Will I suffocate?

April 26, 2007 9:55 PM

How dangerous is it to live in a small room with a gas-powered water heater? Will I die?

I am considering living in a small (6' x 10') room with a slanted roof (10 feet on one side sloping down to 7' on the other). There is a hot water heater on the tall side of the room; the standard type found in california: 5' tall, raised off the ground, gas powered, vented to the outside world (not a enclosed vent, but one which is open at the top of the water heater, then there's a pipe which leads to the outside world). I would be building a loft bed on the low side of the room, and would likely sleep with the doors and windows closed.

I read that building a bedroom with a water heater is not legal, and that living in a room with a water heater is "potentially lethal" due to oxygen consumption or improper venting or something.

So; should I do this? What's the likelihood of me dying? Can I mitigate the risk in some way? etc!!!

posted by beerbajay to home & garden (17 comments total)

Can you get a carbon monoxide detector? They cost less than $30.
posted by croutonsupafreak at 10:06 PM on April 26, 2007

I have a carbon monoxide detector in our basement, not 3 feet away from the big gas water heater, and it's never gone off.
We had a tenant (on the other side of the drywall, but still close) for 4 years, too.
I think it should be okay as long as it's well vented to the outside, although it's hard to tell without seeing the room.
But for sure get a CO detector.
posted by chococat at 10:10 PM on April 26, 2007

I'd call the company that provides the gas and ask. Some places, they'll come out and check it for you, if you're a tenant, without charge.
posted by cookie-k at 11:59 PM on April 26, 2007

You probably won't die. It is against code to have the water heater in your room. I have lived in lofts with the water heater and the furnace in one not so big room. I didn't die, but the gas company did come through once and turn off my gas because they said the set-up was unsafe. I reconnected it. I was young. Get a CO detector.
posted by lee at 12:18 AM on April 27, 2007

Some years ago, IIRC, Atlanta's WSB-TV news person Carol Sbarge discovered that her water heater's exhaust flue had developed small pinhole leaks, and that her kid's, husband's and her own months long history of headaches and chronic fatigue like symptoms were alleviated within days of having it repaired. The home was only checked because her doctor put 2 and 2 together, after repeated visits by all family members, and viruses were ruled out. She's since maintain a personal interest in CO poisoning stories, and has filed several stories for the station, and generally does a CO safety reminder for the station at the start of heating season.

Carbon monoxide detectors are designed to protect healthy adults from life-threatening levels of CO. If your room has constant low levels of CO below that elevated exposure threshold, and you spend many hours there, you can still develop significant CO hemoglobin binding, which will not kill you, but you can feel poorly for hours outside the area each day as your body slowly dumps the CO, and your CO₂ levels then return to normal as your blood chemistry renormalizes. Then, you go home to sleep, and your CO exposure begins again, and you wake up with dull headaches, and feel slow and stupid for hours again. And CO detectors may not warn in time in situations where CO levels elevate slowly over several hours, affecting victims mental acuity adversely before they can be warned. Finally, CO detectors themselves have working lives of about 2 years (because of their detectors) and generally need to be properly installed, checked monthly, and have fresh batteries, to be even as effective as they are intended to be. So, my message is that you shouldn't buy a $30 CO detector and forget your risks.

If you must live in such a situation, you can mitigate your risks in a couple of ways, perhaps. First, be sure the heater's exhaust vent is in good shape, and venting combustion products outside, without leakage. Second, since CO is slightly lighter than air, keep your bed low. Third, if you have a window, and can keep it cracked for fresh air while in the room, do so.
posted by paulsc at 3:16 AM on April 27, 2007

When my girlfriend and I moved into our place here in Philadelphia, a guy from Pennsylvania Gas Works (PGW) came out to turn on the gas. Part of the process was inspecting our gas-using appliances. Our water heater, also in our bedroom, was apparently very out of code (the PGW guy was appalled by it, actually), so he tagged it as a hazard and could not turn it on. He then went to check out the other apartments, which had similar units, and tagged them too. The water heater was an open combustion chamber unit, which was the major problem. Regardless, the landlord replaced all of them with electric units, and we got a carbon monoxide detector regardless (we still have other gas appliances, and they're so cheap, it's pretty stupid not to have one).

