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Are Vent-Free Alcohol Burners Safe?

Q: I have just finished reading your position on vent free gas products. I am also against any type of ventless gas fireplace. I cannot find much information on gel or bio-ethanol fireplaces. They are ventless and some are very attractive. What is your call on this type of fireplace system?

Jeff McQueen

Sweepy The fuel used in unvented alcohol fireplaces is liquid or gelled alcohol, usually ethanol or a blend of ethanol and methanol.

The good news: Most ethanol fuel products sold today are organic-based, distilled from fermented sugar found in grapes, corn, sugar cane, etc. This makes ethanol a renewable fuel, which gives it an environmental advantage over both natural gas and LP. Further, because ethanol is one of the the shortest alcohol molecules, much of the liberated energy is from hydrogen combustion: as a result, alcohol exhaust contains less C02 than natural gas or LP exhaust.

The bad news: Like natural gas and LP, ethanol reacts with oxygen during the combustion process to produce carbon dioxide and water, as well as trace quantities of other pollutants such as ozone, carbon monoxide, and nitric oxide. Although present at a somewhat reduced level, these gaseous poisons are still unhealthy to breathe, and in modern tight houses, could lead to the same resperitory, condensation and mold problems created by vent-free gas products.

The bottom line: Much is still not known about the long-term affects of exposure to even slightly accelerated levels of CO, CO2 and NO2 in the home breathing environment. If you opt for a gelled alcohol fireplace, it would be prudent to limit burn times, ventilate the area during use, and avoid any exposure of the elderly, pregnant, sick, or very young to the exhaust fumes.


To read about how much CO2 a vent-free fireplace exhausts into the breathing space, click here.

To read about a recent study of the effects of long-term exposure to CO gases, click here.

To read postings from vent-free gas exhaust exposure victims, click here.

To read a posting about vent-free gas appliances from an indoor air quality scientist, click here.

To read exerpts from a recent Consumer Reports article about vent-free fireplaces, click here.

To read letters in defense of vent-free products, click here.

To read our opinion about vent-free gas appliances, click here.

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