This is an option on new A'vans, but of course it can be retrofitted at any time. You do need to fit a 14 to 22 litre hot water service to get the most from it. (Suburban or Atwood etc.). A new Suburban model runs on gas and 240 volt. These are available from Camec or Caravan Accessories. Brian and Estelle Egan (Queensland A'vanners) have fitted an electric only model that works really well.

Bob Eustace