Dear Mr. Electrician: What is needed for a bathroom fan motor replacement? The exhaust fan in my bathroom stopped working after making noise for several weeks. Does the entire bathroom fan housing need to be replaced?
Answer: A successful bathroom fan motor replacement begins with having the correct replacement parts. In many cases a residential bathroom fan motor can be easily replaced.
Quite a few bathroom fans were manufactured for a simple and fast installation by the original installer. Consequently the parts replacement can be almost as simple. NOTE: Some text links below go to applicable products on Ebay, Amazon, or to my book.
The fan motor above is held in place with two screws supporting the bracket (Note the pear shaped slots). The electricity is connected with a plug. The housing is already grounded from the power supply, so when the motor gets mounted securely, ground continuity is maintained.
BATHROOM FAN MOTOR REPLACEMENT
The key to a successful bathroom fan motor replacement is getting the correct replacement parts. Many bath fan replacement parts are available, but identifying the correct parts can be a chore.
When your bathroom fan was manufactured, a model number was labeled inside of the housing or on the fan motor support bracket. Not the number on the motor itself, though that number is sometimes helpful and worth writing down. The fan model number may be stamped into the metal or there may be a label glued inside somewhere.
Before working on the fan, put a drop cloth down and wear a face mask and eye protection. Old bathroom fans sometimes have an abundance of dust and dander inside. Use a ladder when reaching up for the fan. Read my post about safety precautions.
When replacing the motor, always replace the fan blade. Don’t try to use the old fan blade with a new motor. It is difficult to remove the old fan blades and they can get damaged. Sometimes the bath fan motor replacement is sold as a kit with bracket, motor, and fan blade.
For those of you with a Nutone 696N B Unit bathroom exhaust fan, the factory has a replacement kit available. The Nutone C350BN is a motor, fan blade, and bracket all ready to be snapped into place.
Some Nutone and Broan model bathroom fans that were originally installed by the builder of your home have a retrofit bath fan upgrade kit available to change out the motor, fan blade, and grill while the existing fan housing remains in place. This is the easiest thing to do, and the manufacturer claims an improvement in noise and air movement. The kit is sometimes cheaper than buying the replacement parts.
The bath fan upgrade kit is a Nutone 690NT and can be used to replace motors and upgrade several models of Broan and Nutone fans, but not all. Note that Broan has an identical upgrade kit with the part number 690 and a different color box. Nutone and Broan are the same company. They merged together many years ago.
UPDATE: I have read recently that the 690NT has been discontinued. The replacement for the 690NT is a Nutone Quickkit #QKN60 for 7.5″ x 7.25″ housings. I have not used this model, but below are photos and description of a Nutone 690NT bath fan upgrade kit installation.
I am guessing that the QKN60 will be a little bit easier to install as it appears that no assembly is required. Unlike the 690NT, the Nutone QKN60 has the motor already attached to the bracket.
It will probably take longer to get out the ladder and clean the existing fan housing than it will to actually install the new fan motor.
The Nutone QKN60 will only fit on the following model fan housings: Nutone 695 and 696N, Nautilus N671 and N688, and Broan 670, 671, 688, 689.
Sometimes I found that my most difficult challenge with a bathroom fan motor replacement was getting the grill back on. It is usually because the bathroom fan housing was originally mounted too high above the finished ceiling instead of being flush as required.
I surmised that the original bath fan installer did not know that double drywall or resilient channel was going to be installed. More about this in my book.
The two mounting brackets and wrench that come inside of each Nutone 690NT Bath Fan Upgrade Kit. I list all of the model fans that can repaired or updated using the Nutone 690NT kit in my book “Almost Everything You Need To Know To Repair A Bathroom Exhaust Fan In Your Home”.
The kit will have instructions and a small wrench in addition to a new motor, fan blade, grill, and two mounting brackets. Basically you will be attaching the new motor onto the new proper size bracket and putting it into the existing fan housing that is already in the ceiling. The motor is held in place on the bracket with two nuts that are furnished with the wrench.
There is also a flexible plastic strip that gets inserted into the housing to direct the airflow.
In brief, you remove the existing motor and the attached fan blade, which is mounted on a metal plate that is held in place with a screw(s), nut(s), or sometimes just snapped in. The motor unplugs from a small electrical receptacle inside of the housing. When using the upgrade kit there is no reason to do anything with the wiring. The new motor will just plug into the existing electrical receptacle (Assuming that there is nothing wrong with the receptacle).
Before installing the new motor, clean the inside of the fan housing and check the backdraft damper to confirm that it moves freely. More information about this simple retrofit is in my repair book.
