A three collector, 120 gallon Velux solar hot water system was installed in the solar test home. Water in the solar storage tank is heated to 160 degrees using an antifreeze solution which circulates between the collectors on the roof and a heat exchanger installed inside the storage tank located in the garage. Domestic hot water is delivered at 120 degrees throughout the home summer and winter. Annually, this system generates 16 megawatts of free hot water using only sunlight.