I have a natural gas stove and oven. Apparently someone thought that the byproducts of burned natural gas were safe enough for me to turn on my oven and four burners with no extra ventilation.
Why does my furnace and my hot water heater have a flue that goes to my roof?
The Master speaks. Short answer - your stove burns a lot less gas than your furnace, so doesn’t require dedicated venting.
I don’t know for sure, but I suspect it’s because stoves and ovens are typically not burning huge volumes of gas for long periods of time, so their by-products can be dissipated and diluted in the house air without harm.
However, a furnace is likely to burn a lot more gas a lot more often, and at that level, the byproducts could be harmful, so they vent them outside.
Besides
FYI: Many modern furnaces are so efficient that they don’t need a traditional flue. My new furnace has a couple of plastic pipes that exit from an outside wall. One is for fresh air intake and the other is for exhaust. The combustion is so complete and the heat extracted so well that water, a byproduct of combustion, needs to be drained away very similar to the air conditioning system dripping water.
My somewhat old gas water heater still uses a flue. Possibly a newer one won’t.
Thanks. I guess I should have looked there.
I have noticed a lot of gas (NG or Propane) single room heaters and also fireplace inserts are ventless (they vent into the room) and many have a oxygen sensor to shut down if low O2 levels are detected.
A furnace may just burn too much,though why not a gas water heater (the tank kind, not the instant hot water kind), that’s just basically a stove burner, or at least that’s how it looks
Gas water heaters are vented, even the new ones. My tankless water heater, installed two years ago, vents through an adjacent wall. I’ve never seen a gas fireplace insert that isn’t vented through the existing chimney or through the wall. A gas fireplace is nothing more than a furnace in your living room.
I do not know where you are but definitely not in Spain where the kitchen would be required by code to have two vents, one at floor level and one at ceiling level. My guess is this is the same in every advanced country. Plus, every kitchen I have ever used has a hood vented to the outside.
If you are cooking with gas in a small, non-vented kitchen you will very soon feel the air gets very uncomfortable to breathe. I know because I have experienced it in China. There they just open the window but if you keep it closed you can feel the air is not good for breathing.
And, as has been explained, a water heater or furnace burns much more gas and oxygen than a cooking stove. A water heater or a furnace would burn all the oxygen in a small kitchen in no time.
agree that a stove will produce a lower amount, if used just for cooking. with the air exchanges required for a dwelling it is OK. people that leave it on for heating have died, cooked their goose.
i’ve been in a small place that had a single gas space heater in the center; think about 4 ovens worth of burners turned all the way up. it was vented into a vertical flue.
What? I’ve lived in the US for 30 years. Never seen such a thing.
Well, after this thread, I did a little research. A standard Natural Gas (NG) stove can actually burn a bit more than a typical NG water heater. But most people don’t use the stove’s full capacity very often or for very long. I assume that is the difference.
Possibly not true, depending on whether you consider the US to be an “advanced country.” I’ve never seen kitchens with floor and ceiling vents - only the vented stove hood, which is used more for smoke and not gas fumes.
By the way, I have a gas fireplace with fake wood logs, and it’s made to be used with the flue closed, so that all the heat stays in the house. It has a built-in oxygen detector that shuts itself off if the oxygen levels get low.
It’s commonplace in Europe to have on-demand gas water heaters near the end use points such as kitchens and bathrooms. Between a gas stove and these heaters, the CO2 hazard is significantly higher.
And when they do, anybody with a brain turns on the exhaust fan above the stove. It may not exhaust to the outside in some cases (stupid, in my opinion), but it will at least provide air movement.
I’ve had personal experience with people being poisoned by CO2. In one case, it was in Portugal, where someone had removed a section of the exhaust duct from an on-demand water heater, which was venting into the house. Luckily, they only had symptoms such as headaches and nausea and nobody died. In Anchorage, people die every winter because they block the fresh air vents into the garage, thinking to conserve heat. Any flue gases that may escape venting from the boiler then collect in the garage, and then leak into the home. This is why annual boiler/furnace maintenance is critical.
I think that would be CO, carbon monoxide. My understanding is that your brain detects too much CO2 and gives you that suffocating feeling.
I recall a story several years ago here in Dallas where a worker was killed in a trench that filled with argon gas - the trouble is that since CO2 never built up in his blood, he didn’t realize that he didn’t have enough oxygen and just went to sleep.
Water heaters are always vented to the outside. I cannot imagine anywhere where it would be permitted by the building code to not vent the combustion gasses out.
In China I have seen very small water heaters (<5 l/m) not vented outside but, again, they have the good habit of having the window open wide.
Same here,even in high end gas ovens bordering commercial but made for homes, they are not vented, just expelled into the room.
Additionally most stove vents are used more for smoke and grease then to vent combustion products. And quite a many of them don’t vent outside, but just pass smoke through a charcoal filter then back into the kitchen. Electric stoves also have them, so the seem to be for smoke more then exhaust.
By the way, it is close to impossible to buy a gas oven any more in Spain and I expect it is the same in the rest of western Europe. The old ranges with an oven in front and burners on top have pretty much disappeared and now you get a stovetop integrated into the countertop and a separate oven which most often goes at eye level and is always electric so there is no issue with exhaust gasses.
Which would be fine if it were not for the fact that electricity is considerably more expensive than gas.
And all these new kitchens with everything built-in look fine but when something breaks down it is a major headache and expense.
(I just learnt that in UK they call the stovetop a “hob”. Gas hobs, Electric hobs.)
Of course. :smack:
I wasn’t asserting that they aren’t. I was saying that the danger of having additional gases is present when you have a source like a gas-fired water heater in your kitchen, so it makes sense to have vents such as the ones that you described.