A novel design for an advanced solar water heater has been proposed. The design incorporates a double-sided flat plate absorber mounted on stationary concentrators. An experimental program is being undertaken to investigate the heat loss characteristics of the proposed design. The experimental rig is a full-scale model, located in a temperature-controlled room. Electric heaters have been used to simulate the absorber plate and thermocouples are used to measure the surface temperature on the heater plates as well as the ambient temperature. Low iron, anti-reflective glass, of the type used in a standard flat plate collector is used for the glass cover and the two concentrating reflectors have been modelled using aluminised reflective sheet. Heat loss measurements have been carried out over a range of heater temperatures from 30 to 100 °C. The overall heat transfer co-efficients obtained from the model are 30-70% lower than from conventional flat plate designs. The preliminary results indicate that considerable reductions in heat loss may be obtained with this design compared to conventional designs.