Insurance companies and state fire marshals require you to have smoke detectors in your house, and when one does its job and alerts you to a fire, you’ll be glad you have them. Until that happens, the best smoke detector is a quiet one. But, unfortunately, false alarms do occur. One cause is high humidity. To understand why this happens and how to prevent it, it helps to understand how your smoke detectors work. The short explanation is that some smoke detectors have a hard time distinguishing moisture particles in the air from smoke.
Smoke and Water
A fine mist of atomized water particles floats around in humid air, and while the average person can’t detect it, a smoke detector can. The mist can disrupt an ionization or photoelectric beam in much the same way that smoke does, with ear-splitting results. The humidity may be hanging around in a poorly vented hallway or it may be coming from the laundry room. Dryers are notorious for spewing damp air.
Steam from the shower is actually visible to the eye, which makes it even more likely to trip a smoke alarm. Ionization detectors are more likely to mistake humidity for smoke than photoelectric ones. That’s because the water particles attach to the ionized air particles and disrupt the electric flow to the sensor plate in much the same way that smoke does.
The hush button is your friend when a false alarm occurs. Some states, including California, require manufacturers to provide this feature. It’s usually located directly on the front of the cover, and pressing it stops the horn from sounding.