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.
A bathroom exhaust fan that sounds like a jet engine or just hums without moving air isn’t a sign you need a whole new unit. More often than not, the motor and blower wheel inside are the only parts that have worn out, and a replacement kit brings the whole assembly back to life in about ten minutes with nothing but a screwdriver. This guide sorts through the best of those kits so you can match one to your old fan’s housing and get your bathroom venting properly again.
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.
Here’s how to find the right bathroom exhaust fan replacement kit for your setup without guessing at measurements or risking a messy return.
Our Picks at a Glance
How To Choose The Best Bathroom Exhaust Fan Replacement Kit
The most important thing to know is that the brand of your old fan matters less than the physical dimensions of the motor and blade inside it. These kits are designed to work across many models, so you need to match the mounting hole spacing, the blade diameter, and the shaft length to what you pull out of the ceiling.
Measure Your Old Motor Before You Buy
Pull the fan assembly down and measure the distance between the two mounting bolts on the bracket, the diameter of the fan blade, and the length of the motor shaft. A kit whose mounting studs are only a fraction of an inch off can still be made to work, but you’ll save yourself frustration if you get a close match on paper first.
Match the Rotation Direction
Motors are labeled either CW (clockwise) or CCW (counter-clockwise) depending on which way they spin when viewed from the shaft end. If you install a motor that spins the wrong way, it will push air down into the room instead of up the vent pipe. Most kits make this direction clear in the description, so check it against your old unit.
Consider the CFM and Sone Ratings
CFM stands for cubic feet per minute, and it measures how much air the fan moves. A higher number means better ventilation, but it almost always brings more noise, measured in sones. If you’re replacing a 50 CFM unit, a 70 CFM upgrade is tempting, but you have to decide if the extra whoosh is worth it in a small bathroom.
Quick Comparison
| Model | Best For | Voltage / Amps | Speed | Blade Size | Amazon |
|---|---|---|---|---|---|
| S97012038 Kit★ Best Overall | Exact-fit Broan swaps | 120V / 0.29A | 3000 rpm | 4.5 inch | Amazon |
| Frienda UniversalBest Value | Vintage 686/687 housings | 120V / 0.6A | 3000 rpm | 6.6 inch | Amazon |
| BOJACK 0.60ATop Performer | High-speed 686/687 swaps | 120V / 0.60A | 3500 rpm | 6.6 inch | Amazon |
| BOJACK 1A | Older Nutone/Broan swaps | 120V / 1A | 3000 rpm | 4 5/8 inch | Amazon |
| PANDEELS SM550 2-Pack | Budget two-bathroom fix | 120V / 0.29A | 3000 rpm | 4 1/2 inch | Amazon |
| Motoasis C350BN B Unit | Nutone 696N/695 B units | 120V / N/A | 1450 rpm | 8 x 7 1/8 inch | Amazon |
| Fetechmate 99080166 2-Pack | High-airflow 70 CFM swaps | 120V / 1.4A | 3000 rpm | 7/32 x 1-1/4 inch shaft | Amazon |
| Broan-NuTone RE70BN | Genuine 70 CFM upgrade | 120V / N/A | 3000 rpm | N/A | Amazon |
| Cylrod 8664RP B Unit | Quiet 100 CFM swaps | 120V / 0.19A | 1460 rpm | 9 x 9 inch frame | Amazon |
In‑Depth Reviews
1. S97012038 Bathroom Vent Exhaust Fan Motor Replacement Kit
Our pick — over 4.5★ from 150+ verified ratings; the strongest balance of quality and price.
The direct-drop-in swap that silences the scream without touching your housing.
This kit is the single most reliable way to revive a Broan fan because it replaces the exact motor assembly the original used. The motor runs at 3000 rpm on 120 volts pulling just 0.29 amps, and it comes with a 4.5-inch blower wheel already attached, so the whole unit bolts in as one piece. The plug wires are 6.37 inches long with a 2-claw plug, which matched the original wiring setup for most owners.
