Will it be warn enough to caravan in January?

Hello

Have not slept in a caravan for 27 years...no heater then and Easter was the earliest we started. I remember cold feet!

New Lunar Quasar van, taking delivery in January,  Truma gas/electric ducted blown air heating.  Will it be warm enough to use as a base in winter weather? Our Son is moving then and there is a site very close, with electric points. My husband thinks it will be too cold, but surely many of you go skiing  and stay in your vans? Any comments, hints will be very helpful!