I live in a four year old townhouse that has them in it. Almost anything makes them go off. They drive me (and the other residents of the complex who have them too) crazy. Paul, give us an update in a few days on what you think of them.

Great. Yet another thing I'm going to want to hit with a hammer, as if my smoke detector isn't bad enough.

My CO detector plugs into an outlet and had battery back-up so I don't have to change then very often. NOTE! carbon monoxide is heavier than air so CO detectors should be located close to the floor. A CO detector on the ceiling or high on a wall is next to useless.

Can you test to see if it works? Thought about getting one, but how do you know it isn't just a flashing light? Sometimes our cooking tests our fire alarms.

Yeah, just one more thing to make noise. This is an awfully roundabout way to keep people from burning charcoal indoors, and no, those people aren't going to replace the batteries. If they were hardwired, and they worked properly and could be silenced, I still think it'd be BS, but it wouldn't bother me as much. As it is it's totally useless.

@#3 - that is good to know. We have one, but I haven't thought to check it lately, so it has probably expired. I heard they are only good for like five years.

Damn, Paul. I hope you aren't sick with the cold I had before Thanksgiving, which I am only now finishing. I doubt it, because I am across the country from you, but this one is nasty. My boss brought it back with him from Europe. This virus did not follow usual colds (which I haven't had in a while). I am glad you are home because when you are sick you aren't going to get better in the "The Stranger" office!

@3: "carbon monoxide is heavier than air ... A CO detector on the ceiling or high on a wall is next to useless."

What's your source for this?

@7 a degree in chemistry and the instructions that came with my CO detector.

Gotta love those nanny-state commenters. As if every last one of them isn't alive today because some nanny-state bureaucrat set up some kind of law or regulation decades ago to ensure they could go from blood-covered squealing brat in the delivery room to cheese-dust covered squealing brats behind their keyboards.

@8: So when the epa and other places say things like "Carbon Monoxide is lighter than air, so detectors should be placed closer to the ceiling" they're completely wrong?

http://www.epa.gov/aging/resources/after…

Oh, for the love of god. You can't fix stupid. A little box on the wall won't keep indoor charcoal burners from earning their Darwin awards.

@3, 7 and 8 that was yummy. My building is putting them in tomorrow. I hope mine doesn't go off when I sear. I am very big on searing. (Source: high school dropout, college dropout.)

Yeah, all the sources I'm finding say "CO is lighter than air".

http://chemistry.about.com/od/howthingsw…

http://www.firstalert.com/faqs/co-alarm/…

Science also says density doesn't much matter, especially since the densities are so similar. Convection currents and particularly temperature matter much more. Note that any CO in your home is probably a product of very recent combustion (i.e., charcoal grill) it's probably warm, and it's heading upward.

http://www.newton.dep.anl.gov/askasci/ch…

Hearing about Vitas Gerulaitis scared the crap out of me. It's been open windows and/or CO detectors ever since.

@12, I'm big on searing, too. In fact, I'm rather famous for searing things that no one else has ever thought to, like rice, beans, tortillas, soup, steaming vegetables, plain water, empty pans.... My technique is to put the burner on high and then walk away and get absorbed in a book or web page until I smell smoke from the other room.

Just to add some actual numbers to the density discussion... CO is ever so slightly denser.

CO at sea level = 1.977 kg/m3
Air at sea level = 1.2 kg/m3

Source wikipedia

@16, Thank you. Facts continue to be stubborn things.

When I was quite young, a co-worker of Papa Vel-DuRay became gravely ill at Christmas, along with the rest of the family. They all thought it was the flu, but even the family dog was sick.

It turned out it was a defective gas furnace, and all of them - including the dog - died.

While furnaces have undoubtedly been improved since then, that was enough for me to always have a CO2 detector in any place that I lived that had any sort of natural gas service.

My bf and I thought this was already required by some law. In fact, I think it might have been the home inspector who told us that last year before we moved in to the new house. So we installed one in the stairwell outside of our bedroom, at the same height as a light switch. We've never heard a peep out of it, except for when we use the test button.

So can your landlord just waltz into your apartment unannounced to install this thing? Because mine did. Aren't they supposed to give you a notice before they enter your apartment? It creeped me out a bit, and now I wonder if he can just come in at any moment. Is this something I should bring up with my rental agency?

@15, nothing says "dinnertime" like leaping to find a broomhandle to poke at the tiny button on the ceiling-mounted smoke detector.

@20, you are owed notice except in case of emergency or while you are bathing.

