A theoretical analysis was performed to study the attenuation of a heat wave through five different walls. Each wall is made of three homogenous layers in addition to an insulation layer, all of which are made of local materials. The study included the effect of the thermal resistance of the insulation layer on the attenuation of the heat wave traveling through the walls, on the wall inside surface temperature and on the relative humidity inside the room. It was found that these three factors increase with the insulation layer thickness. Having selected the wall with the best thermal performance, the effect of the insulation layer location within this selected wall on the attenuation of the heat wave and on the inside surface temperature of the wall was also investigated. It was found that as the insulation layer approaches the inside surface of the wall, its thermal performance improves.