The 1st piece of work I did for the Sustainable Housing Action Partnership with urbed to develop a set of retrofit archetypes that would reduce bills and emissions by 80%. The social landlords of SHAP  provided us with real properties and for which I built a bespoke version of SAP2005 to be able to model the most effective suite of energy efficiency measures. These were then costed. The base specification has proved accurate and highly effective since.