Question about gas appliances and ventilation

You know how kitchen ranges used to have a stovepipe that went into the wall and vented outside? (And now, if you live in an old house, the holes for those pipes are sometimes covered with charming pie plate art.)

Why aren’t gas stoves vented anymore? Are they putting out less carbon monoxide than before? Or is it because modern stoves have range hoods?

The reason I ask is because some older friends of mine have a gas stove, a gas heater, and their carbon monoxide alarm keeps going off. They are kind of agoraphobic and dislike having strangers enter their home, but they’ve been having headaches and feeling ill, and I’m worried.

I switched from an electric to a gas stove when I remodeled my kitchen. Our local building code requires gas stoves to be vented to the outside – in my case, through a range hood.

Thank you, kunilou. That’s very useful information. Seems to me that with the appliances they have, there ought to be some ventilation.

The range hood is the usual option for this when you’re talking stoves and ovens.

My gas furnace has an exhaust vent that runs to the outside of the house. It’s actually runs for a long distance inside the garage with a special cup and tube to catch condensation and make sure it drips outside and not back into the furnace.

The gas water heater has the simplest vent - there’s a 5" diameter pipe as a heat shield and a 3" diameter pipe for the exhaust itself. They are in a 90-degree curve about a foot high and a foot long, going through the wall to vent outside. This is the only one that relies purely on draft for exhaust; there’s no fan involved.

Do they have a fireplace? I’ve heard that if people have a fire while keeping the rest of their house tightly sealed, then the draft created by the fireplace/chimney can sometimes pull air in through vents for gas appliances, bringing the CO along with it. It’s often recommend to open a window just a crack to make sure this doesn’t happen.

More specific to your friends’ situation… I don’t know that I could hear their story and then sit passively on a message board looking for advice. (Which I don’t mean as a criticism of you personally, just how seriously I’d take this kind of thing.) Calling 911 might be a little extreme… but maybe not. CO kills, and a CO alarm going off should be taken as seriously as a smoke alarm going off. The headaches prove it’s not a false alarm. If it was me, I wouldn’t sleep in that house again until a solution had been found.

dracoi: Thank you for your concern and the very detailed information; this will be very helpful to me if the best-case scenario involves me helping install some kind of ventilation device or whatever.

They actually did call emergency services the first time the alarm went off, but the folks who came out couldn’t find anything. (As my other friend points out, our friends had of course opened the windows when the alarm went off, so…)

We are trying to convince them to call the power company specifically to come out and check, because that’s their specialty and it’s free.

I just wondered what the deal was with stoves because you don’t really see those pipes hooked up anymore. Hell, MY apartment has a gas stove, an ugly plaster job covering the former pipe hole, and no range hood. So, you know, I don’t get why a landlord or house-seller would remove the pipe if the ventilation situation hasn’t changed. (i.e., no range hood.) It was there for a reason, right?

Fortunately, we keep windows open all the time for the cats. :dubious:

In the old days, gas stoves had pilot lights that burned constantly.* So they were effectively ‘on’ constantly, though at a low level. Presumably, that put out a higher level of Carbon Monoxide. Newer stoves have an electrical device that lights the gas when a burner is turned on, no constant pilot light.

  • Even older gas stoves required you to light the gas yourself when you turned on a burner – you could tell those by the box of wooden matches always located near the stove.

Oh, yeah, of course! That’s the difference. Thanks, ** . **

Ha ha, and wouldn’t you know, my gas stove does not have piezo-electric ignition. Guess we really should get a range hood too.

It’s good to hear that they did call out someone to take a look. I do hope they’ll aggressively pursue their options until the problem is discovered. Besides calling the utility, they might also have appliance/HVAC people come do inspections.

Going back to stoves… besides the absence of a pilot light in modern designs, I would think that there are also improvements in how completely the gas burns. In a perfect combustion scenario, you’d have no CO production at all - everything would be fully converted to CO2, which is relatively safer.

Your LP or Natural gas cooking stove/range is not vented.
Now that certainly does not mean that high levels of C0 aren’t possible if the stove is in need of cleaning.
New houses are much tighter than old ones and need air exchange units and that is commonly witnessed by condensate on the windows, on the inside of the house.
The old stove pipe openings are from the days of wood ranges or Gas Range with wood oven, and or the small wood or coal or Kerosene heating stove also called a garbage burner.
The Wood/Coal range I have in my cabin was converted to kerosene and I converted it back to wood.
I would look at the domestic heating unit for any high levels of C0 but a dirty gas range would be suspect. A range hood is for removing steam or smoke from the cooking process and will certainly remove C0 if there is any but is not always used.
And some of those units are not vented they only filter the smoke and such through charcoal filters and will not remove C0.
Any agency testing for C0 should know to test the air in the refrigerator as the air exchange is slow and entering the house will not adversely change the reading.

You stated that the alarm went off? do you know what kind of alarm it is and how old it is?
Does it have a readout on it?? get a new detector with a readout!
Could they be using the oven to assist in heating? Oven burners can get the
clogged with dust and spider webs and such especially if not used very often.
Almost all of those burners will come out very easily and its not hard to clean them by shacking out the rust and blowing out the dust and by inspecting the burner holes and cleaning if needed. of course the top burners can be cleaned likewise.

But check that heater unit!!

Wow, thanks, Gbro! I did not realize that a dirty gas stove will contribute to CO emissions.

From what you have told me, I gather that the assumption in an older house/apartment is that, because they are not nearly so airtight as newer construction, there will always be an airflow. That’s certainly true in my apartment (even with the windows closed) and I’m sure it’s true in my friends’ old house as well.

I don’t have any information about the CO detector, but they bought the house in, say, the last 5 or 7 years. What really has us worried is that, because it kept going off, they finally disconnected it. Needless to say, about the worst strategy ever.

That’s a great tip about checking the refrigerator air, I’ll be sure and pass that along.

I really appreciate everyone’s very pertinent advice. I promise that I’ll do my best to help them resolve it.