Tell others to see http://www.thesolarvillage.com/ . Andreas Delleske is a member of a private group that built a "passive house" that uses only 1.5 litres of oil per square meter per year for heating. An architect and a biologist worked together to combine alternative energy and alternative waste management concepts. They found friends who were also interested and involved in energy topics. In the end sixteen members decided to build the home together in 1997. The house is composed of twenty units. The price overall of the building was only 7% higher than conventional new built homes. The house has a higher value since the residents pay very little for energy to heat the home. The entire structure required, which includes twenty units, each unit having about 90 square metres, and the annual utility bill was only 140 euros. Often people pay ten times this amount annually. By building with a group there are also savings in terms of sales and marketing costs. (less info)