Tuesday, May 22, 2012

Let's Talk About Smoke Detectors a Bit

I've been having a continuing problem with smoke detectors.  My house is wired for them and each one will connect to the others such that an event in one room will set off the entire house.  That's nice as a protection feature, but not when they false.  The experts call this a 'nuisance alarm'.  Nuisance is right; at 2:00 AM when you get a fire alarm, the dogs shoot outside and hide and I have to wander the house trying to figure out which one is messing up.  Then after ripping the offending device out of the ceiling and dropping it on something horizontal nearby, I have to go round up the dogs and convince them to come back inside.

Sure, I've heard all the arguments about safety.  How a fire that starts in one room can trap you in the house and the earlier it's detected, the safer one is.  Fine, but don't tell me that at 2:00 AM while I'm wandering around the house trying to see that little red light on the smoke detector.  It's easy to check for a fire, just sniff or check out the room in the dark.  Never had a fire, but have had a few hundred false alarms.  Clearly, I'm not understanding something here.

In order to pass the final inspection the contractor put in ionization smoke alarms with battery backup.  All the alarms have power provided, and have a separate wire running such that they can communicate with each other.  Nice setup if the devices actually worked as advertised.  Within the first week, I disconnected the one in the kitchen.  Seems every time I cooked, it went off.  About a month later, I disconnected the one in my den.  Seems it went off every time I turned on the ceiling fan.  After a year, I disconnected the one in the master bedroom.  It went off with the ceiling fan also.  Eventually, I only had one hooked up; it was in an unused bedroom.  Over time I would reconsider and hook them back up (new batteries of course) and start the entire process of getting disgusted with them and disconnecting each one in turn.

There was a turning point last year when I decided to use the evaporative cooler in my garage to cool the house during part of the year.  I turn on the cooler and open the door from the house to the garage and allow the air to flow through the house.  I can control which rooms are cooled by opening or closing doors such that the space humans are in is comfortable.  This makes it nice since I can have open doors and enjoy the outdoors without getting too hot.  However, the freaking smoke alarms reacted to the increased humidity and sounded off.  In disgust, I replaced every one of them with a newer model that didn't have a battery.  Those batteries never last as long as they say and chasing down a battery failure in the middle of the night is as big a pain as a nuisance alarm.

This lasted about a week and I had to disconnect the one in the kitchen again; then the den, then the master bedroom.  Over time, I had to disconnect a number of them to get a night's sleep.  Clearly, I wasn't doing something right so I talked to my neighbors.  Without exception, they had disconnected most of their house's smoke detectors.  One guy actually modified his to have the little light on, but broke the sounder.  Seems his wife wanted the protection of the detector, but complained about it sounding off in the middle of the night.  He saw the modification as his best solution to his particular problem (as in wife).

OK, so did some research on the detectors themselves.  There are two extremely common forms of detectors, ionization and optical.  The ionization ones react quickly to smoke while the optical ones take a bit longer.  The ionization ones, being more sensitive, tend to nuisance alarm a little more often.  Fine, I'll try a couple of the optical.  After installing them and having success, I relaxed.  Then came evaporative cooler time; nuisance alarms started all over again.  Back to the drawing board, I tried various experiments on both kinds and just couldn't figure out why they were firing off in the middle of the night and being nice during the day.  Never did.  However when I read many, many complaints similar to mine, I decided that, not only was I not the only person in the world to hate these things, I was only one of a silent majority.  We're silent because there just isn't a good solution out there.

See, these devices are subject to a ton of possibilities.  Increased humidity such as evaporative cooling or a bathroom shower will cause both the optical and ionization devices to fire.  A random spider will set off an optical device.  Dust will cause both kinds to go off.  The list just goes on and on.  People on forums and in reviews love to say, vacuum it out every three month to be sure they stay clean.  Ever tried to drag a Dyson up a 10 foot ladder to vacuum out a smoke detector?  I used to go up and take the thing down, carry it out to the garage where the compressor is and blow the darn thing out every three months.  Didn't do a bit of good.  Of you folks that have smoke detectors in or near the kitchen, how many of them are still connected?  There's a bunch of folk out there that have given up on the ones near the kitchen since they seem to fire every time there is company over.  Cooking and smoke detectors don't mix.

But, there is hope.  There is a device out there that may help my particular problem, a heat detector.  These things don't detect smoke, they detect changes in temperature.  Since heat rises, they will fire when the temperature hits 135F or rises 10 degress in a short period.  Sure, proper ventilation will keep the temperature constant in a room and delay these things going off, but I will get to sleep and have a lot more protection than the device setting on a bedside table because it sounded off for no reason two nights in a row.

I'm not going to bore you with the technical details of how the various kinds of devices work and the options available, google is your friend if you want more information on them.  But, here's my plan.  I'm going to replace the kitchen, den, and master bedroom devices with temperature detectors.  Then let them run a while.  I'll leave either optical or ionization devices in the other areas until they give me problems and decide what to do based on the results.  While I'm at it, I'll alarm the garage with a temperature detector as well since it doesn't have anything at all (local code didn't require it).

Note that since my house is mostly electric, I don't have any concerns about carbon monoxide.  Additionally, since I leave the doors open and fans running most of the year, radon doesn't worry me either.  See, there are advantages to living in the sticks in the desert.

Edit July 8,2012: Well I've had a heat detector in place where I was getting the most false alarms for a couple of months now.  No problems at all.  I put it in the kitchen and now I can burn dinner without having to mess with a false alarm.  So, anyone stumbling across this post, here's a solution that can maintain a modicum of safety without dragging you out of bed at 2 AM.


  1. Test comment .... Ah now Mr Google happy ... Here in Australia's I'm having first ever problem with evaporative cooler + ionisation smoke detectors... TURN Evap cooler off & alarms stop ... never had this problem in past ... Will have to clean Evap cooler ... Yes Dave I've read all of your post ... Maybe dust in the Evap cooler ducting ... Shall check weather reports for humidity levels ... G

  2. Dave ... We're experiencing unusual high humidity levels ... trickle down from cyclones over NW Australia ... I've been running Evap cooler overnight and charts have recorded humidity of 85% + ... May be final humidity levels across sensors far too high ... G

  3. How do I add an image .. screenshot of weather map?

  4. I don't think images can be included in the comments. I've never tried. Image tags can be inserted though, here's the URL to the instructions:


    One thing I found helps the silly smoke detectors; blow them out with some of that canned air they use for cleaning keyboards. That worked reasonably well on a couple of them. Don't use a compressor, way too much air pressure and it may blow some of the guts out the other side.

    It seems that dust builds up inside the detector and then the additional humidity sets the darn things off. Really, really annoying.