Our readers keep the lights on and my morning glass full of iced black tea. As an Amazon Associate, I earn from qualifying purchases.9 Best Bathroom Fan Motor | Match The RPM Before You Buy

Specs are compiled from manufacturer listings and verified buyer reviews and can change over time — please confirm the key details on the product page before buying.

Your bathroom fan grinding, rattling, or humming like a trapped bug is almost never a dead fan — it is a tired motor, and swapping just that part costs a fraction of a whole new unit. The trick is matching three numbers on your old motor: airflow in CFM, noise in sones, and speed in RPM. Get those right and the job takes about ten minutes with no wiring and no drywall cutting. Get them wrong and you are fighting a blade that will not clear the housing. This guide covers the nine replacement motors worth your money, what each one actually fits, and which trade-off you are accepting.

I’m Mohammad Maruf — the founder and writer behind KitchPrep. This guide is built by comparing the manufacturers’ published specifications and the patterns across verified customer reviews, so you get each pick’s real strengths and trade-offs instead of marketing spin.

Replacement motors are cheap, but the wrong one wastes a weekend — so match your part number first, then weigh airflow against noise. Here is what actually matters when you shop for a bathroom fan motor.

Our Picks at a Glance

89850000 S89850000 Bathroom Exhaust Fan Replacement Motor & Blower Wheel
Best Overall89850000 S89850000 Bathroom Exhaust Fan Replacement Motor & Blower Wheel4.7★141 ratingsA 70 CFM motor-and-blower-wheel kit that swaps in without pulling the housing from the ceiling. This is the pick for anyone staring at a fan that still hangs from the ceiling but no longer pulls steam.Check Price on Amazon
BOJACK Bathroom Vent Fan Motor 120V 60Hz 0.60A 30W Compatible with 686,687,8870,M686 YJF6158
Most PowerfulBOJACK Bathroom Vent Fan Motor 120V 60Hz 0.60A 30W Compatible with 686,687,8870,M686 YJF61584.4★652 ratingsThe 3500 rpm motor for reviving vintage 686, 687, and 8870 fans. If your fan was installed before anyone in the house was born, this is where the search usually ends.Check Price on Amazon
【Upgrade】 C350BN B Unit 50CFM Fan, Compatible with Nutone 696N(695), 2.0 Sone
Quietest Pick【Upgrade】 C350BN B Unit 50CFM Fan, Compatible with Nutone 696N(695), 2.0 Sone4.4★257 ratingsA 2.0-sone, 50 CFM motor for Nutone 696N and Broan boxes near a bedroom. Two sones is the quiet end of this list, and that single number is the whole reason to buy here.Check Price on Amazon

How To Choose The Best Bathroom Fan Motor

A bathroom fan motor is a small shaded-pole or C-frame electric motor that spins a blower wheel inside the housing already bolted to your ceiling. You are not buying a fan — you are buying the spinning heart of the one you already own. That is why the part number on your old motor matters more than any spec on a listing page. Find it first, then use the numbers below to confirm the match.

Start With The Part Number, Not The Brand

Every motor here lists the exact part numbers it replaces. Your old motor has a stamped number you can read once the grille is off and the housing is exposed. If your number is on the replacement’s list, the shaft, plug, and mounting plate almost certainly line up. If it is not on the list, do not gamble on a “close enough” motor — the plug orientation and shaft length are the two things that most often turn a ten-minute job into an afternoon of drilling.

Match The Airflow To Your Bathroom Size

Airflow is measured in CFM, or cubic feet per minute — the volume of air the blower moves out of the room each minute. A 50 CFM motor suits a small powder room or half bath. The 70 CFM and 100 CFM options here move noticeably more air, which matters in a full bath with a shower where steam builds fast. Going higher than your housing was designed for buys you nothing but extra noise if the vent pipe cannot carry the air away.

