Why focus on mould, ventilation and health when thermally upgrading a house? Here are two of many reasons:
- Our population has the fourth highest incidence of asthma in the world and allergies are rising fast. Alarmingly things may be getting worse: recently the World Health Organisation has found that as many as third of Irish children now have asthma.
- Studies in other countries have found a close correlation between these diseases and the environments we spend so much of our time in: homes, offices and schools. In one study of 328 homes in southeast France, selected because residents had been admitted to hospital sick, Dr. André Charpin [1] and his colleagues found mould infestation in 44%, mite contamination in 32% and volatile organic compound (VOC) exposure in 9% of the homes.
The issue of houses contributing to the ill-health of their occupants is not to do with ‘airtight’ houses as some lobbies would say. We still probably have less than a hundred living units in the country where air infiltration has been reduced to 3 m³/m²h. The issue is hundreds of thousands of semi-leaky houses with no managed ventilation system, and little focus on moisture movement and the chemical constituents of building materials and furnishings. Ironically the houses of our great-grandparents which had gales blowing through them, roaring fires (giving good radiant heat) and a small range of natural building materials were healthier places than those we’ve been building for the last thirty years.
In contrast a well-insulated house with very low air infiltration (i.e. air leakage), good orientation and natural light, a well-design managed ventilation system, perhaps a radiant source of heat and a well-thought out palette of natural materials must be a healthy, healing place to live… as well as very energy efficient.
[1] Charpin-Kadouch, C., Charpin, D.A., et al (2006) ‘Housing and health counselling: Preliminary results of a new medical referral system in France’, Environmental Research
