House-dust mite allergen concentrations (Der f 1) and mould spores in apartment bedrooms before and after installation of insulated windows and central heating systems.

Attempts to determine the influence of the installation of highly insulated windows and central heating systems on indoor climate, and mite-allergen (Der f 1) and mould spore concentrations. A before and after study was carried out on 98 apartment bedrooms, with measurements taken of air exchange rate, temperature and humidity. A lifestyle and housing conditions questionnaire was undertaken by the occupants and dust on carpets and mattresses was analysed for mould spores and Der f 1. Increases were noted in temperature and absolute humidity, Der f 1 concentrations and the thermotolerant species of fungus. The air exchange rate decreased and relative humidity remained the same.