Recently purchased a 2017 Winnebago 31BE. How long could I expect my propane tank to last under these conditions; slide pulled in, small electric heater running, temp, 29 to 40, out in the open, heat...
Going from a ‘reverse engineering’ point of view, spec sheet says your Winnie has an 18 gallon tank, if your gauge is even roughly close, and assuming it really was full, you’ve used about 13 gallons. Winnie also lists your furnace as being a 32k BTU input unit. Propane is about 91k BTU per gallon.
So 13 gallons times 91k is about 1.2 million BTU, or about 37.5 hours of furnace run time, that’s about 7.5 hours a day for 5 days.