According to different sources, the amazon reviewer is on crack and also the review is unhelpful.
Buy these, they are fine and effective in your house
Is this UL Listed?
Good point! When my wife farts it doesn’t take very long before the whole room smells. If that reviewer were correct the smell would rise to the ceiling. Shoot I would buy a house with 10 ft ceilings
Figured I’d read the comments until I ran into the first fart joke,5th comment in,not surprised
Leave it to a bunch of wooters to freak out about plug and gas detector placement.
PLEASE DO NOT LISTEN TO THE AMAZON REVIEW!!!
The person that wrote that review did NOT even buy this product.
I know from experience that this product is ETL approve to UL standards. you can not get that rating unless you meet all requirements by UL. This thing is great. It does NOT have to be plugged in on your ceiling to work. Buy, plug it in, and have peace of mind that you now have a CO and natural gas alarm working in your home.
There fixed that for ya.
Oh wait, Neil deGrasse Tyson is telling me that the earth does in fact have a gravity field. Sorry, your statement, like Pluto, is no longer valid. Gasses of different densities will form a gradient in a gravity field. (That’s why we have atmospheric pressure) True that the gasses in question are similar in density and should then mix quite easily, but they will not be in equal parts.
Wait, hold on again, Daniel Bernoulli is tapping me on the shoulder and whispering that what with doors opening and closing, the possibility of ceiling fans and air conditioning, people walking around, your room is not a steady state. Maybe at night when human activity is at a low you can approach a near steady state, but it’s still not quite there. Your statement is invalid yet again, the gases are not spread in equal amounts.
Remember kids, the ideal gas law is called ideal because it only exists in ideal conditions which do not occur naturally. We cannot simply take the assumptions made for experimental reproduction (scientific method) and apply them to real time scenarios.
There’s nothing wrong with having one of these plugged in, not at ceiling level. You just don’t want them plugged in near appliances that may set them off during normal use, or near a garage door. Make sure you have them near (but not in) a bedroom. If you live in a two story home, an upstairs hallway outside bedrooms is a great spot.
What I can’t find, which is the important part, is the year of manufacture for these. They should be replaced according to manufacturers instructions, But, generally, go by manufacture date, not when you started to use it. Same goes for smoke alarms.
NFPA CO Safety: http://www.nfpa.org/assets/files//PDF/Public%20Education/COSafety.pdf
First off, CO is almost as heavy as air and propane is heavier, so it’s unlikely to be detected on the upper floor unless you have a heater in the room or attic. Methane, however, is much lighter than air.
About this particular deal, as all these devices have a fixed lifespan from the date of manufacture are these old stock?
I would also like to know this, it is very important.
First Alert CO600 Plug In Carbon Monoxide Alarm $20 amazon free shipping eligible.
Is the gas detection feature that useful? CO poisoning is very rare. I am not hearing about gas explosions much at all. Quite a few Co cases involve people sleeping near outdoor generators. There aren’t that many cases. If you are really worried I suggest a talking CO detector as the beep will be confused with your smoke detector.
The owners manual (link below) answers a couple of questons mentioned here:
- The clock starts at power up
B) This realy is for methane, not propane
iii) I have way to much time on my hands
http://smokealarms.com/app/img/MCND401%20&%20MCN400_Manual_English%2002-2012_0.pdf
Ok Mr Wizard- explain this- Why don’t we all die since CO2 is heavier than O2? Whether you are speaking of steady state equalibrium or the fact that things are not in steady state and you have activity in the room- either way I win. The steady-state scenario will follow near ideal gas laws and the gases will diffuse on their own. The human activity model will mix the gases even faster- because you are agitating the environment. Maybe you got your information from Mike Tyson instead of Neil deGrasse Tyson.
Carbon Monoxide mixes readily with air, and will be affected by any movement or drafts. The difference in the gravity of air and the gravity of CO is not significant enough to create a gradient in your home, even in a steady state environment (which practically never happens in a home, anyway).
CO monitors can be placed anywhere. High or low, it will be equally as effective.
Natural Gas is another matter altogether. It is much lighter than air and may gather near the ceiling in a still room. But mercaptan smells terrible. You’re likely to smell Natural Gas before it reaches the explosive limit.
If you’re only worried about gas leaks while you sleep, this may not be the best product for your needs (Look for combination smoke/gas alarms).
If you are worried about CO or Propane, this will do fine. I already have smoke alarms, and a few CO alarms plugged in around the house. I don’t have gas in my home, so that isn’t a concern for me.
If you’re like me, this might be worth a woot.
I’m looking forward to the next time WOOT offers a lamp for sale. The whole discussion group is sure to come to blows over Ohms Law. 
Me? I am waiting for WOOT to offer bottled Oxygen. I have some technical points to argue at the molecular gastronomy level.
Their clock starts at power up. But, it’s the manufacture date that’s important when it comes to replacing.
I’ve got outlets in the ceiling of the basement where my gas fired heater, water heater and dryer live. It’s easy enough to install one, if you don’t already have one.
Because the atmospheric concentration of CO2 is 0.0394% or 394 ppmv (parts per million by volume) You can see for yourself here: http://co2now.org/
CO2 is not lethal until is reaches approximately 5-7% or 50,000 - 70,000 ppmv depending on your personal physiology. If our planet had that level of CO2, life would not exist as we know it.
However it is useful to point out that just 1 ppmt (punch per Mike Tyson) causes loss of consciousness and, again depending on your physiology, could be lethal.
You keep using that word. I do not think it means what you think it means.
So I guess we are safe, unless we decide to sleep on the floor.