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

Depending on your level of electronics hacking and how hard the manufacturer made it to alter, you should be able to control any furnace with your nest. The knobs you described are the thermostats in these units, you would just need to bypass what they're doing and reroute that signal through the nest. Best case scenario is you can find, and understand, a schematic for the unit you decide on. More on reddit.com

Won’t work. Those things don’t have 24v going to it. The only way would be going to the store and getting a 24v conversion kit. (Not 100% sure what it’s called). Basically you get the 24v because it plugs into a wall outlet and converts it there. Then you would wire it to the tstat More on reddit.com

you would need a hyperheat minisplit if you want a thermostat, otherwise it will need intervention to turn on and off. (this is the only way i am aware of without a central system modification)

More on reddit.com