Low-energy dwellings: the contribution of behaviours to actual performance

The UK Government's Building a Greener Future: Policy Statement (2007) announced that all new homes must be zero carbon from 2016. To date, a number of housing sites around the UK have strived to reduce carbon emissions by following sustainable design principles and utilizing renewable technologies. On paper, these sites exceed regulatory compliance and are regarded as high-performance buildings. However, their actual performance is seldom validated from the perspective of either the design engineer or the occupants. Findings are presented from an on-going post-occupancy evaluation of a UK EcoHomes site with an 'excellent' rating (the highest rating of the predecessor to the current standard, the Code for Sustainable Homes). The detailed post-occupancy evaluation investigated the energy performance of the buildings (as well as water consumption) and the comfort and satisfaction of users. A bespoke behavioural survey and interview were developed and implemented to distinguish between and quantify frugal and profligate patterns of consumption. Results indicate that energy-efficiency behaviours account for 51%, 37%, and 11% of the variance in heat, electricity, and water consumption, respectively, between dwellings. Human factor issues need to be addressed more adequately as standard practice in low-energy/carbon design.