Ventilation performance and end-user interaction: comparison of natural and mechanical strategies in new-build social housing

Adequate ventilation is critical to ensure effective removal of moisture, air pollutants and smells indoors. A growing body of evidence however suggests poor performance of ventilation strategies in modern housing, which raises concerns regarding the potential detrimental impact on indoor air quality. The risk of health effects resulting from exposure to indoor air pollutants is exacerbated by the reduction of natural infiltration rates brought about by improvements to the fabric performance of buildings. Whilst these improvements should help to reduce energy consumption and occupant discomfort due to draughts, there is a need to ensure ventilation does not deteriorate as a result. To ensure effective ventilation provision in modern social housing, it is important to understand and evaluate how these different strategies perform in a real-life context. This paper presents the results of a post-occupancy evaluation of three new-build social housing developments in Glasgow, ventilated by natural, mechanical extract and mechanical heat recovery methods. The study included household surveys of the three developments (responses from 63 households) and detailed monitoring of eight dwellings, to include occupant interviews, indoor environmental monitoring (during various seasons), fabric performance testing (airtightness, u-value assessment and thermography survey), energy monitoring, ventilation testing and indoor air quality measurements. The results provide interesting insights regarding how occupants engage and interact with the ventilation strategies, the performance of ventilation strategies in practice, and occupant awareness and understanding of ventilation. The findings indicate shortcomings in all evaluated ventilation methods.