Understand Sones Before You Buy A Louder Motor

A sone is a unit of perceived loudness — one sone is roughly the sound of a quiet refrigerator, and every added sone is a clearly audible jump in volume. A 2.0-sone motor is a whisper you will forget is running. A 6.0-sone motor announces itself every time you flip the switch. A review summed up the 6.0-sone kit bluntly: “Terrible for a small bathroom. Will startle you when it starts.” Decide how much noise your household will tolerate before you chase extra airflow.

Check The Shaft, Plug, And Mounting Plate

Three physical details decide whether the motor physically goes in. Shaft diameter and length must match so the old blower wheel slides back on and sits at the right height. The plug style — two-prong versus three-pin — must match the receptacle already wired into your fan. And the mounting plate has to bolt to the bracket already screwed to your housing. Many kits include motor plates and hardware; some expect you to reuse your old bracket.

Decide if you need The Blower Wheel Too

Some kits ship as a motor-and-blower-wheel assembly, so you replace the plastic fan cage along with the motor. Others are motor-only and assume your existing wheel is still sound. If your old wheel is cracked, warped, or has a worn hub, a kit that includes a new one saves you a second order. If your wheel is fine, a motor-only kit is perfectly adequate.

Quick Comparison

Model Best For Airflow Noise (Sones) Speed (RPM) Amazon
89850000 S89850000 Motor & Blower Wheel★ Best Overall Restoring an older NuTone fan without touching the ceiling 70 CFM 3.0 Sones 3000 rpm Amazon
BOJACK Bathroom Vent Fan Motor 686/687/8870Most Powerful 40-year-old fans that need a stronger motor 3500 rpm Amazon
Upgrade C350BN B Unit 50CFM FanQuietest Pick Quiet replacements for Nutone 696N and Broan boxes 50 CFM 2.0 Sones 1450 rpm Amazon
2 Pack SM550 Universal Fan Motor Two fans to fix at once, or one spare on the shelf 50 CFM 3000 rpm Amazon
S0503B000 50 CFM 9×9 Inch Motor Fans with an integrated light and a 9×9 housing 50 CFM 2.0 Sones 770 rpm Amazon
Broan-NuTone RE70BN Motor Kit Genuine OEM parts and a jump from 50 to 70 CFM 70 CFM 6.0 Sones 3000 rpm Amazon
Upgrade 8664RP 8663RP Nutone Motor High-airflow showers and 6445RP/8673RP units 100 CFM 3.5 Sones 1480 rpm Amazon
Upgrade Model 671 Fan for Nutone 671/672 671 and 750-series fans that need real pull 90 CFM 3.5 Sones 3000 rpm Amazon
Endurance Pro 3.3 Inch Vent Fan Motor Vintage Nutone and Broan motors with the 40933 number 1550 rpm Amazon

In‑Depth Reviews

★ Best Overall

1. 89850000 S89850000 Bathroom Exhaust Fan Replacement Motor & Blower Wheel

Our pick — over 4.5★ from 100+ verified ratings; the strongest balance of quality and price.

70 CFM And 3.0 SonesMotor And Blower Wheel Kit

A 70 CFM motor-and-blower-wheel kit that swaps in without pulling the housing from the ceiling.

This is the pick for anyone staring at a fan that still hangs from the ceiling but no longer pulls steam. It spins at 3000 rpm off a 120-volt, 60 Hz supply, and it ships as a motor plus blower wheel assembly rather than a bare motor.

The part that wins people over is how painless the swap is. You do not pull the whole unit out of the ceiling — the replacement slants into place and the wiring plugs straight back in. That is the single biggest reason this one takes the top spot for most households. The unit fits a long list of Nutone models including the 665RP, 665RF, 668RP, 9965, 605P, and 605RP series, and it replaces part numbers 89850000 and 89321000.

Here is the honest catch. Noise is genuinely split — some owners find it noticeably quieter than the fan it replaced, while others get a louder result than they expected, because the blower wheel and the housing together decide the sound, not the motor alone. At 3.0 sones (a sone is a unit of perceived loudness; a refrigerator hum is about 1 sone), this is not a whisper motor. One owner’s verdict on the whole package is the one to remember: “This aftermarket NuTone fan motor & blower wheel assembly was easy to replace. The quality seems very good. It fits perfectly, works well & is very quiet.”

