In order to reduce the heat loss from buildings it is common to increase the thickness of insulation in the building envelope.The consequence of this action is more expensive buildings. Building regulations in countries with cold climate require U-values far the envelope which results in thicker and therefore often stronger constructions than needed for structural capacity. Another strategy to save energy has been to reduce the ventilation rates in buildings.
New Zealand homes have traditionally been ventilated through open windows and by background infiltration. In recent times, new materials and construction practices have led to more airtight buildings, and open windows are seen more and more as a security risk. These trends call for new ventilation options that are inexpensive and consistent with home security, weathertightness and draught control. This paper is part one of a study of passive ventilation options for NZ homes.
The reason for the present project is the need for more reliable information about the actual ventilation conditions in naturally ventilated, detached houses. The aim has been to quantify the ventilation and humidity conditions and to establish a better basis for elaborating directions and guidelines on proper ventilation of detached houses. A national questionnaire survey covering more than 2100 households has been carried out, together with detailed investigations in about 150 houses.
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.
Blower Doors are used to measure the air tightness and air leakage of building envelopes. As existing dwellings in the United States are ventilated primarily through leaks in the building shell (i.e., infiltration) rather than by whole-house mechanical ventilation systems, quantification of airtightness data is critical in order to answer the following kinds of questions: What is the Construction Quality of the Building Envelope? Where are the Air Leakage Pathways? How Tight is the Building? How Much Ventilation Does the Air Leakage Supply?
The Dutch "E'novation" program is a national demonstration program in which dwellings with high energy consumption, moisture and mould problems and poor indoor air quality were renovated, with special attention to the selection of the heating and ventilation systems, thermal insulation and the buildings' physical details. A number of indoor air quality parameters were monitored before and after renovation, showing an important improvement in the indoor air quality. Moreover, total energy consumption decreased by 33%, which meets the targets of the Dutch National Environment Policy.
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