The buyer consensus here is loud and clear: this is the easy one. The installation process is just two bolts — you remove the old motor bracket, thread the bolts through the new motor’s holes, and tighten. Buyers report it as an “Exact swap for the original. Easy install only took a few minutes. Just a quiet and same airflow as the original.” That quiet operation is the standout, with people noting their bathroom “no longer sounds like a Banshee” after the swap.
It’s built for the common Broan 50 CFM line, fitting models 659, 662, 663, 668, 678, and 688, among others. If your ceiling box is one of those, the 1.73-inch center mounting bolt spacing should line right up. The trade-off is that it’s a specific fit — if your old fan isn’t a Broan, this isn’t the universal option.
Why owners love it
- Blade and motor arrive pre-assembled for a true one-piece swap
- Barely whispers compared to the old jet-engine hum
- Replacement quality is excellent — buyers buy a second one for other bathrooms
Who should think twice
- Only fits Broan-style housings, not universal across brands
- Some buyers found the shaft size required careful alignment with the old bracket
This is your pick if: you have a Broan 659–688 series fan and want the lowest-effort, highest-match fix.
Look elsewhere if: you need a motor for a non-Broan housing or a larger blade than 4.5 inches.
2. Frienda Universal Bathroom Vent Fan Motor Replacement Kit
A big 6.6-inch paddle blade that breathes new life into old Nutone boxes.
Revive an older Nutone or Broan fan housing (models like the 686, M686, 687, or 8870) without replacing the whole unit — this universal motor kit is the budget-friendly fix. It spins at 3000 rpm on a 120-volt, 0.6-amp draw, and the standout feature is the 6.6-inch plastic fan blade, which is larger than the compact blades on other kits, so it moves more air through a wide housing.
Owners keep coming back to this one for vintage installations, especially “its compatibility with vintage Aubrey models” — the sort of fan that a whole-new unit would never fit without cutting drywall. The universal motor and fan saved the old housing, and the install is a 10-minute job with a near-exact match to the original. One reviewer noted the spin is fast and the noise is moderate but quieter than the dying old motor it replaced.
The catch: the shaft fit is tight, and there are no instructions for attaching the fragile plastic blades. Buyers had to consult external videos to figure out the seating. It’s a small hurdle on an otherwise excellent budget pick, and it explains why this one earns its place as a value choice rather than the top spot.
Best for vintage boxes: If you have an old wide Nutone housing, this 1.5-pound motor with its 6.6-inch blade is the cheapest way to save it from the dumpster.
The one hurdle: Blade installation needs care and a video walkthrough — the tight shaft doesn’t forgive rushing.
Reach for this if: you’re repairing a classic 686/687-series housing and don’t want to tear out drywall for a new fan.
Consider the alternative if: you’d rather not fuss with delicate blade alignment or you need a smaller, more universal diameter.
3. BOJACK Bathroom Vent Fan Motor 120V 60Hz 0.60A 30W
The fastest-spinning 686-series swap, pushing 3500 rpm for serious air movement.
This BOJACK motor turns 500 rpm faster than the Frienda kit above — 3500 rpm versus 3000 rpm — on the same 6.6-inch flat paddle blade. That extra speed translates to noticeably stronger suction for a 686, 687, 8870, or M686 housing. It draws 0.60 amps at 120 volts, and the 1.7-pound metal construction feels substantially more solid than plastic competitors.
UL/CSA certification confirms independent safety testing that budget kits often skip. Owners mention it’s “well made and strong air movement,” with several noting it replaced much older, higher-draw motors (one swapped out a 2.3-amp unit from a 40-year-old Miami-Carey fan) and fit the original bracket without modification.
There’s a real trade-off with that power: noise. The honest take from the reviews is that it’s louder than a whisper — one buyer called it “a jet engine” — and the blades run wider than some vent pipes, occasionally needing a trim. If your old fan was already noisy, you’ll likely find this an improvement; if you worship silence, the lower-RPM picks are safer.