Why It Takes The Top Spot

  • Moves 70 CFM against the C350BN’s 50 CFM — that is 40% more air out of the room
  • Includes the blower wheel, so you replace the fan cage and the motor in one go
  • Swaps in without pulling the housing down from the ceiling
  • Replaces 89850000 and 89321000 and fits a wide spread of Nutone 665/668/9965 fans

What To Weigh First

  • 3.0 sones is not a quiet fan — light sleepers in an adjacent bedroom will hear it
  • Noise results vary depending on how your existing housing and vent pipe mate up
  • You reuse your own mounting bracket, so a bent original bracket will not help you

Reach for this one if: your fan housing is staying put and you want more pull plus a fresh blower wheel in a single ten-minute job.

Look elsewhere if: silence is the whole point — the 2.0-sone options lower on this page are the quieter route.

Most Powerful

2. BOJACK Bathroom Vent Fan Motor 120V 60Hz 0.60A 30W Compatible with 686,687,8870,M686 YJF6158

3500 RPM6.5-Inch Wire With 2-Prong Plug

The 3500 rpm motor for reviving vintage 686, 687, and 8870 fans.

If your fan was installed before anyone in the house was born, this is where the search usually ends. The BOJACK turns at 3500 rpm (revolutions per minute — how fast the shaft spins) — the fastest motor on this list, against the C350BN’s 1450 rpm — and it is a metal-bodied unit rated for 120 volts at 60 Hz (standard household AC power) with a 30W draw at 0.60 amps. Mounting studs sit 1.882 inches on center, the wire runs 6.496 inches to a two-prong plug, and the motor replaces the 686, 687, 8870, and M686 part numbers.

The kit ships with the motor and a 6.6-inch flat paddle fan, so you are not hunting for a separate blower wheel. What people report most is simply that it works — including a rebuilt 40-year-old Miami-Carey ventilator where it dropped onto the old bracket and out-performed the original on air movement. Installation is a straight unplug-and-swap for most fans.

Two honest notes before you commit. The plastic paddle has less pitch than the old metal blades on some vintage fans, and one 45-year-old NuTone 8870-A owner found the blades only barely cleared the housing — it ran quieter but moved less air in that specific box. The larger recurring concern is the blade itself, which has sheared off for a handful of buyers. It has UL and CSA certification (independent safety approvals), which is worth knowing if your insurer ever asks about the part inside your ceiling.

Where it earns its place: the 3500 rpm speed is the reason this motor can revive a fan that sounds like it is dying, and the metal housing shrugs off years of damp bathroom air.

The fit catch: measure your housing clearance before ordering — a paddle that clears by a hair on a bench can foul the housing once bolted in.

Best for: older 687/8870 fans where the original motor is long gone and you need raw speed back.

skip it if: your fan uses a small housing, since the wider paddle may want clearancing.

Quietest Pick

3. 【Upgrade】 C350BN B Unit 50CFM Fan, Compatible with Nutone 696N(695), 2.0 Sone

2.0 SonesPure Copper Motor

A 2.0-sone, 50 CFM motor for Nutone 696N and Broan boxes near a bedroom.

Two sones is the quiet end of this list, and that single number is the whole reason to buy here. The C350BN moves 50 CFM at 2.0 sones — half the measured loudness of the 6.0-sone Broan-NuTone kit further down, and noticeably below the 3.0-sone S89850000 in the top slot. It is built around a pure copper motor rather than the aluminum-plated-copper design common in older OEM units, and the blade spans an 8-inch by 7 1/8-inch footprint.

Fitting a Nutone 696N(695) or a Broan box is a matter of pulling the vent cover and clips, backing out the one screw holding the motor bracket, unplugging the receptacle, and sliding the new unit in. Buyers report the whole thing takes about ten minutes. The Motoasis unit carries a three-year manufacturer defect replacement service.

