Growing environmental consciousness motivated a Dutch municipality to encourage energy saving and the use of solar energy for all new construction. This decision had an enormous impact. More than 4000 solar homes have been constructed. Those houses perform well. There is improved thermal comfort and in many cases improved indoor air quality. Energy use of the most recent constructions is a factor 4 down compared to energy use at the time of the first decision. These results were obtained without adding to the cost of construction.