Electrical – Bathroom in-wall exhaust fan with dimmer


In searching this SE, I see many questions discussing traditional ceiling fans and dimmer switches.

This question revolves around bathroom in-wall exhaust fans and dimmer switches. Is it safe to replace a standard on/off switch with a dimmer switch for an in-wall bathroom exhaust fan? Will doing so quickly destroy the fan?

The fan is a standard construction-grade inexpensive in-wall exhaust fan.

The idea is to conserve energy and reduce fan noise.

After my mother-in-law cooks a meal, it can be turned up to full power in order to handle the increased noxious vapors in the bathroom due to all the urgent visits. Otherwise, it can be used at lower levels.

Best Answer

This kind of fans usually use a shaded-pole motor. From wikipedia:

they are compatible with TRIAC-based variable-speed controls, which often are used with fans

So it appears the fan should be fine.

But there is some risk to the dimmer due to voltage spikes generated by the inductive load. You could try to find a dimmer switch that is rated to control inductive loads, or you could just try it out. A typical fan is pretty low powered device and a typical dimmer might be able to handle the small inductive spikes it will produce.