The power payoff
- Faster spin than standard kits means better moisture pull
- Metal body and blower wheel feel built to last
- Safely certified, adding confidence for a motor near moisture
The honest cost
- Measurably louder than lower-RPM motor kits
- Wide paddle blade may need trimming to fit narrow vent pipes
Grab it if: airflow is your priority and your housing can take a 6.6-inch blade.
skip it if: you need near-silent operation or a blade that slots into a tight pipe without modification.
4. BOJACK Bathroom Vent Fan Motor 120V 60Hz 1A
The workhorse for mid-century Nutone and Broan fans, with bolts that line right up.
This BOJACK is the one to reach for when your old fan dates back to the 1970s or 80s. It’s a 1-amp, 50 CFM motor spinning at 3000 rpm, and the 4 5/8-inch blade with a 3/16 x 1.5-inch splined shaft replaces the classic Nutone Broan motors (models 662, 688, and many more).
Customers note “perfect replacement” results for decades-old units — one owner revived a fan from 1976, another a 39-year-old Nutone 57N2, and the screws “line up perfect with mount for an easy install.” UL certification matches the safety standard of its BOJACK sibling. The plug-in design works from the start, though older wired models sometimes need the mounting bolts reversed to fit the bracket.
Airflow gets solid marks, but a few owners note it doesn’t move quite as much air as the old 1-amp original did, and the noise level is moderate rather than hushed.
Built for old wiring: A 1-amp draw matches the original motors in 1970s and 80s Nutone fans, so it won’t trip older circuits.
The check before buying: Some owners had to reverse the two mounting bolts to fit their bracket — a 2-minute tweak, not a dealbreaker.
Your best bet if: you have a pre-1990 Nutone or Broan fan with a 4 5/8-inch blade and want a bolt-in match.
Not the pick if: you want a quieter motor than the original or need a larger 6-inch+ blade for a wide housing.
5. PANDEELS SM550 Bathroom Fan Motor Replacement (2 Pack)
Two quiet SM550 motors for the price of one — a landlord’s and homeowner’s two-bathroom special.
If you have two bathrooms with failing fans, this PANDEELS two-pack is the most efficient way to fix both at once. Each SM550 motor runs at 3000 rpm on 120 volts at just 0.29 amps, and the kit includes a 4 1/2-inch flat paddle blade per motor, with a 3/16 x 1 3/4-inch shaft. The universal design targets the common SM550 line, covering Nu-tone, Broan, Uppco, Bay Motors, Sears 569, and Dayton.
The near 5-star consensus highlights how quiet this swap is — reviewers point out it’s “much quieter than the old fan” and that it fits old NuTone housings perfectly, even a 40-year-old one. The install is famously fast, with many finishing in under 10 minutes using the included guidelines. It’s a “heavyweight and durable” motor that runs without overheating, which matters if your fan is on a timer.
The main caveat is the universal label: some buyers found their specific fan blew the wrong direction (counter-clockwise instead of clockwise) and needed to rewire the plug to flip it. It’s not a universal-fit guarantee across every oddball housing, but for the common SM550 footprint, it’s a phenomenal deal.
Why it’s a steal
- Two complete motor-and-blade kits in one box
- One of the quietest motors in this lineup
- Easy 10-minute install for most standard housings
What to double-check
- Direction of spin may need a plug reversal on some fans
- “Universal” has limits — it won’t fit every brand’s bracket
Ideal for: anyone with multiple SM550-compatible fans to fix without breaking the budget.
Consider elsewhere: if you need a guaranteed CW (clockwise) spin without fiddling with wires.
6. Motoasis C350BN B Unit 50CFM Fan
The B-unit replacement that adds a 3-year warranty and a whisper-quiet 2.0 sone rating.
This Motoasis kit is for the specific “B unit” fans — the Nutone 696N (695) and the C-350/370 series — that use an 8 x 7 1/8-inch blade. It’s a full assembly swap rated at 50 CFM with a remarkably quiet 2.0 sone noise level (sones measure loudness, and lower is quieter). The pure copper motor is built for longer life than the aluminum-plated originals.
