Two key benefits of building retention and adaptation, over demolition and new build are identified in the academic literature: these are, the conservation of heritage, and reductions in embodied greenhouse gas emissions from construction materials. However, there is limited evidence on how these benefits are considered in decisions to demolish or adapt buildings in practice. A four year research project, including expert interviews, focus groups and three detailed case studies from the UK, Netherlands, and Australia, developed extensive data on how decisions were arrived at to demolish or retain individual buildings within larger urban development sites. The research found that heritage and embodied impacts are considered quite differently. Heritage is frequently a key driver towards retaining individual buildings. However, considerations of embodied emissions are seldom considered in the decision. Where there are insufficient arguments based on heritage value, many buildings are therefore demolished and replaced rather than retained. However, research has shown that in many cases, if embodied impacts are considered as well as operational impacts, this will lead to far higher whole life greenhouse gas emissions. To reduce the impact of construction on the environment it is therefore crucial that we calculate the embodied as well as operational impacts of demolition decisions and retain and refurbish buildings where this is the lower carbon choice. This paper proposes that understanding why ‘heritage’ is now accepted as a reason for retaining buildings might offer some lessons about the way forward for embodied carbon. Using heritage arguments as a basis, the paper then proposes that the introduction of a policy driver for retention and against demolition, and the conversion of environmental value into economic uplift, are likely to be necessary conditions to encourage the retention of buildings for lower whole life carbon.