Two commercial companies decided to support this initiative and donated solar heating panels. One company (AES Ltd) is the only Scottish manufacturer of flat plate solar water heating collectors. The other (Solar Twin Ltd) markets a Scottish invented system which uses a freeze-tolerant flat plate collector and a PV driven circulating pump. Both these panels(about 3m2area) were mounted on a hinged framework on a side of the van so they can be hinged out to face the sun. They are connected to a thermal storage tank (about 500litres) made of galvanised steel inside the van and insulated with polystyrene foam. The tank has an internal heat exchanger which allows fresh water to be heated before being delivered to a hot water tap and a shower. The hot water in the tank can also be circulated through an underfloor heater in the main room in the van. The underfloor heater is of a novel design which uses a flexible rubber EPDM pipe laid against an aluminium sheet located under the carpet. All the pumps are 12V direct current type. The van body is well insulated using wool from Scottish sheep so heat loss is quite low.