Hello Tango, glad that you have found the forum at the new website and can continue to have the support of fellow owners of our unique vans.
You have one of those rare blue ones – we only know of a few here in the UK.
Barry, our webmaster has provided excellent technical advice as usual.
As you intend to ski – serious winter conditions, then probably you will be on EHU ( electrical hook up), so possibly you will use an electric heater for warmth.
The Exsis is well designed for winter use with all pipes located externally, but the large boot area and boiler will not really benefit from an internal electric heater. I would advise that you also use the gas heater system at times which distributes heat by ducted pipes into all those cold areas ( boot storage area and water tank). I would also use the separate hot water boiler to maintain a minimum temperature at least even if you are not using hot water ( perhaps boiling a kettle for drinks and washing up and using on site washing/ shower facilities)
Do you have an external cover for the windscreen and perhaps an insulated cover that you can lay over the black shelf internally over the engine bay – they will help to keep you cosy.
Enjoy your adventures
Fred