Thor Siesta, Citation etc Motorhomes on Sprinter chassis have a 20 gallon (85.2#)propane tank. They can only be filled to 80% of capacity or 68 pounds. (Overfill Protection) My propane generator uses about 2 pounds per hour, at half load (AC, Fridge, Inverter) or up to 3 GPH at full load (add microwave)
A 35000 btu furnace burns about 1.6 lbs/hour in actual operation. Even at 20 degrees my furnace is off considerably longer than it is on. Overall furnace propane consumption is very low.
U.S. Coast Guard retired- 1956-1985
2016 Siesta 24ST
1972 Moto Guzzi Eldorado