The research aims to reach fuel conservation opportunities and environment Protection while heating the water, by comparing the most common uses of primary and secondary energy carriers in our country . For example, water heating using electricity generated by fuel oil and gas, or the direct use of gas and diesel oil for water heating. The coast of heating the water domestic uses was calculated by various ways, in order to find a low coast method and to avoid environmental damage. In this research ,the conservation of primary energy for water heating while using gas and diesel oil boilers, was 4 times larger compared to the use of electricity generated by gas and fuel oil .As a result, the coast of water heating using gas burner was 4 times lower, while the coast of water heating using gas boiler was 10 times lower, compared to the coast of electricity heating method. this research also showed, that the use of gas fuel , is the best water heating method, concerning fuel conservation and environment Protection.