This question comes from Alice, who had a problem with her bathroom fan.

My bathroom fan sounds like a garbage disposal, can it be fixed and is it really urgent?
Sorry to say, but if the bathroom fan is growling at you, you probably need a new one. What you are hearing is most likely the motor that drives the fan that blows the moist air out of your bathroom or the bearings that make the fan spin smoothly. In either case, when parts of an electric motor age, they may lose lubrication or can be affected by moisture by way of a worn gasket or seal. When looking for a new fan, be sure it accommodates the proper air volume for the size of your bathroom. Ideally, your fan should be completely changing over the air in you bathroom 5 or six times an hour. To figure that out: Just do a quick measurement of your bathroom before you go to the hardware store.
  1. Multiply the width of your bathroom by the length and then multiply that number by the height of your ceiling—this is the “cubic feet” of your bathroom.
  2. Multiply this number by eight (this is then the number of times we are wanting the air to change)
  3. Divide that number by 60 (to determine the Cubic Feet per Minute)
With that target volume in hand, it is just a matter of how much quiet you want to pay for. The sound of fans are measured in Sones, so the fewer the Sones, the quieter the fan... and the bigger the price tag. Another feature I suggest looking at is a timer. Different fans may use different methods, but in general, it is best to leave a fan running after the shower or bath in order to completely exhaust all of the moist air from the room. Simply shutting off the fan when you leave the room traps hot, moist air, which could damage cabinets, woodwork or promote mold. As far as difficulty goes—If you’re comfortable installing a ceiling fan or light fixture, you can probably handle this project on your own. If not, let us know and we’ll point you in the right direction. Thanks, David