... only65% of the solar energy water heater,25% of electric water heater. When it is hot water and cold ... heat cyclely and automaticly. 7.Dual-core designHeat pump, electric auxiliary heat integration together, super energy-saving and hot ... 410A, no damage, environment friendly. 11.Multi-source designAir source , ground source, solar and electric auxiliary heat integrated together (optional), super energy, ...