The need to improve building performance to meet the challenges of climate change has led to increasing numbers of low energy houses being constructed and occupied. Given the drivers for rapid change and use of new materials and technologies, it is vitally important that we understand how these buildings are working to ensure that they meet expectations, both in terms of energy use but also liveability, comfort and health from the occupants' perspective. However, unlike other disciplines, construction rarely evaluates the performance of completed buildings. It is crucial that industry adopts these processes. These buildings are in effect a series of experiments, and the occupants are the subjects of these. There is therefore both a practical and ethical need to review the results and to apply this knowledge in future design.
This paper presents findings emerging from a two-year Building Performance Evaluation (BPE) study, funded by Innovate UK, of 26 new build low energy houses in Scotland, UK. The programme aimed to develop capacity for undertaking BPE and this research undertook detailed monitoring of energy consumption and internal environmental conditions, as well has gathering information from users about how they use their houses. Although it is clear that housing standards are improving, the study has found evidence of performance gaps between design expectations and actual performance, both in terms of energy and also the quality of the internal environment. This paper will present data from four case study houses, which illustrates both the effects of occupancy on performance, but also how the building performance can affect the occupants’ experience.