The existing stock of institutional buildings constructed before current thermal regulation codes is known to be high-energy consuming. To make energy savings, retrofitting solutions have to deal with important transformations of those buildings (e.g. envelope, energy systems) and with better-suited management solutions. Such technical solutions quite often neglect occupants' comfort. The present work aims to develop and implement an energy audit protocol to tackle simultaneously the questions of thermal comfort and energy efficiency for higher education buildings. Our transverse approach allowed us to achieve a complementary view of the building under examination, including its operating conditions. At any rate, capturing the full complexity of a building-system (building energy devices, management strategies, and occupancy and behaviours impacts) requires a broad perspective and points to the limits of key-in-hand audits and solutions.