Winter months,what heating

hi there we are lucky enough to be able to keep our RV on the drive.it is hooked up to electric all the time and we leave a oil filled radiator on all the time with 2 tablet form de-humidifyers,this helps to keep it warm and dry when we are not using it.my question is what heaters if any do others use through the winter while their motorhome or caravan is not in use?

regards brian