In modern conditions the special attention should be given to the automated climatic systems with a view of energy saving. In this work processes of non-stationary heat exchange in the room served by automated climatic systems are considered. Modern methods of calculation of a thermal mode of a room are stated. The interrelation between separate parameters of thermal stability of a room and automatic control of microclimate providing systems is investigated. Expression for calculation of controller gain is received. The end result is defined on the basis of receiving the approximate technique, allowing estimating the influence of a controller operating mode on total energy consumption by microclimate providing systems. This technique has a quite simple appearance and at further development allows development of engineering recommendations about the selection of optimum option of a controller operating mode for the engineering equipment. The statement is illustrated with numerical calculations by means of the created computer program and graphic examples.