There are many reasons to justify the improvement in the insulation of buildings. Even so, it is often followed as an expensive and difficult to repay compared to the improvement of active air conditioning systems. In order to correctly assess the convenience of improving the insulation of a building, it is necessary to take into account the opportunity (to take advantage of a façade or roof rehabilitation to carry out the action) and the term. If long-term actions are done, isolating the building is one of the first options, since the first thing to do is reduce the demand and then improve the way to meet this demand.
