The article deals with the verification study of the heating gas apparatus ""IMMERGAS ""for heating and hot water supply systems by the method developed at the Department of"" heat and gas supply and ventilation ""DSTU in accordance with GOST 20219 – 74""heating Gas appliances with a water circuit."" The results of processing of the gas system installed in the property (residential building) Rostov – on –don, street 1 – I Kombinatskaya, building 2. The main attention is paid to the main indicators of the gas apparatus of the heating system in conjunction with the hot water supply. The main indicators are: efficiency (η), heat loss with exhaust gases (q2) and in the environment (q5), as well as the excess air ratio, which has a significant impact on the efficiency of the heating apparatus.

Keywords: heat balance, natural gas, efficiency, excess air ratio, heat of combustion, amount of heat, temperature, heat loss, heating