The Aqua Hot has a Webasto burner in it,in a Liberty there is a 20 gallon domestic water heater that has a heat exchanger in it.the water in the hot water can be heated by 110 volt electricity,or the Webasto or the Detroit Diesel.The Webasto also has heat exchangers with thermostats in the coach and also in the water bay with thermostats to prevent freezing if you are in very cold weather.I think that both systems work very well,when parked the Liberty does not need the webasto for domestic hot water therefore it does not burn any diesel,but on cold days both the Webasto or the Aqua Hot would normally be running to heat the interior of the coach.