Mixed-method evaluation of the post-occupancy performance of 7 social houses in the Greater London Area compliant with the 2007 Code of Sustainable Homes (levels 3-5) conducted by Kingston University. The study asserts that whilst all dwellings are highly insulated, airtight and incorporate a wide range of innovative technologies (including PV systems, grey water recycling, mini Combined Heat & Power (CHP), high efficiency boilers with flue savers, MVHR and intelligent controls), occupancy behaviour is the most significant determinant of the indoor comfort conditions and the subsequent use of energy and water. For instance, there was significant variation in gas and electricity consumption when comparing similar dwellings and this demonstrates the enormous impact of occupancy behaviour.