Why does using the blow dryer set off the fire alarm?

January 6, 2010 10:16 AM

Whenever my mom tries to blow-dry her hair, the house's fire alarm goes off. What could possibly be causing this?
posted by BuddhaInABucket to Home & Garden (7 answers total)

Is the fire alarm the kind that's wired directly into the house current? When I use my blow dryer, the lights dim noticeably. Maybe the drop in current is setting it off?
posted by JoanArkham at 10:19 AM on January 6, 2010

Best answer: I had this happen once. It was caused by bits of dust stuck inside the hair dryer. When the dryer turns on, the dust burns just enough to set off the fire alarm. Try cleaning out the dryer with a can of compressed air.
posted by amyms at 10:29 AM on January 6, 2010

Dust is causing this.

Get a new hair dryer. Ensure your fire alarm is relatively new, has a fresh battery and is kept clean (use some canned air to blow off dust).
posted by Cool Papa Bell at 11:08 AM on January 6, 2010

A single hair dryer should not cause the house voltage to dip, this definitely sounds like a wiring issue in the house. It's definitely worth seeing if this occurs in other places in the house (as Burhanistan suggests) but I would recommend having an electrician check things out in any case.
posted by tommasz at 11:11 AM on January 6, 2010

Is she using it close to a smoke detector? Where is she using the blow dryer? Most "smoke" alarms are actually just detecting heat; rather than smoke. The hot air from the blow dryer could set it off.
posted by spaltavian at 11:40 AM on January 6, 2010

tommasz: "A single hair dryer should not cause the house voltage to dip."

Have you seen some of the hair dryers these days? I have one like this, and I have to be super-careful about using it, because it can cause a fuse to blow.
posted by radioamy at 3:31 PM on January 6, 2010

I lived in a house once where the smoke detector was right outside the bathroom door, and when someone had taken an unusually long, hot shower, the alarm would get tripped by the steam. Maybe the dryer is a red herring?
posted by crinklebat at 5:52 PM on January 6, 2010