Sears Blue Climate Crew

Bathroom Fans

Bathroom fans are required by most codes where a bathroom does not have an operable window. The fan should discharge directly to the building exterior. In many cases, the fan terminates inside the house or roof space. This can add considerable moisture to a house, leading to condensation and rot problems.

Although fans are not required in bathrooms with operable windows, they are desirable in these rooms. In the winter months, one is not likely to open a window to dissipate the steam generated by a shower. This heavy concentration of moisture, particularly in a bathroom where showers are used regularly, can lead to premature failure of interior finishes such as paint and wallpaper, and result in mildew and rot in concealed areas.

Bathroom fans are notoriously noisy. This is particularly true of lower quality fans. The fan may be operated by a separate switch, or by the room light switch. Some fan switches are on timers, and others are on rheostats (so the speed can be varied). Neither of these is considered particularly important.

Many bathroom fans are inoperative, because the motor or fan mechanism has failed. Often, the fan has simply been disconnected by a homeowner, irritated by the noise.

The exhaust fan should provide at least twelve air changes per hour. For example, in a bathroom that is five feet by eight feet by eight feet high, the exhaust fan should have a capability of more than sixty-four cfm (cubic feet per minute).

Where the exhaust fan ductwork passes through unheated spaces such as attics, it should be insulated to prevent condensation. Exhaust fans should never discharge into chimneys.