The 3-year manufacturer defect replacement warranty outlasts cheaper kits. Buyers confirm the fit is “perfect” in the Broan/Nutone box, with simple clip, screw, and unplug steps that take about 10 minutes. The sound level is consistently called lower than the original, making it a nice improvement rather than just a repair.
The only honest friction point is the blade fit — it’s tight, and the package warns to watch for sharp edges during install. A few owners found it slightly noisier than their old unit rather than quieter, so the 2.0 sone rating is a guideline, not a guarantee.
Worth the premium for: the 3-year service guarantee that no other kit in this list matches.
The trade-off: a tight blade fit and sharp edges demand careful handling during the swap.
Pick this if: you have a Nutone B-unit fan and want a manufacturer-backed, quieter upgrade.
Look past it if: you don’t need the warranty or your fan uses a different blade size entirely.
7. Fetechmate 99080166 BP28 Bathroom Fan Motor (2 Pack)
A twin-pack of 70 CFM motors that yanks steam out fast, ideal for larger baths.
When your bathroom is big enough that 50 CFM just doesn’t cut it, this Fetechmate kit is the upgrade. It’s a 70 CFM motor pulling 1.4 amps at 3000 rpm, and the package includes two complete motors with blower wheels. The design fits the classic Broan and Nu-tone line — models 671, 671a, N678, N655, N679, and more.
Performance wins owners over. The 70 CFM rating (cubic feet per minute, or how much air it moves) “quickly removes warm, moist air from the bathroom,” according to reviews. Install is simpler than replacing a whole unit — several note it “bolts right in without modifications.” One buyer who replaced an inaccessible attic fan found it “much quieter than the old jet-engine fan,” even at this higher airflow.
The noise is the honest catch: at 70 CFM, it’s fundamentally louder than a 50 CFM unit. One owner called it “far more noisy than the 50” while confirming it works well. A couple of reports mention a rubbing noise developing after a few weeks, traceable to loose motor tape — worth a quick check during install.
Performance first
- Two 70 CFM motors for a high-volume ventilation solution
- Strong suction that clears steam in minutes
- Generally quieter than the old high-output fans it replaces
Volume has a voice
- 70 CFM runs noticeably louder than 50 CFM kits
- Minor mechanical noises can appear if internal tape shifts
Choose this for: a large or humid bathroom where 50 CFM has always felt weak.
Decide against it if: you prioritize a silent fan and your room is small enough for a lower-CFM motor.
8. Broan-NuTone RE70BN 70 CFM Replacement Motor Kit
The genuine Broan-NuTone fix that fits a huge range of 50 and 70 CFM models.
This is the one kit where you don’t have to trust a third-party aftermarket brand — it’s the genuine Broan-NuTone part. The RE70BN is a 70 CFM replacement motor designed for select Broan-NuTone 70 CFM fans, and it can even deliver up to 40% more power when used in a 50 CFM fan. The 2.4-pound kit includes the motor, blower wheel, two motor mounting plates, and all hardware.
Fit is the name of the game here. It’s compatible with a wide range of Broan (670, 671, 688, EC50, ECF50), NuTone (693, 695, 696N), and Nautilus (N671, N688) models — though it explicitly does not fit 8″ x 8-1/4″ housings. Buyers praise it as a “perfect match” for their 1990s units, with a simple unplug-and-replace install that takes under 20 minutes.
The honest downside is loud and unavoidable: the noise level is rated at 6.0 sones, which is noticeably louder than the 2.0 sone Motoasis pick above. Several buyers describe it as “pretty loud,” with one calling it “too loud” after six months. Some appreciate it as white noise in an office; others find it grating in a bathroom. If you can handle the volume, the genuine-brand fit and 70 CFM airflow are excellent.
The safest OEM choice: Genuine Broan-NuTone parts guarantee the fit on a wider range of models than any aftermarket kit.
The known cost: 6.0 sones is the loudest rating in this entire roundup — you’re trading peace for guaranteed compatibility.
Best for: owners who want an OEM-matched motor and value guaranteed fit over whisper-quiet operation.
Not for: anyone who hates fan noise — this one sings at 6.0 sones.
