The technical specification provides data and methods for evaluating: the energy need for hot water production, systems efficiencies and primary energy need for space heating and hot water production, primary energy need for ventilation, primary energy need for lighting of non-residential buildings. The technical specification applies to newly design systems, retrofitting or to existing systems - for heating only - mixed or combined heating and domestic hot water - for producing only hot water, for ventilation only systems, for combined ventilation and space heating systems, for lighting systems in non-residential buildings.