The factors affecting the non-diffusing of the solar water heaters (SWH) in Iran has been inspected in this research. The energy audit implies that the efficiency of SWH convertors during cold period is not satisfactory and they need backup systems. A survey from users, experts, and suppliers of SWH reveals that the low price of energy carriers, low efficiency during cold period, un-reliability, water pipes freeze problem, non-economic, repair and maintenance issue, and high electrical energy consumption have been the main factors for non-widespread application of SWH in Iran. The financial consideration show that SWH are not economical, so the increase of the energy carriers prices up to their world values is the main factor and prior to the complementary solutions for developing the domestic applications of solar water heaters in Iran.