Two small things to know. Some buyers find the fit tight against the housing before it seats — it goes in, but plan for a firm press rather than a drop-in. And a few report sharp edges on the sheet metal, so a pair of gloves saves your knuckles. Neither is a reason to pass; both are worth a minute of prep before you start.

What Buyers Keep Coming Back To

  • 2.0 sones versus the 6.0 sones of the OEM kit — a big real-world drop in noise
  • Pure copper motor built for a longer service life than the older aluminum-plated design
  • Single-screw bracket and plug-in receptacle make it a genuine ten-minute swap
  • Fits the wide 8-inch by 7 1/8-inch blade footprint used across the 696N family

Small Things To Prep For

  • Fit can run tight against the housing before the unit seats fully
  • Sharp sheet-metal edges — handling gloves are worth keeping nearby
  • 50 CFM is modest airflow for a large bathroom with a big shower

Who this suits: a Nutone 696N or Broan box in a bathroom that sits near a bedroom, where a hum at night is the problem you are solving.

Who should pass: anyone whose priority is pulling heavy steam from a wet room — the 70 CFM and 100 CFM options clear air faster.

Best Multi-Pack

4. 2 Pack Bathroom Fan Motor Replacement for Nu-Tone B-roan Exhaust Fan Motor (SM550)

Two Motors Per KitUniversal SM550 Fit

Two 50 CFM SM550 motors per kit, for a home with two fans to replace.

Own a home with three bathrooms and two grinding fans? This is the arithmetic that matters — two SM550 motors in a single kit instead of buying the same part twice. Each motor runs on 120 volts at 60 Hz, moves 50 CFM, draws 34.8 watts at 0.29 amps, and spins at 3000 rpm. The kit pairs each motor with a 4 1/2-inch flat paddle blade, a shaft measuring roughly 3/16 inch by 1 3/4 inches, and a 6-inch wire ending in a two-prong plug.

The word “universal” is doing real work here. These motors replace the 65100, C65878, VFM100, E498-1, 82423K, K111, EM550, and EM750 numbers, and the design is made to fit Nu-tone, B-roan, Uppco, Bay Motors, Sears 569, and Dayton units. If your fan motor is a standard 3/16-inch shaft with a two-prong plug, chances are good this drops straight on the existing bracket.

The thing to understand is that a quiet motor and a strong blower are not always the same purchase, and this is a quiet one. Buyers rave about how silent it runs, but as one 4-star review noted, that quietness can leave you wondering whether it pulls as hard as the old motor did. If your bathroom clears fine and you want peace, this is the right kit. If your ceiling drips after every shower, look at the 70 CFM and 100 CFM options instead. And measure your fan blade diameter and total length before ordering — a wrong-size motor is the single most common misstep here.

The value equation: one purchase covers two fans, and the kit stacks a quality motor, blade, and plug in each box, so there is no second order to place.

The quietness trade: a whisper-quiet motor can feel weaker than the one it replaced, so judge it on whether your bathroom actually clears rather than on how it sounds.

Made for: a multi-bathroom home where two standard 3/16-inch-shaft fans are both on the way out.

Better skip if: your fan has a non-standard mount or you need maximum steam clearing — a matched single motor clears air harder.

Best For Fan-Light Combos

5. S0503B000 Bathroom Fan Motor 50 CFM 9×9 Inch, Fits 763RL 769RLA Exhaust Fan

9×9 Inch Housing FitPure Copper Motor

A 770 rpm, 2.0-sone motor sized for 9×9 fan-light combos like the 763RL and 769RL.

The number that defines this one is 770 rpm. That is the slowest spin on this list, and for a 9×9-inch fan-light combo it is exactly the point — a slower blower at 2.0 sones means you forget the fan is running. It is a 50 CFM motor at 120 volts, built from pure copper, and made to slot into the 9×9 housings used by the Nutone 763RL, 763RLL, 763RLN, 769RL, and 769RL/RF fan series.

