The article presents the problem rationalising energy consumption in public buildings. Also it presents the structure of the energy balance in these buildings. Describes the steps that lead to the efficient use and energy consumption in public buildings. The most important of these are: use of an appropriate thermal insulation of building partitions, floors and roofs, insulating of windows, doors and partitions transparent, automation heating and ventilation systems of the building and partial or total building energy supply from renewable sources.