Abstract Energy Performance Certificates need a degree of consistency if the information provided by these documents are to be used for applications designed to improve the energy efficiency of the building stock of a country. This study demonstrates, through investigations of small samples of dwellings, that the level of quality, and outputs, from a standardised energy assessment can be variable. Multiple assessors evaluating the same property can produce quite markedly different results and, therefore, recommendations for what that household should do to reduce their energy consumption. Using the results of studies conducted by the authors and from elsewhere, qualified commentary is provided relating to what this form of energy assessment should be used for, and whether improvements can be made in the future as areas of policy look to reflect the recorded energy performance of dwellings through a range of policy vehicles.