Willowild, Johannesburg

This new Net Zero Carbon house was designed for the specific climatic conditions of the chilly Joburg winter night. The premise was that residential housing is used mainly during the evening so that should be the climate the architecture should be designed for. This house achieves Net Zero Carbon by using a heat pump water battery that runs off a 13 panel, 5 kW PV system with 10kWh of battery backup. Cooking is on gas with all external lighting as solar lights. All glazing is double-glazing with timber floors adding good insulation from the ground floor slab. The first floor is a timber floor made from structural Saligna with walls made from lightweight concrete polystyrene blocks. The building is therefore very well insulated with low thermal mass. A celebration of the timber is seen in the original sculpture hanging in the entrance hall also designed by the architects. Bathrooms keep the same white and wood theme using low flow fittings. The client proved that no additional heating is needed in the worst of winter conditions. We therefore see this as a successful alternative housing example for the Johannesburg context that directly challenges traditional brick, mortar and concrete construction.