THE IMPACT OF THE OPERATION IS TWOFOLD, IN THE CASE OF A COGENERATION PLANT FOR COMBINED HEAT AND POWER PRODUCTION AND A TRIGENERATION PLANT FOR THE PRODUCTION OF ELECTRIC ENERGY AND HEAT, BOTH IN THE FORM OF HEAT AND CHILLED WATER. IN ADDITION TO THE COGENERATION PLANT, IN ADDITION TO THE COGENERATION PLANT, THE INTERVENTION SHOULD BE INTRODUCED ON THE BUILDING ENVELOPE THROUGH: THE THERMAL INSULATION OF THE WALLS, THE THERMAL INSULATION OF ROOF FLOORS, THE REMOVAL OF THERMAL BRIDGES, THE REPLACEMENT OF WINDOWS, THE SOLAI REVISION, ETC. FINALLY, IT ALSO PROVIDES FOR THE INSTALLATION OF A PHOTOVOLTAIC INSTALLATION AND THE REPLACEMENT OF THE WHOLE OF THE ILLUMINATING BODY FROM A LIGHTING SYSTEM WITH FLUORESCENT LAMPS TO A LIGHTING SYSTEM WITH LED LAMPS WITH ENERGY SAVINGS OF AROUND 60 %.