RV Furnace in a 5vr will be 35,000 btu
They LOVE propane and run exclusively on 12V DC
Either supplied by batteries or via AC Power thru converter.
Rule of thumb..one battery/one night of RV Furnace use then battery would NEED recharged.
Propane......
1# propane is 21,600 btu
30# cylinder------648,000 btu divided by 35,000 equals 18.5 hrs of furnace total run time
(we used a 30# daily when in -19*F temps)
RV Furnace use is necessary in cold weather for 'ducted/heated underbelly'
Space heaters OK for supplemented area heating
12V and 120V tank heaters....
Need AC power or if 12V then need recharging capabilities daily
OK if on electric hookup site.
Boondocking......can limit amount of propane used for furnace but still need generator or larger solar set up for maintaining battery
