Measuring the carbon footprint of existing office space

Methods for assessing the environmental performance of new and existing office space cover a range of criteria that includes energy, water, materials and waste, health and wellbeing, pollution, transport, land use and ecology, but the overwhelming environmental objective is to reduce the amount of carbon dioxide (CO 2 ) emitted from office use. The two main sources of office‐related CO 2 emissions are building operation and commuting and, in these respects, existing buildings pose a different set of challenges to new developments; energy is embodied in the existing structure and systems, and the location is fixed in relation to facilities such as public transport nodes and amenities. Using standardised published metrics on CO 2 emission from office occupation and commuting, this paper estimates the amount of CO 2 emitted by the stock of medium to large office buildings in a large regional city in the UK. The results are put into context of government targets and current environmental performance assessment methods. The paper argues that the existing office stock of a typical UK city performs poorly in terms of CO 2 emission and that most current assessment instruments do not reveal the full extent of that poor performance. Depending on the instrument, this is for one or more of three main reasons: actual energy consumed/CO 2 emitted is not measured, insufficient weight is placed on CO 2 emission relative to other, often more qualitative green credentials, and either insufficient or no regard is paid to CO 2 emitted as a result of commuting and business travel.