This ÖNORM specifies inspection procedures and optional measurement methods for the assessment of energy performance of existing boilers and heating systems. Boiler types covered by this standard are, boilers for heating, domestic hot water or both, gas and liquid or solid fuel (including biomass) fired boilers. Parts of heating systems covered by this standard are: boilers, including generation control, domestic hot water production facilities, heat distribution network, including associated components and controls, ¿heat emitters, including accessories and ¿space heating control system. This standard covers issues related to energy conservation and environmental performance.