In the UK it is well documented that the domestic buildings we occupy contribute significantly to anthropogenic climate change, through their energy consumption and associated carbon dioxide emissions. To reduce these emissions, strict legislative targets require considerable changes to the construction of dwellings (for instance, by improving insulation and air tightness) and also to the technological systems that service them (both passively and actively). Routine validation of, and feedback from, the operation of occupied buildings is seldom conducted despite growing evidence that performance often aligns poorly with expectations or even traditional equivalents. Furthermore, the extent to which the performance of buildings is assignable to the structural and technical features, rather than the actions of the occupant, is not well understood and can lead to profligate consumption and improper (or unexpected) utilisation of design features. The contributions to knowledge documented in this thesis are two-fold. The first contribution is a survey tool and interview structure to capture information on domestic occupant behaviours, which can explain a proportion of performance variation between otherwise comparable dwellings. Five case studies are reported on, alongside wider performance assessments (including occupant comfort and satisfaction, resource consumption and associated carbon emissions, and building integrity). This constitutes the second contribution to knowledge: performance results from four nominally low-energy and low-carbon domestic sites. The fifth case study site was selected to represent a traditional, non-environmentally informed development. Both contributions resulted in individual peer-reviewed academic journal publications. In the absence of measurement, building performance can only be assumed and hence compliance with design expectations or progression towards strict legislative targets cannot be validated. At the low-energy case study sites, average total normalised carbon emissions ranged between 22 and 34 kgC02/m2/year, 39. - 65% lower than local and national benchmarks and most sites exceeded overall comfort and satisfaction benchmarks. At each site large household-to-household variations in consumption of resources and carbon emissions confirmed the importance of human factors (factors of difference ranged from 2.7 - 36). Occupant behaviour, in some houses, undermined overall performance and compliance with standards and design expectations. Interviews with residents at two sites enabled unprecedented access and insight into behaviours and helped explain performance variation in depth. The survey, which aimed to provide a repeatable and rigorous method for capturing behavioural data, explained between 7 - 48% of overall performance variation and facilitated detailed investigation of pertinent behaviours. Socio-demographic and• lifestyle factors are proposed to explain the varying accuracy and inconsistency between individual site results and are of interest for further work and method refinement.

There has recently been considerable concern regarding the degradation of the environment caused by depletion of natural resources, air pollution, global warming and the lack of consideration paid to the earth's ecosystem. The principles of sustainable construction are thus being widely adopted by many countries all over the world. This quest towards sustainable development throughout the world has put a spotlight on the construction industry. Sustainable construction is a major concept underlying a variety of efforts to ensure a good quality of life for the present and future generations. Most developing countries have experienced a fast uptake of urbanisation and the acceleration of infrastructure development, all of which fuel the necessity of establishing sustainable construction principles; this is true in Saudi Arabia as in other countries. This research has carefully investigated the current situation of Value Management (VM) and Sustainable Construction (SC) in the Saudi construction industry in terms of their application, clients' attitudes, barriers to implementation, identification of enablers that could overcome these barriers and improve their implementation, and determination of the level of existent knowledge about both subjects among people who work in the Saudi public sector. It has also defined Sustainable Construction principles in three dimensions, in Saudi Arabia: environmental, economic and social. The research findings have revealed that SC principles are not a major consideration in the Saudi construction industry and many people who work in the Saudi public sector have little or no experience in sustainable development. On the contrary, VM has been applied in the Saudi construction industry for more than three decades and its application is mandatory in all governmental projects funded by the Saudi government. This enables those people who work in the VM sector to possess great experience, skills and knowledge. However, there are a number of barriers that could impede or affect the VM performance in the Saudi construction industry which were taken into account in this research. (Continues...).