We quickly found that the furnace was noisy, intermittent, and the fan used way too much battery power when boondocking.
When we had an electrical hookup, we found that a small, cubic heater,
such as this, worked well and was quiet.
We now prefer the
Vornado AVH2 Vortex Electric Heater for even, quiet heat when we have an electrical hookup.
When we are doing non-hookup camping and expecting cold temperatures, we bring along
Mr. Heater Portable Buddy.
See how we use Mr. Heater Portable Buddy: "
Snug as a bug in a Safari".