All units have fans installed in their bathroom ceilings. The fans vent air to the outdoor balcony. A properly working exhaust fan supports heat savings in winter as windows can remain closed. Such a fan also supports a reduction of in-unit relative humidity and condensation on windows. You should run your fan each time you have a shower.
As they age, many of these fans become quite loud as they wear and some eventually stop working altogether. Typically the electric motor wears out and fails so replacements are required.
Most stores sell only complete bathroom fans, i.e. the covering grille, the internals and the external housing.
While it is possible to replace the complete outer housing, all internals and the cover grill, this is a complex job. The original bathroom fans in our building were installed such that their metal outer housing is literally cast in concrete. Removal is quite difficult and often requires subsequent repairs to the surrounding ceiling.
Most economical and simple is to limit replacement to the fan motor and the fan blade. All other parts are cleaned and stay in place.
While many suppliers cannot find a suitable cross-reference to modern fans, our Superintendents have sourced a complete off-the-shelf fan assembly that can be purchased in many stores. The motor and fan blade of this assembly can quite easily be installed mechanically in the original fan box in the ceiling. The electrical connection is by means of a plug within the fan box. No electrician is required.
The NuTone basic fan, model 696NC, is currently available and has the fitting internals. It is fairly straightforward to remove the motor and fan blade from the new 696NC unit and install them in the existing, original bathroom fan housing as replacements. The rest of the 696NC unit would be scrap. The complete material cost is about $27.00 + tax.
Bathroom fan maintenance or replacement are the responsibility of the unit owner. The Superintendents can be contacted to assess if the 696NC motor and fan blade will fit the fan installed in your unit.
If you need a contractor to help you please contact me.