Solar Water Heater Tank

1kWh of heat energy can heat about 30 Litres 7.5 US gallons of water up from cold to showering temperature. A household of 5 people will use between 10-15kWh of energy each day to heat water (not including space heating). In the winter more energy is needed to heat water as the cold water is colder, and people often have longer and hotter showers than in the summer. Water is normally heated by electricity or gas, but solar can be used to offset between 60-80% of this energy.