Abstract: A building where the window openings in the facade and/or ceiling are provided with two spaced apart window panes at least one of which has the property of absorbing sun-heat radiation and between which air is allowed to pass, said building being provided with an air and heat circulation system comprising a combination of two different air duct systems. One system comprises at least one closed channel system for circulating air absorbing the heat from the window, which system includes spaces between the window panes and, in the walls, floor and/or ceiling, channels communicating with said spaces. In this system the air is brought to circulate at a speed depending on the desired room temperature. The other system includes a special channel system connected to the rooms for supplying intake air to said rooms. In this system the air is brought to circulate at a speed determined by the desired room ventilation.