Energy performance certificates in the USA and in France—a case study of multifamily housing

In the USA and the European Union, buildings account for more than 40% of total energy use and a large proportion of buildings are energy inefficient. Countries address these inefficiency challenges with various initiatives and strategies. One of them relies on rating buildings with energy performance certificates, with the goal that awareness on energy consumption would lead to an efficient retrofit. In this article, we analyze the different methods chosen by the USA and France to rate multifamily buildings, i.e., the Energy Star score and the Diagnostic de Performance Energétique. We conduct a case study of a multifamily housing using a Design of Experiments to determine what inputs are the most influent on the output. In the French certificate, the results show that the climate, ventilation system, and building envelope are the most influent inputs on the energy consumption. In the USA certificate, the actual energy consumption and the climate are the most influent factors on the building score. We then discuss the significant differences in the two approaches, and the consequences in terms of accuracy, as well as how the DPE and ES scores are used as a tool in public energy policy to propose energy conservation measures and reduce energy consumption.