I have one of these in my boat. It uses 2 litres in 24 hours and puts out an amazing ammount of heat. The only negative is the electric fuel pump 'ticks' so I would investigate the gas. It could easily warm up to an uncomfortable heat in Tassie winter and dry everything out.
I bought mine 10 years ago when they were introduced and I installed the unit itself and the supplier demanded that I use their installer in order to warrant installation and unit. There was no need. The installation is not difficult. I then installed one for a friend
I am taking the unit out of the boat and transferring it into a camper im building. (everything is being designed around the heater) When I investigated the suitability for a vehicle, there is endless information on European sites as they are fitted to ambulances and trucks. You can get heat exchanger type fittings for hot water as well.
There are 3 different brands that I found, of very similar look and performance. There is enough competition to lower price.
Good luck.