What makes the swap easy is the access path. With a fan-light unit you remove the bulb, lift out the heat shield, drop the vent housing, unplug the two connectors, and back out a single screw — the motor then lifts free with the cage attached. Owners commonly finish it in about ten minutes. The unit comes with a three-year warranty, and the motor is the updated pure-copper design rather than an older aluminum version.

The one honest wrinkle is that noise is not unanimous. Some of these run so quietly you forget they are on; a few find more rumble than they expected. That variation usually depends on whether the new motor is seated firmly and the housing screws are snug — a loose mount is the most common cause of a noisy replacement. Tighten everything down and it settles.

The standout spec: 770 rpm at 2.0 sones is the quietest, gentlest spin here — ideal when the fan shares the ceiling with a light fixture and runs often.

Worth flagging: 50 CFM suits a standard bathroom but will feel slow in a large or very steamy one.

Pick this if: you have a 9×9 Nutone 763RL or 769RL fan-light combo and want a quiet swap with a fresh motor.

Think twice if: the room is large and steam clears slowly — a higher-CFM motor will move the air faster.

Genuine OEM Kit

6. Broan-NuTone RE70BN 70 CFM Bathroom Exhaust Fan Replacement Motor Kit

Genuine Broan-NuTone Parts70 CFM Upgrade

Genuine Broan-NuTone parts that take select 50 CFM fans to 70 CFM at 6.0 sones.

Buying factory parts is the appeal here: this is a genuine Broan-NuTone motor built to their own fit, so there is no question whether a third-party motor will line up. It delivers 70 CFM and spins at 3000 rpm, and the maker says it adds up to 40% more power for select 50 CFM fans in their lineup. The kit includes the motor, a blower wheel, two motor mounting plates, and the hardware — everything but the housing and the grille.

The upgrade path is deliberate. It fits a stack of Broan models including the 670, 671, 688, 689, EC50, EC70, ECH600, E050, and E070, plus NuTone units 693, 695, 696N, 695C, 695CB, 696NC, 690AC, 696N0, and 6950. It also covers Nautilus N671 and N688 and several Aira VSBP50M and VSBX50M models. One catch on fit: it does not fit 8-inch by 8 1/4-inch housings. The install needs no wiring and no drywall work.

The trade-off is loud and it is the single most-discussed point here. At 6.0 sones this is the noisiest option on this list, and the maker’s pitch for small bathrooms generally fails when the room is genuinely tight — 6.0 sones in a small bathroom is startling. If your old fan was a 2.0-sone or 3.0-sone unit, this will be a step up in sound. The reason to choose it anyway is the parts guarantee and the extra airflow, especially on older Broan 688-K and 695P “B” units that are hard to source anything for.

Why It Earns A Slot

  • Genuine Broan-NuTone parts, so the fit is guaranteed to the models listed
  • Jumps select 50 CFM fans up to 70 CFM for better steam clearing
  • Includes motor, blower wheel, two motor plates, and hardware in the box
  • No wiring and no drywall cutting — a motor-and-plate swap

The Honest Downside

  • 6.0 sones is the loudest motor here — a clear compromise if quiet matters
  • Does not fit the 8-inch by 8 1/4-inch housings listed in the spec sheet
  • Motor plate edges are sharp, so mind your hands during install

Best for: hard-to-source older OEM fans where genuine parts beat a universal fit, and a little extra airflow is welcome.

Not for: anyone chasing a quiet swap — the noise floor is the price of the extra push.

Most Airflow

7. Upgrade 8664RP 8663RP for Nutone 8664RP/8663RP B Unit Bathroom Fan Motor, 100CFM

100 CFM3.5 Sones

The 100 CFM motor for large bathrooms and 8663RP/8664RP B-unit housings.

When you need real pull, this is the one — 100 CFM, comfortably above the 70 CFM S89850000 and the 50 CFM options here, and enough to clear a large bathroom with a full shower fast. It runs at 1480 rpm on a 120-volt supply drawing 0.19 amps, puts out 3.5 sones, and is built around a pure copper motor with a 3-pin power connector.

