USI Plug In CO & Natural Gas Alarm

Has anyone tried this.

There was talk last time that wall plugs are too low–gas rises and by the time it gets low enough for the wall plugs–you’re already smothered in your sleep.

This is a good deal. I almost jumped on it, as my last CO detector has sniffed its last breath. However, I’m a stickler for needing a digital display on these things.

Yes, this will warn you to get out of the house when the level of CO reaches a dangerous level. I want to know about it before then though…if the display is ever reading anything other than 000, then I want to start investigating what the problem could be before it becomes a real issue.

Incidentally, these things start a countdown-to-death timer the very first time you power them up. Five years later (seven on some models), it will stop working and tell you it needs to be replaced. This is a safety feature…it’s a good thing. However, don’t ever buy one of these used (or “open box”), even if the seller says it was only plugged in “once, just to test it.” That means the clock has been counting down ever since.

My current and somewhat old CO detector is on the 2nd floor and plugged in to a wall outlet.

Actually, in the end it doesn’t really matter where the alarm is. Check out thisrather informative site if you don’t believe me.

In the end, nothing really matters.

EDIT: That is an informative site. :slight_smile:

Will put this in my 9 yo’s room after beanie weenie night

This is a common misconception. CO is very slightly lighter than air, so one would expect it to rise. However, it’s so close to the same molecular weight that it gets evenly distributed by air currents…it essentially becomes part of the air. You can mount a CO detector high or low, and it will still sense the CO just as well.

To explain this in a bit more detail: CO is lighter than the oxygen we breathe (O2), but weighs the same as the Nitrogen that makes up the rest of air (N2). N2 is 78% of what we call air, with O2 being the other 21%. In air, the N2 doesn’t rise to the ceiling while the O2 falls to the floor, despite the difference in atomic weight…if it did, we’d suffocate when we stood up. Same thing applies here, the CO is the same weight as N2, so it gets evenly distributed in the room.

Gas alarm. Why would I buy an alarm that is going to go off every 5 seconds in my room?

Much has been made of the fact that CO and Natural Gas (methane) is lighter than air, thus rises to the ceiling. The problem is that most household outlets are placed low, so this detector would be installed too low to be effective. In fact, it would normally be lower than a sleeping human’s nose, rendering it dangerously useless.

I just got mine from the last Woot. The manual is one of the best written that I’ve ever read. BUT … it’s very disappointing that this issue of height is not even mentioned. So should we buy this?

I think yes because there is an easy fix. Simply take any old two prong electric cord, or buy a cheap extension cord. Then cut it, exposing the two bare wires that go to the prongs. Now insert the bare wires into the HOLES of the prongs of the detector’s plug. Since the device is polarized, it doesn’t matter which wire goes into which prong. YOu can now either solder the wires to the plug, or merely twist the on securely. Then take a pair of pliers, preferable vise pliers, and bend the prongs open until they are flushed against the back of the detector (bend the left prong left, and the right prong right). Make sure the wires don’t come loose and you don’t break the plug. Make sure the two wires don’t touch each other in any way, including single loose strands. Then put lots of insulating tape all over the wires and plug.

Voila, now you have a detector with a cord that can be placed HIGH flushed against the wall. I prefer to use Velcro tape for mounting.

Exactly, the sensors start deteriorating once exposed to air. That’s why the detectors comes vacuum sealed.

Eat less chili, dude!

I think you’re more likely to mess something up or injure yourself when, in the end, it doesn’t matter where the alarm is placed. PLEEEASSEEEE go through the site I previously posted because all of this re-wiring is absolutely unnecessary.


This is very informative - thank you!

If you only have one, it should be on the same floor as possible CO sources…furnace, stove, fireplace, etc. However, you really should have at least one on every floor. If the one in your living room goes off because of the fireplace, will it wake you up upstairs in the bedrooms?

The best route to go in my opinion is to get the detectors that link together into a network. First Alert calls them ONELINK, and I’m sure their competitors all have something similar. The idea is that if one detector triggers, they all sound the alarm. They make a ONELINK combination smoke/CO alarm that you can get at Amazon for around $50 last I checked. It’s not cheap, but it’s two detectors in one and it is a life-saving device.

Found it:

Thanks for the info but it’s dangerously misleading and incomplete, especially in this context. Here’s why: Many CO detectors are built into a smoke detector. And in this case, it’s built alongside a Natural Gas (methane) detector. Both smoke and methane are indeed lighter than air and rises to the ceiling. Smoke rises because it is heated and natural gas rises because methane is molecularly lighter. That’s why all smoke detectors tell you to mount them high, preferably the ceiling.

Please also consider that most household sources of CO are heated. Warm gases rise. In other words, the heated CO rises before blending in with the normal air. So if seconds matter, it might help to mount a CO detector high.

By using that site to justify plugging this low ignores the fact that this is also a Natural Gas detector. In fact, it’s the reason I bought this. I live in a NYC apartment and have no real need for CO detectors. But several times, the flame on my gas stove was extinguished by a fan (and once extinguished by an overflow of liquid) leading to flammable natural gas throughout my kitchen. Having allergies, I was not able to smell the gas. Nor would I smell it if I dozed off. So mounting this up high, or at least nose level when I sleep, is indeed important.

Another thing to consider is that a lot more dust is at floor level. That makes clogging the sensors more easily. And I believe air flow is worse at floor level, especially when there is no movement in room, i.e. when I’m sleeping. My guess is that a high detector would react quicker.

You’re ignoring the fact that the CO often comes from a heated source. That, in itself, makes it more likely to rise – before settling and blending with the air. N2 isn’t warmer than air in any normal home. So if quick detection is your goal, mounting high is better.

I also mentioned in another post that many CO detectors are built into smoke detectors. There is no debate that smoke rises (once again, because of heat) which is why every manufacturer recommends mounting high on the ceiling. As such, it’s dangerous for people to assume that since the smoke detector also monitors CO, placement wouldn’t matter. I believe natural gas also rises, so this particular combo detector should indeed be mounted high.

In other words, placing it high has no downsides (besides aesthetics), and may even result in quicker detection of heated CO.