Today, nobody doubts that, just as we can parameterize a building, know how tall, how much you weigh (the famous question that Buckminster Fuller did to Norman Foster, "How much does your building weigh your, Mr. Foster?") today we should all know how much our buildings consume and what to do to improve their energy efficiency. In fact, our latest buildings are all "passive house" (buildings CERN match as specified by the RT-2012, strict French regulations and self CERN) and the last two reforms in Barcelona (buildings in Travesera it -amigo and the Diagonal 409, have obtained the Certificate LEED CS GOLD and energy rating Calener GT Level B, rehabilitation), something always more difficult than when raised in new buildings and can play with envelopes. Without going further ahead to make our buildings merit consideration GREEN BUILDING, in the Geoda building Travesera, they have designed the installations to allow a reduction of between 40 and 45% energy consumption of a building similar features and minimize carbon emissions.