I used a paraffin heater for a while, the location I was in meant it was impossible to use electric. It was reasonably effective, but the van I had at the time was pretty drafty(!), so it needed to be positioned very close to the pump. Others have mentioned that your van gets all sooty, but if this happens, it is because the flame isn't set right, if it is, there will be virtually no smoke. Others have mentioned the smell and unfortunately this is definitely the case!, so if at all possible, an electric cable out to the van is the best way to go.