NG exhaust question

[ryan paulsen]

I'm going to have a NG unit heater installed in my garage sometime before winter. All of the units come with explicit instructions to have them installed by a licensed professional. My question is, why is a 60K btu heater more dangerous than if I turn on the 4 15K btu burners on my NG stove? Aren't the combustion products the same?

FWIW I'm not questioning the danger of CO from the heater, but more curious what the difference between the two is.

[Eduard Nemirovsky]

probably different rate of produce combustion from heater and stove. You are not using all four-five burners same time very often or probably never. Usually small space where heater located and wide open space in the kitchen?

And few more reason I don't know

Ed.

[Malcolm McLeod]

I suspect it has more to do with product liability concerns than anything. Either could fill a given space with CO/CO2 and no one wakes up, but most NG cook stoves do not run while people are asleep.

On the other hand, my grandparents heated their house for 50 years with multiple open-gas-flame heaters to no ill effect. (It was an old house and when the wind blew hard outside, it was just a gentle breeze inside.) I think that you installing heater in a garage with typical limited air seal on 'car' door will be similar.

[Michael Weber]

Your range has unlimited air to provide complete combustion. Air is restricted in a vented furnace for reasons of efficiency. A certified furnace SHOULD only produce low CO levels (typically around 400 ppm). But a badly adjusted furnace or one with a cracked combustion chamber can easily exceed deadly CO levels. So your answer is a stove has access to unrestricted oxygen while your furnace does not.

[Brian Elfert]

I've been told a gas stove should have a vent hood that exhausts outside. My house only had an electric stove when I moved in. I had a gas line installed as part of renovations and put in a gas/electric stove. I had someone come by to quote me on installing an exhaust line for a vent hood. He stated that code requires a outside exhaust for a gas stove. I guess they expect the cook to turn on the exhaust hood when using the stove to get rid of the combustion byproducts.

I was getting a quote for an exhaust line to remove steam and cooking odors. I didn't think about combustion byproducts.

[Lee Schierer]

My question is, why is a 60K btu heater more dangerous than if I turn on the 4 15K btu burners on my NG stove? Aren't the combustion products the same?

How many hours per day do you run your stove and how often do you run all four burners wide open? Maybe 1 hr total on one or two burners? How many hours per day will your 60K heater run? In an 8 hour work day maybe 4 hours. In 24 hours maybe 12 hours. Do the math?

[roger wiegand]

I suspect that the licensed professional language has more to do with piping gas than the exhaust. In many places gasfitting is the most tightly regulated of the trades-- in Missouri I could pull my own permits for plumbing and electric, but not gas. I the town I'm in now in MA of course all three are out of the question. I suspect that by code these must be hard piped, putting them into the realm of requiring permits and therefore a "licensed professional". When I installed mine the gas company wouldn't turn the gas on to the building until the inspector had signed the tag. It's all about not getting sued when the building blows up.

[Joe Tilson]

Just one question:
Why would you want an open flame where sawdust will be?

[ryan paulsen]

Thanks for the responses. I'm not even sure if the county will let me pull the permit myself or not, but wanted to check in here before I even considered it.

To answer some of the questions: The hard-piped gas as well as electrical are already in place. Also, I will be going with a unit that uses room air for combustion as opposed to a separate combustion chamber. My current stove does have an exterior venting range hood, but my old house just had a recirculating hood.