Hiya.
If u check my page on facebook, search for;
nathanswindowcleaningservices
My page should come up. Ive posted a video of my system for my customers to watch, when I switched 7mnths ago. I filter thru RO n 40"inch DI into a 500litres tank. All in van. I use maybe 300litre max in day. So most nights run water through to keep it at 500l. Again from purefreedom. Happh with it, but worth investing in carbon poles and a good light brush!! Not part of their kit, you will regret it! My ro is a 450litre a day.
My van is fibreglass fitted, ive insulated the tank and filters as well. If gets too cold, ie have snow. I will run a fan heater in back whilst having breakfast, so maybe and hr b4 I start work.