A recommended purchase for winter camping is the two-part thermo mat from Fiamma. It extends over the entire front of the vehicle to the ground, there is no cold in the vehicle. The windows are no longer fogged up or damp in the morning. During the day you can open the upper part via velcro and enjoy the view into the nature or marvel at the fellow camper while working around.
The mat is bulky and heavy, but absolutely useful. It is quickly attached by two persons. The upper and lower parts are connected by velcro. In addition, the upper part can be secured on the handles of the passenger and driver doors. Furthermore, the lower part can be attached to the floor with pegs, the corresponding eyelets are available.
Once installed, it not only keeps out snow, cold and frost (as far as a transporter van can), but also saves the "wiping" the next morning, because the windows inside, if at all, only fog up minimally.
Conclusion: Expensive to buy and a bit bulky, but worth every cent in the long run.
Wynen Gas bottles can be refueled (LPG / Autogas) from the outside at certain filling stations. The bottles are connected to each other and filled simultaneously. The system has the great advantage that the gas bottles do not have to be exchanged. In addition, they have a manometer on which the filling level can be easily read. The consumption is thus immediately apparent. This is unbeatable, especially with winter camping, as you don't have to worry about the heating failing at night and you have to screw over the bottles when the temperature is below zero.
We had bought ourselves additionally an Inline gas filter, so that the lines do not rustle, nevertheless LPG is refueled.
In addition, we bought our own thread adapter to screw on the tank nozzle. Some petrol stations lend it, but not all.
Conclusion: With a good LPG filling station infrastructure, the system was the best choice for us. Especially in summer the gas consumption, e.g. for cooking and refrigerator operation, is very low. For example, during our 3 weeks holiday in Sardinia, we used about 50% of one bottle of gas (cooking in the morning and in the evening, always a cold beer at hand).
In winter, depending on the temperature, one bottle will last for about 3 days. Here you have to be aware that after about one week you have to go to a gas station with LPG gas.