A rattling bathroom fan can turn a quick shower into a longer cleanup, especially when the motor is slow, noisy, or no longer pulls air through the duct. The right repair starts with your housing label, not the motor’s appearance, because shaft size, rotation, mounting points, and blower-wheel dimensions all affect the fit.
Five options below are component-level repair parts, while the Fitop and Orsong choices are complete fans for a different installation path. This guide helps you sort those distinctions, compare supported dimensions, and avoid replacing a working housing with a mismatched assembly.
A Fast Comparison Of The Options
AMI PARTS SM550 50 CFM Motor
AMI PARTS S99080166 BP28 Motor
Hiorucet BP27 Motor for Broan-Nutone 663, 678, 688, 671, 659, 662, 668, 670, 689, 669, S97012038 Replacement
AMI PARTS YJF6178 Motor
BXKP S97017646 Motor and Blower Wheel for Broan-NuTone 605, 665, 668, 9965, 9905
Fitop 80 CFM 1.0 Sone Vent Fan
Orsong 10-Inch Exhaust Fan
Inside Each Recommended Option
Picture a bathroom fan that has slowed to a lazy wobble after years of daily use. The AMI PARTS SM550 targets legacy housings with a 50 CFM motor, and its reversible rotation gives you more latitude than a fixed-direction assembly when the original motor’s orientation is unclear.
Unlike the 70 CFM options later in this list, this motor includes a smaller 4.5-inch blower and works with a broad set of listed part numbers. That combination suits careful repairers working from an older housing label.
The Helpful Details
- Clockwise and counterclockwise rotation support more housing arrangements.
- A six-inch lead with a two-prong plug gives you room during reassembly.
- Listed dimensions support direct replacement of several common motor assemblies.
Things To Consider
- Confirm the 3/16-inch shaft, 1-7/8-inch stud spacing, and blower dimensions before ordering.
- The 50 CFM rating is lower than several 70 CFM alternatives, so housing airflow remains the deciding factor.
Key Specs
Made For Legacy Housing Repairs
You benefit most with an older Broan, Nutone, Uppco, or Ventorola housing whose label matches a listed part number and dimensions.
A Better Fit Elsewhere
The AMI PARTS S99080166 BP28 Motor better serves a compatible 70 CFM housing needing the larger 5.27-inch blower.
A failed motor does not always mean the whole bathroom fan needs to come down. This AMI PARTS assembly includes the S99080166 motor and a 5.27-inch blower wheel, giving you both rotating parts in one repair package.
Its compatibility list covers numerous NuTone and Broan housing numbers, but the fit still depends on more than the brand. The 7/32-inch splined shaft, 7/8-inch motor stack, and counterclockwise rotation need to agree with your housing.
Why It Works Well
- The matching motor and blower remove the need to source two repair components separately.
- A 70 CFM rating suits many medium-sized bathroom ventilation setups.
- The long model list gives you several recognized housing numbers to compare against the label.
Practical Considerations
- Counterclockwise rotation narrows the fit compared with a reversible motor.
- Older housings may carry several similar numbers, so check the complete list rather than the brand alone.
Feature Snapshot
Built With In Mind
You benefit most with a listed Broan or NuTone housing that uses the BP28-style 70 CFM assembly and a counterclockwise motor.
Where Another Pick Shines
The Hiorucet BP27 Motor suits compatible Broan-Nutone housings requiring the shorter 3/16-inch shaft and 4.625-inch blower.
Some older Broan-Nutone bathrooms carry a motor number on the housing that differs from the replacement part’s sales name. The Hiorucet BP27 package includes a motor and blower wheel, making it a practical option for housings listed under the 663, 678, 688, and related families.
Its 50 CFM rating sits below the 70 CFM AMI PARTS S99080166 BP28 Motor, so the housing specification takes priority. For a matching BP27 system, the smaller 4.625-inch blower and 3/16-inch shaft may be the more useful comparison points.
Strengths Worth Knowing
- Motor and blower wheel arrive together for a component-level repair.
- The listed model families cover many residential and commercial Broan-Nutone housings.
