The most appropriate energy performance indicator is the primary energy consumption (PE), as it takes into account in one single indicator the final energy consumption of the building as well as the energy losses in generation and transport.

According to the CEN (Comité Européen de Normalisation) standards with the terms set forth in the Directive, the energy performance has to be represented by a global indicator representing the weighted sum of energy delivered per energy source. This indicator can be based on:
a) Primary energy
b) CO2 emissions
c) Total energy costs
The Display™ poster refers to a) and b).