Correlation between carbon dioxide concentration and condensation in homes.

Ventilation systems in dwellings should not only maintain the quality of the air, in other words limit pollutant concentration whatever the origin, but protect the structure, that is, limit condensation and the storage of excessive humidity in existing materials. Domestic ventilation represents a significant element of energy loss. It is a function that should be provided at minimum cost in terms of energy and therefore be directly dependent on fresh air requirements. Hence the introduction on the market af socalled hygro-adjustable ventilation systems. However, these systems do not necessarily meet air quality requirements and, at present, on the French market, there is no existing model of a ventilation system adapted to the residential sector and controlled by gaseous pollution content. To be able to offer dual heating/ventilation systems which meet air quality requirements, while remaining low on energy costs, the ADEME, GDF, EDF, FNB and CEBTP have combined their skills and capabilities in a research programme involving, first a national survey followed by in-situ measurements and, second, the development of a hygrothermal and ventilation code incorporating pollutant transfers i.e: the BILGA programme (FNB/CEBTP) . One application of the programme was to find out whether there was a correlation between carbon dioxide concentration (present in most pollutive productions) and condensation hazards in dwellings, making it possible to control ventilation on the basis of a single criterion and then examine various ventilation strategies. This study is currently in progress.