Annex 27 - domestic ventilation, occupant habits' influence on ventilation need.

The Annex 27 (A27), Evaluation and Demonstration of Domestic Ventilation Systems, is given a genaral introduction. The habits varys a lot between individuals, the dwellings are of various sizes with various numbers of occupants being at home for longer or shorter times. Those facts needed to be collected in the beginning of the annex. In this paper background data will be given to make it possible to discuss the varied need for outdoor air supply in dwellings. Data for the parameters have been collected from many sources. Often the original purposes of the studies were quite another than discussing the required outdoor air supply. Sometimes the sources can be found outside the research field of the built environment. Statistical data will be given on dwellings such as size, number, construction year, persons/dwelling, and also concerning the use of the dwelling and the occupants' habits. The variation can be over the duration of the building. For the short time variation we can find some sources on time spent in dwellings, shower habits, water consumption, cooking time, use of appliances in the dwelling, number of pot plants, window airing and smoking habits.