Originally Posted by wincrasher
Is that rate just for heating, or for both heating and water heating?
Truma publishes gas consumption figures only for heating mode, but it's pretty easy to calculate the equivalent consumption for water heating:
Combi hot water capacity: 10 liters, 2.64 gal, 22.0 lbs
BTUs to heat full tank from 15degC to 40degC (140F): 1760 BTU
Propane energy content: 91,500 BTU / gal
Combi burner efficiency: 90% med / 85% high (boost mode water heating)
So in normal (med) water heating mode it will consume 0.0214 gallons of propane to completely heat the 10 liter water tank to 140F. Boost mode consumes a bit more at 0.0263 gal propane to heat the full water tank.
Stated another way, a gallon of propane will heat the water tank from cold to hot (high position) about 46 times. That's really efficient compared to traditional open-combustion RV water heaters!