In their heater section they have ... ventless heaters. The biggest is a 30,000 btu. I was thinking of using a ventless for my 30x48 garage just to keep it above freezing. Then when I work in the shop maybe a 75K Reznor. The reason being that the ventless appear to be much more efficient. I would think it would cost a lot less to run that ventless all winter than it would a reznor that is only 82% efficient. Any thoughts? To avoid these ads, REGISTER NOW! ... I've gotta small infrared gas heater that ... More on garagejournal.com

I’m trying to figure out what ... or ventless? Is this an hvac install or does a plumber run the gas lines? Those of you who went through this install if you don’t mind me asking what unit you picked out and what labor costs ended up if you hired someone. Thanks! John You’ll need a gas guy to run the gas line but installing the heater is easy. I recommend the Hot Dawg Garage heater by moline. It’s perfect for that and comes ... More on golfsimulatorforum.com

They appear safe enough (blue flame usually means it’s outputting little to no CO) and of course install it per the instructions so it’s not at risk of tipping. I doubt whether moisture brought up by the other commenter would be much of an issue (over and above what would be there already in a Midwest winter). That said, whether this is the right heater for your space depends on what you’re wanting to get out of it. Aside from requiring a new gas line, the main consideration is that it’s a convection heater. So, it will heat the space relatively slowly and need to be operating most of the time via a thermostat. Contrast with an electric forced air heater like this one . This would heat the space quickly and be used mainly when you’re in the space. For example, turning it on 15 min before you’re ready to be in there, then letting it cycle on and off to maintain the set temp, then turning it off when you’re done for the day. We have one similar to this in a large garage/ceramics studio and use it in the way I’m describing, and we’ve been very happy with it and don’t have to worry about gas safety. The only downsides of the electric forced air heater are utility cost and noise. I wouldn’t say it’s loud but definitely would be more noticeable that the gas heater. Cost will depend on how big your space is, how often you’re using it and at what temp, and the price of gas in your area (probably cheaper than electricity, but also recognizing that the gas heater may be running more often than the electric one). There are also gas forced air heaters, which may be a good trade off. The other commenter mentioned one and here’s another example . These do require a vent, but that would probably reduce the safety (and moisture) concerns. More on reddit.com

I personally wouldn’t do something gas & non-vented. I know this is probably an unpopular opinion, but I’ve started to care more about what toxic things I’m breathing as I get older. The research about the long term health impacts of poorly vented gas appliances is not good. The research is mostly around stoves, but I can only imagine an unvented heater would be worse. I’d personally try to go for something electric. More on reddit.com