The difference between the average room air temp. and the air temp. a few cm above the room floor is added, as a measure for the ventilation heat loss. These sums are counted continuously or in regular pulse intervals as degree hours. These results are read out and in certain cases deleted. The degree hours result, for the computation, multiplied with the associated room constants: a) e.g. KW normal heat requirement, or b) in KW heater normal output, c) pref. in m<2> ground area. The share of the entire heat consumption is allocated and the heating costs are distributed according to the sum of all individual parts, or groups or dwellings.