Here in Switzerland it is quite cold during the winter.
I do not know what is used for heating in the United States.
Here in Europe, the company is very common with the Truma Combi CP Plus.
When complete reconstruction unserers Airstream we have built a Truma Combi 4 CP Plus. With the display, the settings can be adjusted very comfortable.
The advantage of this heating is that of the hot water boiler is integrated in a single device