The energy demand for heating in buildings in a residential area depends on the weather conditions of the area, the architectural characteristics and thermal-physical characteristics of the buildings, as well as the number of buildings in the settlement and the population of the settlement, accordingly. This study aimed to numerically determine the heat losses that may occur in case of different building materials (bricks, pumice, aerated concrete and briquettes) and insulation materials (XPS, EPS, rockwool and glass wool) used in the design of buildings, by applying the Finite Element Method (FEM) and considering the outdoor and indoor weather conditions proposed in Turkish Thermal Insulation Standard (TS 825). Then, the heating requirement according to the TS 825, the monthly fuel consumption, the payback period and the emission amounts in case of insulation were calculated for a model building with an external wall made of different building materials. In this study, the conditions of a model building located in Kahramanmaras/Turkey were discussed separately in terms of being thermally insulated and non-insulated. As a result of the analyses obtained by using FEM, the effect of the wall building material on heat losses was found to be much higher than that of insulation material. Following the application of thermal insulation to the non-insulated building model, it was seen that the payback period of the first investment value required for the insulation application varied between 0.25 and 1.74 years depending on the type of fuel used for the heating energy requirement as well as on the type of building material. In the case of using briquette wall in the building, it seemed that the heating requirements, monthly fuel consumption and emission amounts were higher than those with other building materials. The briquette wall was followed by bricks, pumice and aerated concrete, respectively.