Other building characteristics were also analyzed. The year of construction, an indication for thermal end energy consumption, is one of them. Almost all schools which were constructed after 2005 consume less than 100 kWh/(m2a) and often less than 50 kWh/(m2a) of thermal energy. The linear correlation [8], which is a measure of linear dependence between heat consumption and the year of construction, is negative (newer buildings consume less thermal energy) and a very high confidence level was determined, indicating a high probability that both values correlate (see Section 4 and Table 2). An explanation for the decrease in thermal end energy consumption after 2005 is that a new regulation "Fonds pour la protection de l'Environnement" [9] became effective.