Considerable guidance is available to the building industry for increasing the sustainability of individual refurbishment and redevelopment projects. However, there is very little information to allow a direct comparison of refurbishment and redevelopment options. Part 1 of this paper summarises the findings of a recent DTI funded research project to investigate sustainability of the two options. A simple online tool, Office Scorer, developed within the project, which allows users to compare refurbishment and redevelopment scenarios for a particular site. In Part 2 of this paper, case studies from using Office Scorer are presented. Quantitative results are given in ecopoints and costs per sq m or per person. Qualitative factors have been included in guidance pages of Office Scorer to guide the user to other sources of information on more specific issues. 12 pages.