Solar Energy With Backup Gas – This system is preferred when required a domestic hot water and central heating system, and want to decrease cost and save energy. This system is consists of two sources of power: 1- Solar energy (primary heat source and main source for domestic hot water) 2- Gas boiler (secondary heat source and main source for central heating) And Smart Heat company activities central heating and heating central water and heating swimming pool and solar heaters, the first company in Egypt, a leading company in the supply Install the best Italian central heating by heating the water