To provide a toolkit to meet current and future needs for optimisation of life cycle costs, energy costs and CO2 emissions. Drivers for these requirements reside in public procurement guidance such as HCA funding, the legally binding carbon budget (2009), the Low Carbon Industrial Strategy, anticipated outcomes form the Low Carbon Review of the Construction Industry, Achieving Excellence Guides as well as more broadly in the proposed changes to Building Regulations and the Latham report. BLP surveys and interviews with professionals confirm the need to assess alternative designs quickly and accurately to achieve sustainability targets such as Code for Sustainable Homes (which will be modelled in the application). The toolkit enables best value for money not only to be assessed in context of capital and operating costs but determination of best reduction in carbon for money over the life of the building.Significant energy improvements are required to the existing building stock to meet the 80% reduction in CO2 emissions target by 2050 (Climate Change Act 2008) and the European Unionj target of 20% reduction by 2020. The energy efficiency of existing building and retrofit measures will need to be addressed effectively over the life cycle.