Method for installing a heat exchanging device in a building

Method for installing a heat exchanging device in a building like e.g. a house, the device comprising a heat exchange module which is arranged for exchanging heat with the open air outside the building, the method comprising steps of (a) providing an opening in a roof of the building, (b) providing a housing having one or more air accession openings, the housing extending outside the roof and covering the roof opening (c) moving the heat exchange device or at least its heat exchange module, from the inside of the building towards the outside through the roof opening, causing that the heat exchange module mainly extends outside the building and is capable to exchange heat with the open air outside the building via the housing's air accession openings, and (d) fixing the heat exchange device or at least its heat exchange module to the roof, the roof opening, the housing or any other part of the building.