NOVELTY - The system has a feed that connects to outside air. A heat exchanger (7) is connected to a feed (3). A discharge (4) connects the heat exchanger and outside air. A channel connects the feed, the heat exchanger and the discharge. An impeller associated with the channel provides a volume flow of outside air sufficient for the heat exchanger through the feed and along or through the heat exchanger. The channel has a connecting pipe (9) between an ascent pipe (8) and a descent pipe (10). The heat exchanger is associated with the descent pipe.    USE - System for extracting heat from outside air installed in outer wall of building. Can also be used in roof of building.    ADVANTAGE - The necessary air feed through the channel is provided wholly or to a considerable extent on the basis of the operation of the heat exchanger when it is placed in the descent pipe. The cold air does after all tend to sink and so pushes the airflow downward through the descent pipe. Applying a large, heavy fan causing noise nuisance is avoided. The channel of the system is placed inside the building or even form an integral portion, or be arranged outside along the outer wall, without generating disturbing noise or raising aesthetic objections. The effectiveness is increased in order to enhance the through feed of air in the channel. The warm air does after all tend to rise and so pushes the airflow upward through the ascent pipe. The system is provided with a heat pump that is connected to the heat exchanger, so that the low-noise or even noise-free thermal supply can be realized for the heat pump to in order to enable effecting of the function. The temperature of the airflow can thus be increased over the whole length of the ascent pipe in order to increase the speed at which the airflow rises through the ascent pipe and increase the efficiency of the system. Thus it is possible for the heater to be associated with the whole length of the ascent pipe to optimize the speed. The heater in the form of a fuel cell is utilized so that the gas container is provided for containing a buffer supply of gas required by the fuel cell, thus the continuous functioning is ensured, even if gas supply is interrupted. The heat pumps operates with air, preferably outside air, as heat source to produce the thermal energy required to convert heat in extremely quiet manner, without the use of heavy, noisy fans.    DESCRIPTION OF DRAWING(S) - The drawings shows the schematic overview of the system for extracting heat from outside air installed in outer wall of building.    Feed (3)    Discharge (4)    Heat exchanger (7)    Ascent pipe (8)    Connecting pipe (9)    Descent pipe (10)