[Former StClairSailor]

Just in case you are traveling in frigid temps and due to inclement weather have to spend additional days at a campground, like we are. Here are some bits of information on propane usage.

1 gal. of propane weighs 4.2 lbs.
A 30 lb. tank holds 7 gallons of propane.
1 gal. of propane burns 100,000 BTUs per hour.
So for example: A 30,000 BTU propane furnace will burn 1/3 gallon per hour.

Now you can plug in your furnace size and calculate how long you can heat your rig before having to refill. Keep in mind using the stove or oven will reduce the heating time. (We're using the microwave.) lol