"Is there a problem with ventless gas fireplaces?"
Column #876 12/10/11
On The Level
Q. Iíve been a reader of your articles for many years and I have never seen my issue and problem addressed. Iíd really like your advice. I love my gas fireplace. I use it every evening in the cold weather. My walls and ceiling became covered with soot over the years. I just had everything painted. Do I have to give up my evenings by the fire? Someone told me these fireplaces are outlawed in 22 states. Is this true? If so, why?
A. The type of gas fireplace you have is called a ventless gas device which simply means there is no flue to carry the products of combustion out of the house. They are identified for intermittent use which means they are not intended for burning 24/7.
Back in the early days when rules were being formulated for the installation and venting of various gas burning devices houses were known to be leaky and experiencing natural air changes per hour regularly in excess of four. Remember, there was a time when we illuminated our homes with gas lights. When I started the standard rule was anything burning gas intermittently 44,000 Btus or less did not require direct venting.
The soot you see accumulating on the ceiling and walls are-- and you seem to know-- visible products of your fireplaceís gas consumption. For me, whatís worse are the products of combustion you canít see and thatís carbon monoxide, water vapor and nitrogen dioxide. Carbon monoxide is called the silent killer because you canít see or smell it and in concentrations that arenít relatively that high are toxic to the point of lethal.
In older homes the natural air leakage kept places safe but after the first Arab Oil Embargo in the early 1970s this country went on a energy saving crusade and the rule was insulate, caulk and seal homes as tight as possible to hold in heat. The effort had the unintended consequence of holding anything else in the air along with heat and that included pollutants from unvented gas burning generated in the building. Trouble ensued and we called it the sick building syndrome. Unvented gas appliances such as fireplaces came in for close scrutiny. Many gas fireplaces come with oxygen depletion sensors should they over use the roomís supply but for me thatís really not where the problem lies.
Letís talk about where there are unvented gas fireplace restrictions. The entire country of Canada bans them. Minnesota and California ban them. Wisconsin bans them in homes built after 1980. Beyond that there about 25 states in which there are local jurisdictions that limit their use. Perceiving liability issues, many big homebuilders shy away from using them.
In Chicago a few years ago the widespread use of gas for heating, cooking and water heating plus the mounting reported carbon-monoxide poisonings in the city during the colder months prompted the Chicago Fire Department to require carbon monoxide detectors. The first Thanksgiving after the rule went into effect there was a natural temperature inversion over the city trapping a cloud of CO from all the ovens cooking turkeys and CO detector alarms went off all over the place. The fire department had to respond to the calls and it was temporarily bedlam. The result was they upped the CO threshold level of the alarms.
You should have a CO detector-- at least one-- in your house if you have a gas fireplace-- vented or otherwise. For that matter, if you have gas or oil heat, a gas stove, gas or oil water heater or an attached garage you should have a CO detector. Many security systems include CO detection as part of their service. I like those with a digital read-out so you can see what, if any, background CO levels you have. I have come to learn that even small levels of CO are not good for people or pets so the lower the levels the better.
There is a product on the market I like that looks just like a gas fireplace but itís electric. They are so realistic that they have fooled me. I was inspecting a new condo unit with gas cooking, heat, water heating and a fireplace with a glass front that looked and operated like a gas fireplace. I counted the gas lines coming off the manifold in the utility room and asked the construction superintendent where the fourth line was for the fireplace. He laughed at me and told me it was electric. Fooled me.
Iím not telling you to not use your unvented gas fireplace but use it sparingly. And be sure to shut it off before you go to bed.
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