.
- Broan-NuTone. “BP27R — 50 CFM Bathroom Fan Replacement Motor/Wheel” Product page confirming plug-in installation, ten-minute install time, and model compatibility.