A visitor to MrElectrician.TV wrote to me and told about needing a replacement backdraft damper because one of the tabs had broken off. Unable to find a new one, he got the old one working with a piece of coat hanger wire. No further details.
I usually write the model number of the existing fan housing somewhere in the back.
In the above photo the 690NT motor and fan impeller is fully assembled on the counter top before being inserted into the fan housing on the ceiling.
The new mounting bracket has two tabs one one end that slip into the slots in the fan housing. The other side is held in place with one screw next to the electrical receptacle.
With the new motor and grill installed, the old bath fan looks like a new model and sounds a little better too.
See the Nutone 690NT replacement video below
I remember one time having to repair a customer’s fan that did not have a model number anywhere. I recognized the brand and called the customer service telephone line. I described the fan and the person at the factory was able to give me the correct model number and also sold me the correct parts. After I installed the new parts I made a point of writing the model number inside of the housing with a paint pen.
My free repair book provides contact information for most bathroom fan manufacturers.
MY FREE BATHROOM FAN REPAIR BOOK
I wrote a short book about repairing bathroom fans. “Almost Everything You Need to Know to Repair a Bathroom Exhaust Fan in Your Home” is available as a free download by clicking here.
Replacing the bathroom fan motor can be just a few simple steps that a novice can complete. You need to find the correct replacement parts. My repair guide can help with that.
I also suggest tools that may be needed, in addition to safety information. In my guide I list the contact information for most of the bathroom exhaust fan manufacturers and other suppliers of bath fan replacement parts.
As an electrician I have installed, replaced, and repaired many models of bathroom fans. There are certain factors that contribute to the optimum performance of a bathroom exhaust fan. There are also a few things that a homeowner can do to maintain a bathroom fan and keep it running for as long as possible. One important tip is to be sure to obtain the correct replacement parts when attempting a repair.
Many bathroom exhaust fans can be serviced by a novice with a few simple steps.
With all of the bathroom fans that I have repaired, one common problem was prevalent in all of them. Read what it is in my book.
A Total of 19 Free Easy-to-Read Pages divided below:
Safety – When you work around your home, you take some of the same risks as a professional. You need to protect yourself.
Diagnose – Things to check for optimum bath fan performance.
Identify – The correct model number and specifications for your fan.
Repair – How to replace the parts on your bath fan.
Prevention – Get the longest life from your bathroom fan.
Tools – Tools and materials that may be needed.
Parts – Where to obtain the correct replacement parts.
Glossary – Terms related to bath fan installations.
If you want a better quality bathroom exhaust fan that is much quieter, I suggest a full replacement with a Panasonic Bathroom Fan. I like the WhisperFit series because they are compact and come with a 3″ to 4″ duct adapter as the fan is rated for both 3″ and 4″ air ducts.
The Panasonic bathroom fans are made for retrofit as well as new construction. I have done several retrofits with the Panasonic fans and they all turned out well. However this is not a job for a novice. Some skill and a variety of tools are needed to successfully replace a bathroom fan.
If you have access to the fan from above the ceiling such as inside of the attic or a crawl space, then the replacement job can be a little easier, if you don’t mind working in an attic or confined space.
You will need tools for cutting the drywall, tools for working with metal duct, tools for working with wiring, and some supplies such as metal foil duct tape, and flexible air duct. A good sturdy ladder to work off of is very important for your safety. Goggles and a headlight are very useful. When climbing in the attic it is good to have work gloves, knee pads, and a dust mask.
Unfortunately there is no set method for a full bath fan replacement. There are too many variables. Some existing bath fans are more difficult to remove than others. Sometimes the air ducts are crazy. I found one where there were water pipes in the ceiling crossing over the fan. In another I found the exhaust air duct from one bathroom was connected to the exhaust air duct in another bathroom.
You should determine ahead of time what size duct is connected to the existing fan. The best way is to remove the existing fan as I have seen 4″ duct connected to a 3″ duct opening on the old fan and 3″ duct connected to a fan with a 4″ duct opening.
When I do a bath fan replacement for a client I bring along duct supplies for 3″ and 4″ exhaust air duct. It’s easier than having to run out and buy needed supplies in the middle of a replacement job.
Remove the electrical wiring carefully. Do not cut the wires. They are all that you have to work with. You may be able to get some slack out of the wiring by removing a staple or two after the fan is out and you have a hole in the ceiling to work within.
In a good scenario I can replace a bath fan in about two hours. In a bad scenario it took me over four hours. The good news is that in almost all replacements, I did not need to repair or paint the ceiling. The ones that did need ceiling repair were instances where the homeowner wanted the fan relocated.
Nutone also has their own line of retrofit fans in their Ultra Pro Series.
Read my post on safety before repairing your bathroom fan.