Pilot study to investigate indoor air quality (IAQ) in energy efficient homes in Ireland: Report prepared for EPA STRIVE and Sustainable Energy Authority of Ireland

Abstract

Within this pilot study a number of Indoor air pollutants were measured in five energy efficient homes built to enhanced standards of air tightness of between 0.75 m3 /hr/m2 and 8.75 m3 /hr/m2 . The five homes were built according to the requirements of the 2007 Building Regulations. The objective was to evaluate whether increased standards of air tightness impacts on the indoor air quality and thermal comfort the home. The selected homes were a mixture of 3- and 4-bedroom semi-detached houses, and were occupied. Two of the houses had mechanical ventilation with heat recovery (MVHR) system, while the other three houses used natural ventilation. Indoor air quality measurements of selected pollutants, i.e. particulates (PM2.5, PM10) , nitrogen dioxide, formaldehyde, total volatile organic carbon, carbon monoxide and dust mite concentrations, and thermal comfort parameters, i.e. temperature and relative humidity, were carried out over sampling periods of 24 hours, 7 days and 14 days, respectively. In addition, air exchange rates of selected rooms within each individual home were established. Diary records of occupant activities and household questionnaires on the homes and their indoor environment were also collected. In general the levels of pollutants measured in this project were within recommended guideline limits. Variations in pollutant concentrations could in most cases, be correlated to certain activities within the individual homes, like for example cooking, smoking, or redecorating. However as this was a small scale project it is difficult to draw definitive conclusions regarding the impact of increased air tightness on indoor air quality and thermal comfort. A larger scale study, building on the findings of this pilot project, is recommended. There is a lack of data internationally on indoor air quality in highly energy efficient homes. A larger scale project should include a broader range of building types such as detached or terraced houses and apartments etc. and should also include a larger number of homes which use energy saving technologies such as MHVR. This study would also look at how indoor air concentrations vary by season, it is likely that higher concentrations maybe found in the winter period, during periods of maximum fuel use and maximum occupancy. A larger study would also include a qualitative element such as a National survey, of key stakeholders working in this area. The aim of the survey would be to collect information on the le vel of knowledge, the usability and suitability of the energy technologies available to home owners today. Experiences gained in this project, seemed to suggest that there is a lack of knowledge among some members of public on what energy efficient technologies are available and it was difficult to find 3 or 4 bed semi detached homes who were using energy saving technologies to participate in this pilot study.