House and Studio in Essen
A compact form and the integration of the house into the topography of the site were the keynotes of the ecological design. An optimum ratio of surface area to volume (in this case 0.73) helps to achieve a good energy balance. By building the house into the slope of the site on the north side, the ground can be used as a natural form of thermal insulation. The 6-metre-high concrete retaining wall, which also encloses the terrace at first floor level, acts as a thermal storage mass. Internally, further thermal storage mass is provided by the solid sanitary and services core. The prefabricated steel skeleton structure, consisting of columns and trussed girders, was erected around this core, with composite slabs in the form of reinforced concrete and ribbed metal sheets laid between the girders. The open areas between the steel skeleton frame are filled with timber stud wall units, with an aluminium post-and-rail façade on the outside. Broad areas of glazing ensure that the interior receives adequate daylight and fresh air from all sides. The sense of transparency is enhanced by internal sliding walls. Thermally insulating laminated safety glass prevents overheating in summer and allows a passive exploitation of solar energy in winter. In addition, a 6 m2 area of solar collectors on the roof supplies hot water. This low-energy house also contains a gas-fired condensate boiler and a low-temperature underfloor heating installation. A stove is provided for use on very cold days.