As the Alde heating system can be tailored to any type of vehicle, the system has to endure operation in a wide variety of conditions. If the fresh water tanks in your vehicle are placed in a compartment that is not warmed up during winter, you should drain the water system when the degrees start to drop to avoid freeze damage.
What about your heating system then? The Alde heating system operates with full capacity also during the winter months, even without fresh water in the water heater. Just empty the fresh water tank and water heater, drain the water system completely and then continue to enjoy those crisp winter days in a warm and toasty caravan. Business as usual.