Ventless Gas Heaters

So, what’s the SD on ventless gas heaters as far as safety goes? We are considering one to heat a ground level area that was formerly for storage a but is now a sleeping/living area for a family member. Most, if not all, manufacturers say " not for sleeping areas". Are they really that dangerous assuming CO detectors are present? The heaters themselves have a low oxygen safety cutoff. I’ve stayed in several hunting camp type places that had one or more of these as the only source of heat and never gave it a second thought.

One thing to keep in mind: they are banned in Canada, California and parts of several other states.

If the Great White North doesn’t think they’re good for keep you toasty and safe, there’s a real problem.

Fine in a draughty hunting lodge; not so much in a modern insulated home.

They pump out a ton of moisture too. That can be a good thing if it’s drafty and a dry/cold climate, as bob++ said, but if it’s your primary heat source then I bet that’ll be way too much. I suspect the sleeping room restriction isn’t as much about carbon monoxide/dioxide as much as the dangers of it running with nobody keeping an eye on it. They don’t have the safety cutoffs you find on electric heaters in case something falls against it, so being aware while it’s operating is more important.

Also, CO detectors are not infallible, and do have a shelf life before they no longer function.

Had my furnace go out a few years ago, and I used one to keep myself and my pipes from freezing overnight until I could get it fixed, but I certainly wouldn’t do it on a regular basis. I see stories of space heaters gone bad all the time, so the whole time I had it on, I kept imagining the headline that I would get once someone discovered my dead body.

I’ve used a couple of them. A mud room and drafty laundry room. Never a problem. This is a drafty log cabin, though. YMMV.

CO is not a major part, it will give off more CO2 and consume O2. I would not want to trust my life to something that had only 1 safety. In a drafty space then maybe.

Thanks for the replies. We are looking at other options now.

Also banned across all organizations within US Army Europe.

Just to add, I got one for emergency heat, hated it, felt light headed, turned it off and returned it. as to why they can’t make a cost effective vented gas heater I have no idea, but they are often 3x the cost to start and go up fro there.

Direct vent heaters are quite easy to install on an exterior wall. They draw air from outside and exhaust the combustion products using a co-axial duct. I have two direct vent furnaces in my garages. They can be used with no electricity or you can add the circulating fan option. They can also be setup with a remote wall thermostat although you do have to purchase them that way it is not a conversions.


I’ve been using a 30K BTU ventless propane heater for several years now and I absolutely love it. It works when the power goes out. It’s way cheaper than an equivalent electric heater (first winter in my shed house I used two 1500W electric heaters and kept things fairly frigid in here and it bumped my electric bill up by $300/month–by contrast I use my 100 gallon propane tank for heating, cooking and heating water and I usually fill it twice to 2.5 times per year at a cost of about $300-350 per fillup) and while it does produce a fair amount of moisture that’s not necessarily a bad thing in winter. Too-dry heated air can lead to more susceptibility to colds and the like. If necessary I run a dehumidifier a couple hours a day, that keeps everything dry. The house is fairly tight and insulated although I did leave a small vent uncovered at one end of the house to draw in fresh air plus of course there’s a fair amount of air exchange from going in and out–I’m basically a dog butler. The house is under 500SF with a barn style roof so the ceiling is 11 feet at the highest point and I sleep in a loft. The heater keeps things toasty warm all day and I keep the thermostat set to around 65 or so, then I turn it off at night because I don’t sleep well in heat and in a loft of course everything heats up there first.

I have the one that produces blue flame but if you’re nervous about that there’s the infrared ones that are less scary. I like it, I don’t have a fireplace so that suffices in its stead.