PURPOSE:To provide a heating system for green house, etc., composed of a chamber having heat-accumulation function such as green house, a heat pump, a heat-exchanger and a heat-accumulation water tank, capable of easily controlling the temperature in the chamber independent of the weather and the time in a day and stably producing vegetables, etc., at a low cost by the use of midnight electric power. CONSTITUTION:A chamber having heat-accumulation function, e.g. green house 1 is furnished with an air-controlling system composed of a heat-pump 6, heat- exchangers consisting of a water-air heat-exchanger 2 for the green house and refrigerant-air heat-exchangers 4, 5 for outer air and two kinds of heat- accumulation water tanks 3 for hot water and chilled water. When air in the green house 1 is sufficiently high in daytime, heat is accumulated in the heat- accumulation water tank 3 by the water-air heat-exchanger 2. When air in the green house 1 is not sufficiently warmed by bad weather, e.g. rainy weather, heat is collected from outer atmosphere with the heat pump 6 via the refrigerant-air heat-exchangers 4, 5 and is accumulated in the heat-accumulation water tank 3. In the nighttime, the green house is heated by the water-air heat- exchanger 2 or the heat-pump 6.
