The problem with the furnace is that it draws a lot of power -- we do a lot of boondocking and have to conserve batteries, especially in cold weather. Yes, we could run the generator more than we do, but we do not like the noise, even though it is a Honda 2000. And the furnace is noisy, too.
The goal here is for some nice, quiet, radiant heat during and after dinner -- just to take the chill off the interior. (We could use a portable propane heater but I am a little concerned about carbon monoxide.) We are fine without any heat when it is in the 50s inside -- but when it drops below 50, even with a lot of clothing, it can get a little chilly. We usually sit inside and read in the evenings when we are camping in cold weather -- below 40 outside. We don't sit by the fire because we almost never make fires -- too much chance of a forest fire in the tinder-dry forests of the Far West.
We run the water heater very sparingly -- we turn it on in the evening to shower, and then off. So this would mean that it would be on for a somewhat longer time -- it would go through a few more cycles. But we would not leave it on at night. I'd be surprised if the pressure valve popped -- it never has. (I have tested it -- it does work.)
