Calculations of solar water collector hourly thermal energy output as part of central solar water heating system with individual 150 liters storage tanks for each apartment in high rise multi-apartment residential building in Tel Aviv. The energy output at noon is 758 kcal/hr in January and 1,221 kcal/hr in April. Solar collectors supply 2,647 kWh/year of thermal energy to each apartment, minimum 5.41 kWh/day on an average day in December, maximum 8.53 kWh/day in August. Hot water supply equivalent at 40°C is 30 liter/hr in December and 81 liter/hr in August at noon, 192 liter/day in January to 500 liter/day in August.