Selection the best external wall of buildings for energy saving by AHP technique

Nowadays, with reduction of groundwater resources and increase price of these resources in the world, saving in these resources is necessary. Developed countries and some developing countries including our country is using other energy resources such as water, wind, solar and nuclear energy, however, due to inadequacy these resource in satisfying country's needs, still underground sources of energy are very important. Therefore efforts for saving in using these energy resources is the best action to delay, finishing of these sources, moreover, using of new technologies for efficiency using of energy. Residential homes are one of the places where a large portion of energy is consumed. Therefore, the article firstly four outer walls of buildings considered that the thermal insulation within the walls is built. Then criteria for evaluating these alternatives have selected through the study of literature. Finally, questionnaires distributed between10 building engineers and from the results of these questionnaires used to select the best substitute for external wall as for the energy saving.