The housing estate in Gelterkinden, near Basel, Switzerland, consists of 17 residential units and combines ecological design with a high standard of comfort. The estate requires only half as much energy as conventional buildings, and this is provided by wood from the locality. Other factors incorporated in this project include improved insulation, chip wood burners, mechanical ventilation and rainwater collection. Four are semi-detached and three are blocks, each containing three flats, making a total of 17 homes. The seven buildings are grouped around an uncovered patio largely secluded from external view.
All buildings have four stories, including basement and attic.
The two upper concrete floors are carried entirely by the timber frame, and the internal walls are of masonry. The design finally chosen represents a compromise between embodied energy used in material manufacture and necessary storage capacity to ensure passive solar energy use and a high standard of comfort. The south-facing windows have a 'neutral' energy balance, i.e. window heat losses over the entire heating period are of the same order as utilised solar gains. Energy coverage by passive solar and internal gains, and auxiliary heating needs are shown in Figure 1. Energy balance and energy index.