This is a solution that is revolutionizing construction, especially in large cities, a system in which rooms are ventilated despite closed windows, thus effectively reducing excessive heat loss, while leaving polluted air outside. CMV or Controlled Mechanical Ventilation, physically exchanges indoor and outdoor air. Indoor air, which is often of bad quality, is sucked in by the system and deposited outside, while outside air is filtered and brought inside. The heart of the system is the heat exchanger which combined the two flows, allowing the internal air to release part of its heat to the incoming air before being expelled. The new clean air, from which most of the allergens and pollutants are eliminated thanks to special filters, is introduced into the rooms silently and imperceptibly through the diffusers. The system ensures clean and healthy air and while it can of course be installed on new buildings it can also be planned and added during the renovation phase by providing the necessary overall dimensions for the machine and pipes.