In 2012, RICS developed a methodology to calculate the embodied carbon of construction materials issued as an information paper. A guidance note is due for release later this year, with a Code of Practice and practice statement also likely to be published. This RICS guidance will then become mandatory. In Construction Journal April/May, we considered embodied carbon and carbon accounting. Here we investigate how the existing guidance could be expanded on to assess the true carbon cost of new sustainable technologies. It is considered that between 85% and 97% of the buildings in existence within the UK in 2006 will remain in use in 2050. To meet the government’s demanding carbon reduction targets set for that year, the majority of these buildings will need to consider sustainable refurbishment of some form or other. In an ideal situation, all buildings would take a ‘fabric-first’ approach and apply passive design rather than relying on technical solutions. In reality, a large number of buildings will require an ‘embodied carbon intensive’ technical solution. How significant is this stage, and can the new RICS guidance be expanded on to include all sustainable technologies