A prototype domestic solar water heater with an area of 1m2 was constructed and tested. The principal element was a simple shallow black tank insulated on the sides and bottom, functioning both as the collector and hot water storage tank. Cooling curves showed that adequate heat retention could only be achieved using a transparent cover consisting of monre than one layer. The amount of water in the tank was varied. With 50 L of water a temperature of 87°C was observed. It was concluded that it would be possi-ble to make a practical and cheap solar. water heater for equatorial regions by using In series 4 of the units tested.