English

This survey describes how external walls and joints are constructed in practice. The paper gives you an opportunity to compare how successful the implementation of airtightness has been in Sweden in comparison with the results presented in the report D2:1983 "Air infiltration control ..." by A Elmroth and P Levin. The survey covers the majority of all Swedish prefabricated single family houses constructed in 1984. All big prefabrication companies are included in the survey.

A reduction of infiltration and ventilation rates by a mere 1% would reduce annual US energy costs by about 300 million dollars. Infiltration and ventilation activities are an important part of the comprehensive energy conservation research policy of the US Department of Energy. The starting point for this policy is an analysis of how energy is used in buildings, starting with an examination of the buildings themselves. Summarizes US research and future activities.

This paper discusses the situation in the Netherlands with respect to air tightness of dwellings and reflects discussions about this in the Dutch Standard Committee on Air Tightness of Buildings. Results of measurements and calculations are given and the considerations of different groups in thediscussion are included. Finally an attempt is made to produce a model for the prediction of air flow rates, infiltration losses and seasonal gas consumption on the basis of air leakage measurements.

This paper reports a case study dealing with the relation between ventilating and airing behaviour and the outside climate. Also the significance of other variables such as preferences with respect to the indoor climate are considered. An indication is found that wind speed correlates, but outside temperature (varying from -3 to +9 degrees C) does not correlate with the length of time the windows in the bedrooms and bathrooms are opened. Rainfall and sunshine also seem to have some influence. The main reason for airing is the opinion that the bedrooms are too warm and not fresh.

Negative pressure inside a building may create adverse or dangerous conditions. Discusses when make-up air is necessary, how need is determined, and how much make-up, with examples.

Complaints related to moisture problems in houses which had been air sealed, led to a study of indoor air quality in 20 weatherized demonstration homes in the Cambridge, Ontario area. 

A previous paper analysed a mathematical model of a non-condensing cavity. This paper extends the analysis of the first paper to analyse the seasonal moisture behaviour of a condensing building cavity. Climate statistics are used to calculate the duration of the winter wet-up period, and a rate of condensation formula is integrated to give total winter condensation. Although engineering design calculations cannot yet be attempted, some illustrative examples are given based on field data. The results give preliminary verification of the model analysed in both papers.

This paper, the first of two, presents a conceptual model of moisture concentrations in a building cavity. The model is comprehensive and general considering air infiltration, vapour diffusion and material hygroscopicity under non-steady state conditions. The resulting linearised coupled differential equations are analytically solved to study the case of long term cavity moisture behaviour. Dimensionless parameters and algebraic formulae are presented describing all important moisture performance parameters for a non-condensing cavity.

Windbreaks probably are more important for reducing infiltration of cold outside air into houses than for reducing convective heat losses. It is difficult to estimate the magnitude of tree effects on energy use for space conditioning on a year-round basis, but past studies suggest that trees have the potential to reduce winter fuel consumption by 10-25%. Describes several studies of trees as windbreaks and for summer shade. Discusses location of trees with respect to buildings.