The Governmental Programme „Bringing your own house in order” was launched and implemented in Croatia over two years ago to improve energy efficiency in government-owned buildings. A significant number of buildings are under the protection of conservers either as individually protected building or as part of an entire protected old city centre. Approximately 2.375 buildings and office spaces are currently under revision. They are located on 2,21 mil square meters in more than 240 municipalities throughout Croatia. The buildings’ annual consumption is estimated at 60 million EUR. Extensive analysis has shown that protected buildings and buildings located within protected old city centres account for approximately 230 million kWh of the total yearly consumption, their emissions amount to 67 thousand tCO2, and they cost 14 million EUR per year. This paper elaborates on the energy performance of a specific group of buildings, and on their condition regarding the building envelope and the Heating, Ventilation and Air conditioning systems (HVAC). Furthermore, the energy efficiency measures that could be implemented take into account the buildings’ level of preservation. Although protected buildings are excluded from numerous regulations regarding energy efficiency, significant savings could be obtained by implementing specific energy efficiency measures, proper energy management and a change in the occupants’ behaviour.