- A two-prong connection and housing-mounted design can simplify a like-for-like swap.
Trade-Offs To Consider
- Counterclockwise rotation must match the original motor’s direction.
- Its 50 CFM rating may not equal the airflow capacity of a 70 CFM replacement.
Right Fit For
You benefit most with a housing listed under the BP27 family or one of the stated Broan-Nutone model numbers.
Reach For A Different Pick When
The AMI PARTS SM550 50 CFM Motor better serves a compatible housing where reversible rotation is necessary.
A repair is less disruptive when the replacement reaches the existing wiring without stretching the lead into a tight bend. The AMI PARTS YJF6178 provides an 8.66-inch wire, which is the longest listed among these component options, along with a motor and a flat paddle-style blower.
It targets Nautilus and Broan housings associated with several 655, 657, 658, 671, and 679 numbers. The 70 CFM rating also places it closer to the S99080166 BP28 Motor than to the smaller 50 CFM assemblies.
Noteworthy Benefits
- The extended lead provides useful reach during reassembly.
- A 70 CFM motor supports the ventilation capacity of a medium-sized bathroom.
- The package contains both the motor and its 5.27-inch paddle blower.
Points To Keep In Mind
- Counterclockwise rotation and the 1.19-inch shaft must match the housing.
- The stated fan size varies slightly between the included blower and specification listing, so check your housing.
Quick Facts
Who Will Love This
You benefit most with a compatible Nautilus or Broan housing needing a 70 CFM counterclockwise motor and roomier wiring reach.
Another Choice May Suit
The BXKP S97017646 Motor and Blower Wheel better serves a Broan-NuTone housing listed for the S97017646 assembly.
Replacing only a motor can leave a tired blower wheel behind, which may keep a repaired fan sounding uneven. The BXKP S97017646 package pairs the motor and blower wheel as a single assembly, which is useful for a Broan-NuTone housing with a failed or slow motor.
The supported housing list centers on 605, 665, 668, 9965, and 9905 families. That narrower focus makes the model check more important than brand alone, and the preassembled design can reduce the number of parts you handle during the repair.
Benefits That Matter
- Motor and blower wheel are packaged together.
- Several Broan-NuTone housing families are covered by one replacement.
- The assembly approach avoids mixing an old wheel with a new motor.
Small Caveats
- Confirm the complete model number, including suffixes, against the compatibility list.
- You still need to verify the housing’s mounting arrangement before removal work begins.
Best Suited To
You benefit most with a listed 605, 665, 668, 9965, or 9905 housing that needs both rotating components replaced.
Swap It Out When
The AMI PARTS S99080166 BP28 Motor better serves a listed BP28 housing requiring its 7/32-inch splined shaft.
Sound matters most in a bathroom beside a bedroom or shared hallway, where a rattling fan becomes more noticeable than a hum. The Fitop is a complete ceiling fan rather than a repair motor, combining 80 CFM airflow with a stated 1.0 sone rating, a measure of perceived sound.
Its galvanized-steel housing, zinc-alloy and PC components, and integrated backdraft damper suit a fresh ceiling installation. The backdraft damper helps restrict outside air from returning through the duct when the fan is off.
Advantages To Know
- The 1.0 sone specification targets a comparatively quiet daily setup.
- 80 CFM provides higher rated airflow than the component motors listed here.
- The integrated damper reduces unwanted airflow from outside the room.
- A permanently lubricated 23W motor suits routine household ventilation.
Practical Considerations
- This complete fan requires a 7.3-by-7.6-inch ceiling opening.
- Its 4-inch duct connection must match your existing vent route.
Technical Highlights
Home Office Pick
You benefit most with a new ceiling installation that matches the housing opening, 4-inch duct, and quiet-operation preference.
Look Elsewhere When
The AMI PARTS SM550 50 CFM Motor better serves a repair that requires retaining an existing compatible housing.
A compact ceiling panel can simplify a renovation where a larger grille would crowd the available space. The Orsong option is a complete bathroom exhaust fan without a light, paired with a 10-inch panel and an 8-inch opening reference.
