Lots of people have argues that energy efficiency and other "green" improvements should improve the value of a house, at least commensurate with the investment, but survey data on the ground has been hard to come by.
Now a new study, “The Value of Green Labels in the California Housing Market”, shows that a green certified home adds 9% to its appraised sales value in California. Conducted by Nils Kok and Mathew Kahn of the University of California, the study is the first rigorous, large-scale economic analysis of the value of green home labels in California. Halleluijah!