Actually the density of CO is so close to that of N2 (the main component of air on earth) that its distribution in air is more or less uniform. Convection and other movements of air will keep things sufficiently stirred up that where you put the detector doesn't really matter.

Some have reasoned that it makes more sense to place the detector higher, because combustion products (including CO) tend to ride convection currents up when there is a fire. Of course, if this is the case, you have bigger problems than a level of CO than you need a detector to know about.

Similarly, if there is enough CO in a given space that you will actually detect more of it at ground level than you would a few feet higher, you also have a much more serious problem.

@16, that's not how sources work. Post a link. Here's wikipedia on the subject:

http://en.wikipedia.org/wiki/Carbon_mono…

Make a note of some particular facts: "Carbon monoxide has a molar mass of 28.0, which makes it slightly lighter than air, whose average molar mass is 28.8. According to the ideal gas law, CO is therefore less dense than air. "

The numbers given are 1.250 kg/m3 at 0 °C, 1 atm, 1.145 kg/m3 at 25 °C, 1 atm ("m3" is supposed to be m-superscript-3, but Slog doesn't do superscript). Air is around 1.225 kg/m3 at 15 °C, 1 atm. Thus, unless your house is kept at freezing temperature, CO is less dense.

I don't see your figures in the article for CO. I do, however, find your "CO at sea level = 1.977 kg/m3" figure in the article for CO2 (superscript 2). CO2 is not the same thing as CO. So, uh, you're using the wrong numbers for the wrong gas.

@17 take note.

@21, as if that tiny button ever does anything. I have to take the battery out.

When I was younger my father left a pot of rice on the stove and I had distracted him long enough that the rice burned. The whole house smelled of burnt rice for days and days.

Then there was the afternoon when I was making some crab cakes on the stove and the damn WWU Birnam Woods apartment alarm went off. I probably scared half a dozen fellow students.

Just finished checking the fire alarms and found two out of three working. The one from like the 1980's still works brilliantly. The one not working didn't detect any smoke. The test button works but it wouldn't alert me to smoke even though I put the thing right over the test candle I was using.

@24 damn you're right.

volunteer firefighter here - as annoying as they may be, i've seen them save lives. your furnace, fireplace, water heater, dryer, car, or some other form of incomplete combustion can kill you in your sleep. elderly man left his car running in his garage by accident; nearly killed himself and his neighbors - only reason he survived was because he was on oxygen. he was passed out but his CO detector going off was driving somebody else nuts so they called us. they're worth it.

@28, that makes sense and I can get behind a law to protect renters from accidents or leaky gas. If, though, as the post suggests, the law is meant to protect people who use charcoal and/or gasoline indoors, then it IS a "nanny state" instance. How many warning labels (with pictographs!) does it take to save someone from killing themselves and their families?

Ah, one of the good things about "all electric living"...

There is a product to test them fully - its safe and very easy to use. when you press the test button on a co alarm it tests the electronics and not the sensors ability to sense the co gas.

see the nfpa720 on testing co alarms and in the standard it says to test them on installation and every year with an external source of CO Gas.

take a look at www.detectagas.com

CO Alarms do save lives - but only if they are able to sense CO Gas. There is a good product out there to test CO Alarms. When you press the test button it tests the electronics only and not the sensors ability to sense CO Gas. you could be pressing your test button and the alarm will flash and sound but it may not be able to sense CO for some reason.

see the NFPA720 - which states that you should test with an external source of CO Gas on installation and once a year afterward.

see www.detectagas.com

Typical CO Alarms that you can purchase at the store are built to meet UL 2034 standards. That means that the alarm will begin to sound when CO levels reach 65-75 ppm for at least 60 minutes or 145-155 ppm for at least 10 minutes or 390-410 ppm for at least 4 minutes. They also have a built-in "False alarm" delay feature that keeps the alarm for sounding at levels of 27-33 ppm for 30 days or 65-75 ppm for 60 minutes.

This standard is "alarming" in and of itself.

OSHA says workers shouldn't be exposed to more than 50 ppm in an 8 hour day. NIOSH establish a standard of 35 ppm in 8 hours and ACGIH set their threshold to 25 ppm. A UL 2034 alarm wouldn't even issue an alert at these levels.

There are low-level CO monitors out there, but you can't get them at the store. Do a Google search for "NSI 3000" and you can learn more about this style of low-level protection.

If your alarm is over 5 or 6 years old, it probably needs to replaced. The detection technology used in these devices has a shelf life of about 7 years max. They are too important to risk the consequences!

You can also learn more at http://www.stopcarbonmonoxide.com/