We use a synthetic domestic duvet instead of sleeping bags and have usually been warm enough when ice forms on the windows as we benefit from shared bodily warmth. However, we always travel with down sleeping bags in our rucksacks for use on side trips. We would be able to supplement the duvet if need arose.
As mentioned by someone already, I made thermal foil covers for the windows and have been known to sleep with the pop up down when very cold.
As for heaters running all night, I have entertained murderous thoughts when parked up near people ruining my sleep with climatisation units.
As mentioned by someone already, I made thermal foil covers for the windows and have been known to sleep with the pop up down when very cold.
As for heaters running all night, I have entertained murderous thoughts when parked up near people ruining my sleep with climatisation units.