This is a very negative trend in view of primary energy consumption, which is also proven in comparison with international studies. Newer buildings in Luxembourg consume more primary energy than older school buildings in other European countries (Fig. 11). European electricity consumption vary between 10 and 30 kWh/(m2a) (see [16-24]). In older school buildings abroad, lighting is usually the main consumer, whereas the more energy-efficient lighting used in the newer educational buildings in Luxembourg cannot compensate for the rising consumption of building equipment described above.