Emergency backup heat, ventless vs direct vent

[Arky217]

Was thinking of a direct vent propane heater for emergency use during power outages,
but I'm wondering how a ventless heater would work out.

I tried a small Mr Heater in a small camper one time and the moisture output was unreal.

But I wonder how a ventless would work out just running only in the daytime
during a power outage for a space of about 600 sq.ft.

Has anyone tried a ventless for power outages and was the moisture a problem ?

Also, what is your opinion of a 'blue flame' ventless vs an infrared ventless ?

Thanks,
Arky

[OlJarhead]

I have a ventless in my cabin as a backup for when I'm not there or to help warm the place when I arrive and it's very cold.  It isn't recommended (or perhaps legal) for areas people live/sleep or so I'm told but I use mine and have no trouble with it.  As for moisture I live (have cabin) in a very dry climate so it isn't even a thought.

I also have a vented through the wall propane heater in my back room (enclosed and well insulated) and it works great.

If I were going to install as backup heater where I live and might use a lot (say in a power outage) I'd go with a vented just to be on the safe side.  Sure they are a lot more but I think they would be worth it for safety sake.