The replacement list is deep: Nutone 8664RP, 8663RP, 8663P, 8673RP, 8673DG, 8673LG, 8673NP, 8673P, 8814R, 763RL, 769RL, 750, 751, 752, 6445RP, 671, 672, and more, plus part numbers S97017703 through S97017709 and 86933000. The kit includes the replacement motor, grounding clip, fan wheel, and a motor isolation block, so the whole assembly refreshes at once. It comes with a three-year service agreement.

The fit detail that matters is the locking nut: it secures the fan cage to the spindle so it cannot shift, which is a known failure point on some OEM versions. Installation takes about ten minutes with basic skills — watch a video, wear gloves, and test the fan before you close the housing back up. One small note from real buyers: the power cord runs long, so keep a couple of zip ties on hand to tidy it up.

what separates it: 100 CFM (cubic feet per minute — how much air it moves) is the strongest airflow number on this page, and the motor isolation block helps keep vibration down despite the high output.

One thing to plan for: at 3.5 sones it is louder than a quiet-bath pick — the trade for that much air movement.

This fits you if: your fan housing is 9×9 or one of the 8663RP/8664RP B-unit models and you need maximum airflow without a new fan.

Not your pick if: the motor is the easy part and what you really want is silence — 3.5 sones is a working fan, not a quiet one.

Best 90 CFM Fit

8. 【Upgrade】 Model 671 Fan Compatible with Nutone 671rb, 672r, Broan 750, 751, 752, N750

90 CFM At 3.5 Sones3-Pin Connector

A 90 CFM, 3.5-sone motor for Nutone 671/672 and Broan 750-series fans.

This motor moves 90 CFM at 3.5 sones, drawing 33W and spinning at 3000 rpm on a 60 Hz supply with a 3-pin connector. That sits between the 70 CFM top pick and the 100 CFM airflow leader — a strong middle ground for a standard full bathroom. It fits the Nutone 671, 671R, 671RB, 672, 672R, and 672RB units, and lines up with Broan 750, 751, 752, and N750 series fans.

The upgrade runs on a pure copper motor with better conductivity and heat dissipation than the older aluminum-plated design, and Motoasis backs it with a three-year manufacturer defect replacement service. Owners mention a fit that mirrors the original — many describe the motor and construction as a match for OEM quality once it is seated, and the sound stays low even as the fan spins up. Typical install time runs about ten to fifteen minutes.

The one limitation baked into the design is that it is a 90 CFM, 3.5-sone motor — not a whisper model, and not the airflow leader either. It does not fit a Broan 671, only the Nutone 671 series, so check which side of that split your fan falls on. If it lines up with your part number, it slots in cleanly and quietly.

What Wins People Over

  • 90 CFM splits the difference between the 70 CFM pick and the 100 CFM leader
  • Pure copper motor rated well above the older aluminum design for conductivity
  • 3.5 sones keeps it comfortable while still pulling serious air
  • First-time fit matches the original housing on 671/672 and 750-series fans

Worth Knowing First

  • Does not fit the Broan 671 — only the Nutone 671 series
  • 3.5 sones is audible; it is not a quiet-bath pick
  • 90 CFM means a long fast swap is needed before closing the housing

The right call for: a Nutone 671 or Broan 750-series fan where you want strong-but-not-loud airflow with a clean drop-in fit.

Look past it if: your fan is a Broan 671 (not Nutone) or you want the quietest possible motor — the 2.0-sone options suit better.

Built To Last

9. Endurance Pro 3.3 Inch Diameter Vent Fan Motor Direct Replacement for Nutone/Broan 40933, 86933, 8693000, JA2B104N

UL/CSA ApprovedTwo-Year Warranty

A drop-in replacement engineered to outlast the fan you pulled it from.

This is the motor for a stalled hunt — the one you buy when nothing else has matched your part number. It replaces the Nutone 86933, 86933-000, 8693000, and 86933000 numbers, plus Package 40933, JA2B104N, and Century JA2B104N. Specifications: 1550 rpm, 120 volts, 60 Hz, 1.2 amps, and 0.2 horsepower. It uses a 1/4-inch-diameter shaft measuring 1 1/4 inches long, a two-prong plug, and CCWSE rotation as determined from the shaft end.