9. Cylrod 8664RP B Unit Bathroom Fan Motor
100 CFM of airflow at just 3.5 sones — the rare quiet high-volume upgrade.
If you want the highest airflow in this lineup without the roar, the Cylrod 8664RP delivers. It’s a 100 CFM motor assembly — the most powerful here — yet its noise rating of 3.5 sones sits comfortably below the loudest picks. The secret is the slower spin: 1460 rpm at just 0.19 amps, moving the same volume through a larger, more efficient blade design.
This kit targets the Nutone 8664RP B-unit and its extended family (8663RP, 8673RP, 6445RP, 671R, 672R, 763RL, 769RL, 750, and more). It includes the replacement motor, fan wheel, grounding clip, and motor isolation block. Owners with 26-year-old Nutone units report it’s an exact replacement that fixes the annoying impeller sliding issue and runs as quiet as the original. The 3-year service promise matches the Motoasis warranty.
The one notable quirk is the power cord — it’s long, so buyers advise keeping zip ties handy for cable management. And it’s specific to the 8664RP-style B units, so it won’t help if you have a generic 688 housing. For the right fan, this is the best of both worlds: power and quiet.
The dual threat
- Highest airflow at 100 CFM without sacrificing quiet operation
- 3-year after-sales service covers repair or replacement.
- Fixes common impeller sliding and rubbing issues on old units
Before you commit
- Fits only 8664RP-style B units — not a universal swap
- Long power cord needs zip ties for tidy installation
Grab it if: you have an 8664RP-family B unit and want maximum ventilation with minimal noise.
Pass if: your fan housing is a different size or you need a simpler universal motor.
Understanding the Specs
Amps (A) and Voltage (V)
Amps measure the electrical current the motor draws, and volts measure the electrical pressure feeding it. Virtually all bathroom fans run on standard 120-volt household current. A motor drawing 0.29 amps uses less power than one drawing 1.4 amps, which matters when you’re replacing a motor in an older home with wiring that’s less sturdy.
RPM and CFM
RPM (revolutions per minute) is how fast the motor shaft spins, while CFM (cubic feet per minute) measures the actual volume of air moved. They’re related but not identical — a larger blade spinning slowly can move as much air as a small blade spinning fast. That’s why the 1460 rpm Cylrod quietly moves 100 CFM.
Sones (Loudness)
Sones are the unit for perceived loudness. Lower is quieter: 1.0 sone is a quiet refrigerator hum, 2.0 is a tranquil office, and 6.0 is noticeably loud. When a higher-CFM motor also has a high sone rating, you’re trading peace for performance.
Rotation Direction (CW vs CCW)
Motors spin either clockwise (CW) or counter-clockwise (CCW) when viewed from the shaft. The direction determines which way air blows. Installing the wrong spin direction means your “exhaust” fan will push air down into the room instead of out the vent — an easy mistake that ruins the install.
FAQ
How do I know which replacement kit fits my bathroom fan?
What does CFM mean and how much do I need?
What is a sone rating?
Do I need to replace the whole bathroom fan or just the motor?
What is the difference between 50 CFM and 70 CFM replacement motors?
What does CCW mean on a fan motor?
Will a 2-prong plug motor work if my fan is hardwired?
Is it safe to install a bathroom fan motor myself?
How long should a replacement bathroom fan motor last?
What if the new motor spins the wrong direction?
Final Thoughts: The Verdict
The bathroom exhaust fan replacement kit that wins for most people is the S97012038 Kit because it’s a true bolt-in swap for the most common Broan fans — fast, quiet, and dependable. If you’re on a tight budget and fixing multiple bathrooms, the PANDEELS 2-Pack stretches your dollar the furthest. And when you need serious air movement for a big, steamy bathroom, the Cylrod 8664RP delivers 100 CFM without a jet-engine roar.
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 August 2026. Pricing: not shown on this page (it changes often); check the current price via the retailer link.
As an Amazon Associate, KitchPrep earns from qualifying purchases. This does not affect which products we feature.
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