Camped out for five nights this November. Well below freezing every night. Had a generator going all night and used a 800 watt heater. The furnace was set at 70 degrees. burnt up 25 pounds of propane. I generally weigh my tanks so I know how much fuel I have. In Canada the tanks have to be re-valved every 10 years. A new expiry date is stamped on the neck.
I wonder if your propane was in fact mostly butane. Butane stops evaporating when it gets cold.
Also when you get liquid propane on you hand that is not a burn, that is instant frost bit.
