Quantitative research has been lacking to support this contention. However, as reported in award winning US blog Jetson Green, recent research conducted by the Earth Advantage Institute, an Oregon-based non-profit organization, found that new homes with a green certification (US Green Building Council’s LEED in this instance), sold for 8 per cent more than new homes without a certification. Moreover, existing homes with a green certification sold for 30 per cent more than homes without such a certification. The research was carried out in several districts in Washington, Oregon, and was based on sales between 1 May, 2010 and 30 April, 2011. While there were differences from district to district, the overall results strongly supported the notion that both new and existing homes with a green certification have higher sale values.
The contribution made by thermal mass is not fully recognised