As part of its policy to combat global warming, the Department of Cantal is implementing the thermal renovation of its Hôtel de Département in Aurillac. This building with an area of 7,615 m2 was built 37 years ago (1987) and it does not meet current energy performance requirements. The objective is to achieve the BBC Effinergie level of 40% savings compared to the reference standard and energy class from D to A after work. The main thermal improvements concern both the building and the technical installations (change of heating mode and regulation, exterior joinery, glass roof, roof, LED relamping....)