Journal article: In the European Union, Energy Performance Certificates (EPCs) provide potential buyers or tenants with information on a property's energy performance. By mitigating informational asymmetries on real estate markets, the conventional wisdom is that they will reduce energy use, increase energy-efficiency investments, and improve social welfare. We develop a model that partly contradicts these predictions. Although EPCs always improve social welfare in the absence of market failures other than asymmetric information, their impact on energy use and investments is ambiguous and depends both on the time horizon considered and the distribution of energy needs in the population. This implies that, in a second-best world where energy externalities are under-priced, EPCs can damage social welfare.