The application of EN ISO 52016-1 to assess building cost-optimal energy performance levels in Italy

In Italy, the cost-optimisation calculation procedure, based on the comparative methodology framework established by the Commission Delegated Regulation 244/2012 to derive minimum energy performance requirements of buildings, was firstly applied by means of a monthly quasi-steady-state calculation method based on EN ISO 13790. The introduction of the new EN ISO 52016-1 simplified hourly calculation method determined the possibility of testing the new assessment procedure. The aim of this work is to analyse the deviation between the monthly and hourly calculation methods in the assessment of the building energy needs for space heating and cooling and in the selection of cost-optimal solutions. The cost-optimisation analysis was hence performed on a group of buildings representative of the Italian building stock. The results of the monthly and hourly methods in terms of cost-optimal levels and packages of energy efficiency measures were then compared. Results show limited variations in the resulting global cost, while differences in the cost-optimal packages of energy efficiency measures are not negligible. A sensitivity analysis of the main economic parameters was carried out, pointing out the main influencing factors.