The name of the game here is durability engineering: sleeve bearings, a shaded-pole design, an open enclosure, automatic overload protection, and single-phase construction. It is UL and CSA approved to assure safe operation, and SupplyEdge backs it with a two-year, no-questions-asked warranty. Owners who install it into genuinely old fans — including a 60-year-old bathroom fan — report it running perfectly as a straight swap.

Be ready for two small mechanical adjustments on some vintage installs. The power cord’s straight plug may need to be rewired to a right-angle end for the grille to seat, and on some units the mounting bolts must be reversed to exit the rear. One owner found the plug too long to reinstall the grille without modifying it, so keep a wire cutter handy and re-use the old plug if needed. Plan for those and the motor drops in exactly.

Why it belongs here: the 1.2-amp shaded-pole motor with automatic overload protection is the reason this thing survives continuous bathroom duty — the 1550 rpm speed suits the older fans it replaces.

The install caveat: expect to trim or swap the plug on tighter grilles and to reverse the mounting bolts on vintage rear-exit brackets — a small teardown, not a defect.

Perfect for: vintage Nutone or Broan fans whose original motor carries the 40933 or 86933 number and nothing modern matches.

Look elsewhere if: you want a plug-and-play kit with a pre-formatted bracket — the universal and model-specific kits above are simpler for those.

Understanding the Specs

Airflow And CFM

CFM stands for cubic feet per minute — the volume of air the blower pushes out of the bathroom in a single minute. It is the number that decides whether your mirror clears after a shower. A small half bath runs fine on the 50 CFM models; a full bath with a shower wants more, and the 70 CFM and 100 CFM options here move air noticeably faster. The catch is that your vent pipe has to be able to carry that air away — pushing more air than the pipe can handle just makes noise without clearing the room any better.

Sones, RPM, And The Power Feed

A sone measures how loud the fan sounds to your ear, where roughly one sone is the hum of a quiet refrigerator and each added sone is a clear jump in volume. A motor rated 2.0 sones is one you will stop noticing; a 6.0-sone unit will make you reach for the switch every time. RPM is how fast the shaft turns — higher speeds tend to move more air but often louder. And every motor here runs on standard 120-volt, 60 Hz household current, which is what the wiring already in your ceiling provides.

