This paper develops existing work on building design through a focus on one important yet understudied form of regulation: market standards. Market standards are agreed upon definitions of ‘necessary’ provision in buildings and are fundamental in ‘formatting’ markets and determining the value of a building in the market. The paper presents a case study of the design of ten commercial offices in London, UK, the effects of market standards on the designs and on the potential for the development of lower energy buildings. Theoretically, the paper integrates literatures on standards, institutions and markets to argue that market standards do important ‘work’ in design processes that requires closer scrutiny. In particular, we show that market standards: are an important form of normative and cultural regulation in the field of commercial office design; format and act as calculative devices in property markets; and result in forms of knowledge diminution that break the relationship between building design and occupiers’ practices. Together, these effects result in particular designs being legitimised and valued, and lower energy designs being delegitimised, devalued and pushed to the periphery of the attention of commercial office designers.