AbstractThere is a feasible case study of constructing some buildings free from fossil fuel in Iran. The proposed guideline is replacing of solar energy with different types of energies in a building such as electrical energy for lightening and cooling, energy obtained out of combustion of fuels for heating of building and so on. Regarding the high rate of energy consumption in our country for supplying of required cases of residential buildings, if it is possible to supply this type of energy from among limitless energy sources such as solar energy it is possible to have a considerable economy in fossil fuels. Some of the results of this research are parallel improvement of solar energy with economic development of Iran through real economy in costs and providing new job opportunities. Finally it is resulted that with regard to high rate of primary costs, there will be no more request for benefiting from solar energy, provided that we consider suitable subsidies for applying the solar equipment.