So maybe call the gas company and have them send out a service tech; (s)he'd be able to tell you if it's dangerous or not. It does sound to me that the sort of heater you describe would be dangerous, though.
posted by The Michael The at 5:24 AM on April 27, 2007

While the water heater is vented to remove products of combustion, you still must provide a way for fresh air to enter the room for the venting to work properly. Opening a window while you are in the room would be a very good idea, especially while the water heater is actually on.

The problem is not so much a lack of oxygen as too much carbon monoxide. CO binds to red blood cells better than O2, and tends to stick around for a while (IANAC).
posted by yohko at 6:05 AM on April 27, 2007

Is it possible to relocate the water heater in an outside enclosure? If you are handy, it could almost be done for next to nothing. Maybe just the price of a few extension pipes which is cheaper than a CO detector.

If I were you I would not take the chance of living in the same room as a gas water heater.
posted by JJ86 at 6:14 AM on April 27, 2007

vented to the outside world - you won't die.

However, I would get a good CO2 monitor. For instance, what if the vent get clogged etc.?
posted by caddis at 6:55 AM on April 27, 2007

What paulsc and yohko said. The vent's proper function is contingent on a good supply of fresh air. We recently replaced all the furnaces in our condo complex, and the gas company required modifications on several of the installs to ensure adequate combustion air volume.
posted by Opposite George at 7:35 AM on April 27, 2007

Second, since CO is slightly lighter than air, keep your bed low.

CO is only about 3% lighter than air so there will not be significant stratification. CO2 and H2O mixed in the combustion products will make the exhaust heavier than air. I would just assume that CO will be fairly evenly distributed in a room by convection and diffusion.
posted by JackFlash at 8:59 AM on April 27, 2007

By the way, you mention that there is an opening between the top of the heater and the vent pipe. This collar shaped device is called a draft hood. It is actually a safety feature. When a strong gust blows on the roof in a certain way, it is possible for the wind to be forced down the vent. The back pressure could force combustion gases to enter the room directly from the burner at the bottom of the heater. To prevent this, the draft hood opening allows the back pressure from the wind to escape from the periphery of the vent while hot combustion gases continue to flow up the center of the vent.
posted by JackFlash at 9:15 AM on April 27, 2007

Under normal circumstances, the hot gases flow up the center of the vent and also suck in cold room air around the periphery of the hood, so there is no escape of combustion gases. You can test the proper function of the vent by waiting for the heater to come on, then hold an extinguished match or candle next to the draft hood and see if the smoke is drawn into the vent.
posted by JackFlash at 9:27 AM on April 27, 2007

Okay so; getting a CO detector and possibly a natural gas detector would mitigate my chances of dying, but I would still need a constant fresh air supply and I might still get low-levels of CO poisoning.
posted by beerbajay at 10:57 AM on April 27, 2007

If possible, replace the door with one that is vented, even if it's only temporary.
posted by blue_beetle at 11:42 AM on April 27, 2007

An interesting tip about where to place your CO monitor: In addition more than CO will be emitted with furnace failure or with the use of an unvented heaters. Carbon dioxide a heavier gas will collect on the floor building up and possibly preventing carbon monoxide from ever reaching the alarm if located at a floor outlet. That is why it is recommended that CO alarms be placed high around eye level where the
higher concentrations would be concentrated.
posted by caddis at 1:59 PM on April 27, 2007

I didn't die. I bought a Carbon Monoxide detector, and often left my window open. The heater didn't run much at night, but I was still super paranoid and it didn't feel good to live in the room.
posted by beerbajay at 6:08 AM on January 14