FAQ

How do I know which replacement motor fits my existing bathroom fan?
Read the part number stamped on the motor you are replacing, then match it against the compatibility list on the product page. The top pick here, for example, replaces 89850000 and 89321000 and fits a long spread of Nutone 665, 668, and 9965 models. If your number is on the list, the shaft, plug, and mounting plate almost certainly line up. If it is not listed, do not guess — measure your shaft diameter and length, and note your plug style.
Will a 70 CFM or 100 CFM motor be too loud for a small bathroom?
It can be. Airflow and noise rise together in most fans, and the Broan-NuTone RE70BN runs at 6.0 sones, which buyers describe as startling in a small room. If quiet matters more than raw air movement, the 2.0-sone options like the C350BN move less air but are far easier to live with. Match the CFM to the room: 50 CFM is typically enough for a half bath, while the 70 CFM and 100 CFM motors suit larger bathrooms with a shower.
Do I need to remove the whole fan from the ceiling to swap the motor?
No, and that is the main reason this repair is worth doing. Most of these motors are designed to be reached from below — you pull the grille, unplug the existing motor, back out the mounting screw or bracket, and slide the new motor into the housing that is already in the ceiling. Several units here are reported as roughly a ten-minute job. A few vintage installs need small adjustments, but pulling the whole housing down is rarely required.
What is the difference between a C-frame motor and a cylinder-type motor?
A C-frame motor is a flat, open-sided design common in older bathroom fans, and many of the motors here are built in that style. A cylinder-type motor is enclosed in a rounded tube and often drops into the same space on the same bracket despite the shape difference. When swapping between the two styles, the mounting plate is what usually has to match — several kits include multiple motor plates for exactly that reason. Always compare overall length and shaft position, not just the shape.
Can I replace a 50 CFM motor with a 70 CFM or 90 CFM motor?
Often yes, and the Broan-NuTone RE70BN is explicitly built to upgrade select 50 CFM fans to 70 CFM, while the 671-series motor steps up to 90 CFM. That said, more airflow only helps if your vent duct is sized to carry it. If your existing duct is narrow or has a long run, a more powerful motor may just run louder without clearing the room much faster. Check the duct and the housing before you size up.
How long should a replacement bathroom fan motor last?
There is no single answer, because running time, humidity, and bearing quality all factor in. What the data does show is a split in owner experience. Several motors here are praised for still going strong after years — including one described as fine after a year and a half — while durability is flagged as a concern on others where a motor failed within a couple of years. Choosing a motor with sleeve bearings, overload protection, and a solid warranty is your best hedge. The Endurance Pro here carries a two-year warranty, and several others offer three-year coverage.
Do I need new wiring or an electrician to install these motors?
No new wiring is needed for most of these swaps, because they plug into the receptacle already inside your fan housing. The connectors here are either two-prong plugs or three-pin connectors, so match the plug typeto your old motor before ordering. Always turn the power off at the breaker before you touch anything. The Broan-NuTone RE70BN, for instance, is specifically described as requiring no wiring and no drywall cutting or repair, and several other kits here call out the same.
Why is my new fan motor noisier than the one it replaced?
Usually one of three things. First, the new motor may simply run at a higher sone rating — the 6.0-sone RE70BN is noticeably louder than a 2.0-sone unit. Second, the motor may not be seated firmly, or the housing screws may be loose, which turns a quiet motor into a rattler. Third, the fan cage may be shifting on the spindle — the 8664RP motor here addresses that directly with a locking nut that secures the cage so it cannot move. Check firm mounting and cage seating first; a snug install is the fix most of the time.
Is it worth replacing just the motor instead of the whole fan?
In most cases yes, and the reason is simple: the motor is the part that wears out, while the housing, duct, and grille usually still have years left in them. Replacing just the motor skips the ceiling work, the drywall repair, and the hassle of pulling the whole unit down. The only exceptions are when the housing itself is cracked or rusted out, or when your fan sits in a non-standard box size that makes sourcing parts harder — in those cases a new fan may make more sense.
What tools do I need to swap a bathroom fan motor?
A screwdriver for the motor bracket screws and the grille, and that is the core of it. A pair of handling gloves is worth having, because several kits here have sharp sheet-metal edges — the RE70BN and the C350BN both flag sharp edges during install. On some vintage fans you may need wire cutters or a small steel mending plate to adapt the bracket. Keep a flashlight handy, since the inside of a fan housing does not get much light.

Final Thoughts: The Verdict

For most households, the winner here is the 89850000 S89850000 Bathroom Exhaust Fan Replacement Motor & Blower Wheel because it moves 70 CFM at 3000 rpm, ships with a fresh blower wheel, and slots into a ceiling you never have to take down. If quiet is your priority, grab the C350BN B Unit 50CFM Fan at 2.0 sones. For a bathroom that never seems to clear, the 8664RP 8663RP Nutone Motor at 100 CFM is the one to reach for. Whichever you pick, match the part number on your old motor first — that single check is what turns this into a ten-minute fix instead of a second trip to the store.

How We Picked

We do not accept paid placement. Every pick is matched to a real buyer and a real use-case; we do not hands-on test units.

Sources & Methodology

Specifications: manufacturer listings and product documentation. Review insights: verified customer reviews, as of September 2026. Pricing: not shown on this page (it changes often); check the current price via the retailer link.

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Mo Maruf

Mo Maruf

Founder

I am a dedicated home cook and appliance enthusiast. I spend hours in my kitchen testing real-world storage methods, reheating techniques, and kitchen gear performance. My goal is to provide you with safe, tested advice to help you run a more efficient kitchen.