Vented propane heater

[ljamies1]

Does anyone have any experience/ thoughts on vented propane heaters? I have used the vent-less and wont do that again (found the condensation and fumes most unpleasant).

Currently have a 12ft and building a 30 ft yurt. Each will have a wood stove as a primary heat source. I was hoping to have some kind of backup heat option on a thermostat to keep both yurts above freezing.

Plan on leaving dogs alone in one of them and need to keep them warm and not worry about Carbon Monoxide poising.

I have no allegiance to the propane industry, open to any alternative suggestions as a back-up to wood.