That makes it a different choice from every motor-focused repair in this list. Your existing ceiling cutout, duct arrangement, and electrical connection need a separate fit check before this complete unit makes sense.
Where It Excels
- The light-free design keeps the installation focused on ventilation.
- A compact 10-inch panel suits an 8-inch ceiling opening reference.
- A complete fan avoids sourcing a separate housing and grille.
Less Ideal Details
- The 8-inch opening reference may not match a housing designed around the Fitop dimensions.
- This option does not preserve an existing compatible fan housing.
Core Details
The Right Fit
You benefit most with an eight-inch ceiling opening and a preference for a complete, light-free ventilation panel.
Consider Something Else When
The Fitop 80 CFM 1.0 Sone Vent Fan better serves a new installation with a defined 4-inch duct and a 7.3-by-7.6-inch opening.
How To Match A Bathroom Exhaust Fan Repair To Your Housing
Start With The Housing Label
Read the model and part numbers from the housing before considering a replacement motor. Those labels tell you which electrical, mechanical, and airflow specifications matter, while the motor bay may reveal the shaft, rotation, and blower size.
Photograph the wiring and mounting area before disassembly. A clear record helps you restore the connections and makes an unmatched replacement easier to identify.
Match The Motor And Blower
CFM means cubic feet per minute, the rated volume of air moved by the fan. A motor with the right wattage or amperage can still be unsuitable when its blower or shaft does not match the housing.
Rotation also matters. Clockwise and counterclockwise motors occupy similar-looking spaces, but their shafts are arranged differently to pull air in the intended direction.
Decide Between Repair And Replacement
A motor repair makes sense when the housing, grille, ductwork, and wiring remain serviceable. A complete fan becomes more practical when the housing is damaged, the opening is wrong, or you want a different airflow and sound configuration.
Disconnect the electrical supply before handling either type. For complete ceiling units, verify the opening and duct size before removing the old fixture.
Common Mistakes Worth Avoiding
Wrong Turns To Avoid
A matching brand name is not a complete fit check. Compare the exact housing model, motor part number, shaft dimensions, rotation, blower diameter, and electrical rating before ordering.
Replacing only the motor while retaining a damaged or mismatched blower can also complicate the repair. Check the housing and blower together instead of treating each component independently.
The Upgrade Payoff
A higher-cost complete fan can justify the added expense when it provides the airflow, sound level, damper, or housing fit your current setup lacks. A premium-cost motor option is harder to justify when your existing housing already matches a straightforward component replacement.
Frequently Asked Questions For Bathroom Exhaust Fan Replacement Kit
How Do I Know Which Bathroom Exhaust Fan Motor Fits?
Compare the replacement part number and model list with the label inside your housing. Shaft size, shaft length, rotation, blower dimensions, mounting studs, and electrical ratings provide a second layer of confirmation.
Can I Replace Just The Motor Instead Of The Whole Fan?
You can replace just the motor when the housing, grille, wiring, blower, and mounting system remain intact and match the new assembly. Replace the complete unit when the housing or duct arrangement needs a different configuration.
What Does CFM Mean For A Bathroom Exhaust Fan?
CFM measures the fan’s rated airflow in cubic feet per minute. Higher ratings support stronger ventilation, but the motor and blower still need to match the housing mechanically.
Is A Reversible Motor Easier To Install?
Reversible rotation gives you more options for orientation, although the shaft and mounting dimensions must still align. A fixed-direction motor can fit correctly when the original housing specifies that direction.
Should I Replace The Motor And Blower Wheel Together?
Replacing both can help avoid combining a new motor with an aged blower. This option makes the most sense when the listed replacement parts are supplied as one assembly and the housing supports that exact combination.
Final Verdict
Start with a motor repair when your housing and listed dimensions line up, then choose between the 50 CFM and 70 CFM assemblies based on the original equipment. For a new installation, the Fitop offers a complete low-noise configuration, while the Orsong panel fits a different ceiling-opening profile. The correct part is the one that agrees with your housing in every measurable detail.