Thermal confort accompanied with low energy in architecture is a major target of buildingresearchers and designers worldwide. Obviously, any portion of energy that can be saved in thisrespect means protection for environment and maintenance of its resources and may be able to bedirected to any other activities, if any.Building energy consumption can be reduced through various systems such as air conditioning (ACis a major building energy consumer), lighting, equipment, etc. In regions where energy is limited orscarce, air conditioning would have to be replaced by natural ventilation for the removal of thebuilding heat load for thermal comfort.Also, energy conservation issues are being more important in hot arid regions, especially becausebuilding are consuming more than 60% of electric energy generated and about 65% of this energy isconsumed for cooling. There is a set of complex factors, which determines energy needs in building,such as solar radiation, type of A/C systems, building operation, and thermal characteristics of thebuilding envelope …etc. The parameters, which have effects on the thermal performance of wallsand roofs, are the color, general construction, insulation and ventilation.In the present decade the aim is to discuss the meaning of thermal comfort and advantage of energyefficient building materials design or selection. There are several ways to reduce the energyconsumed in the human comfort process, but what is the most energy efficient or more energysaving of these ways. One of these is the insulation, which can be used for insulating walls androofs, which are subjected to a large amount of the solar heat gain. The insulation of walls(especially west walls) and roofs is intended to maximize resident’s thermal comfort and minimizeenergy consumption in housing.The present study presents the effect of west wall insulation on the indoor thermal performance inorder to select the suitable insulation which gives maximum thermal comfort , minimum cost andmaximum energy saving. This work was done using actual field temperature measurements onactual location. The results provide suggestions to improve the building construction and indicatethe importance of using the insulation materials in the wall construction in order to achieve thermalcomfort characteristics for the occupants and also to reduce the consumed energy.