As the temperature falls Ive been forced to use a heater. Electric, diesel, LPG, wood - they all have their issues. I'm really pleased with my small (about 50 Watt) solid fuel heater. 50 Watts isnt much but it does take the chill off a well-insulated van, and you can leave it on 24/7. Even stick it under the bedclothes to warm the bed up. I say solid fuel, the fuel is actually a sort of fatty goo that comes in tins. You feed it into the heater twice a day. The one I have also doubles a security device, makes a hell of a noise if anyone apart from me approaches the van. Overall one of the best bits of kit Ive fitted to the van. If you run out of the fuel it will also run on chips and cake in an emergency. Only negative so far is it does sometimes fart in the night.