I'm after a kombi but have young kids and am concerned about needing heat in the back. I'm aware vehicles are available with heaters (saw one today and the heater was good) but they are thin on the ground and I see a lot of people doing convertions actually remove them. If I bought a van without a heater and fitted a diesel night heater (eberspacher etc) could that heater also be used for extra heat when driving or is it stationery use only?