*Furnace is rated at 35,000 btu..........that is total btus PER hour of use
*Water heater....6 gal. If Atwood/8800 btu & if Suburban/12,000 but----PER hour of use
*Stove top...1 high btu/9000 btu and 2 low btu/5000 btu each----ALL three on high would be 19,000 btu PER HOUR of use
*Oven....2000 btu PER hour of use
*Fridge....1200 to 2200 btu depending on size ----total PER hour of use
EVERYTHING Running....high use/70,200 btu PER total hour of use
1 gal of propane----91,000 btu
40# propane holds 9.4 gallons (80% liquid level)TIMES 2=====18.8 gallons
1,710,800 btu available------divided by 70,200 usage ======24 hrs of TOTAL usage
That would be roughly 4 days of burn time and with everything turned ON :B
Real world experience......we FTd for 7 yrs with TWO 30# cylinders
Water heater ON, fridge ON, cooked daily using stove top and oven
Summer time....avg. 6 weeks per cylinder
Winter time....furnace on---avg 4 weeks per cylinder using furnace at 65*F daytime/55*F nighttime
(One winter....-19*F one 30# cylinder per day OUCH!)
Propane is cheap...goes long way.
Two 40#....LOOOOOONG time