Vent free adds moisture to basement?

[FatttFire]

My younger brother is turning his basement into a rec room! He was going to put a vent free gas fire place in the basement, but a builder told him not to, because it adds moisture to the basement! So he isn't going to put one down there! Have any of you heard of this, is it true or just B.S.?

thanks,

J

 

[Highbeam]

When you burn a hydrocarbon such as LPG or NG with oxygen you will get carbon dioxide and water after combustion. That is what happens, the hydrogen in the "hydro"carbon turns into H20. You will also get a bit of unburnt hydrocarbon crap that is deadly but let's just not worry about that, oh and consuming the oxygen in the room isn't good for people who also like to breathe oxygen but lets not worry about that either.

Yes, water vapor will be added to the basement. Lots of water vapor and it will stink. Don't do it. Go with the direct vent if you must burn gas.

 

[Carl]

Very much so that an unvented propane or gas burner will produce lots of water as a by product of the combustion process. Freestanding construction
heaters are of this type and if you run them all day, shut down and come back the next day there is lots of moisture hanging from the rafters.

Many years ago we used a propane construction heater in a new construction home. We insulated the ceilings and put the required visqueen over it and when we went back the next
day the visqueen was sagging with pools of water in it and very soggy insulation. To remedy it we cut the visqueen full of holes to vent it.
At the time we couldn't figure out what caused it but years later I can see why it happened. Funny how we say
to do one thing and then find it is bad a few years later. I don't think they recommend visqueen on the ceilings or anywhere now. This was a totally
electric heated house and the visqueen was required at the time.

Soooo, an unvented heater may be ok to use a little and not have a humidifyer but if you don't want all that excess moisture, especially in a basement it would be best to
stear away from them and put in a vented one.

 

[Redox]

All sarcasm aside, many local codes ban them. They are not allowed in Baltimore City, but AFAIK all the counties around here allow them. In addition to the moisture they create, the risk of CO is very high. If you do install one, make sure you have a very good CO detector. The average basement is not very well ventilated and I guarantee that sucker will be making CO after a couple hours. And don't believe the hype about the "oxygen depletion sensor" they use. They will be making CO long before they snuff out that pilot light...

http://www.cpsc.gov/CPSCPUB/PUBS/463.html

Not in my house!