PURPOSE: To save energy, by providing each of condominiums with an individual heat balancer that is equipped with a watt-hour meter and can be controlled by the involved tenant, and controlling individually the air condition of divided areas.

CONSTITUTION: Each heat belancer 6A is connected with a feeder 17 separated from both a power distributing wire of a centralized air conditioning facility 12 and a power system of the building, and the watt-hour meter 18 is connected with the feeder 17. The integrated value of the watt-hour meter 18 is sent to a centralized control board and a control board 19 of each condominium and is displayed. Each heat balancer 6A is controlled by the control board 19. In case when each tenant divides his room arbitrarily, the room is partitioned by a partition 11 having a temperature sensor 20, and the temperature sensor 20 is connected with the control board 19 and the centralized control board 16. In this case, the installment of the individual heat balancer is specified and the other heat balancers are controlled centrally. According to this arrangement, the energy required for the building as a whole is saved.