Developing building typologies to examine energy efficiency in representative low cost buildings in Cape Town townships

Studies for building designs exist both internationally and, to a lesser degree, in the South African context. However, there is limited understanding of the various types of low-cost buildings and their related energy flow patterns, as found within townships and other informal urban settlements within the City of Cape Town. This study thus developed a typology of representative low-cost building types based on their energy profile in two townships in Cape Town: Gugulethu, and Manenberg. The buildings were classified into eight representative types: Rowhouses; Maisonettes; Cottages; Courts; Government Reconstruction and Development Programme houses; Migrant labour hostels (1-storey); Migrant labour hostels (2-storey); and buildings known colloquially as '2-storeys'. DesignBuilder and EnergyPlus energy profile simulation results demonstrate that high energy consumption of low cost buildings is due to: poor building orientation; high occupancy rates; non-insulated walls and roofs; lack of ceilings; the use of kettles as a primary source of water heating; and inefficient incandescent lighting. Based on the household appliances and lighting, the results show that Maisonettes have the highest average annual energy consumption per square meter relative to the other building typologies, at 515 kWh/m2/year. However, Migrant labour hostels (1-storey) show the highest annual energy consumption at 16741 kWh/year, based on the household appliances and lighting. Opportunities to improve energy consumption efficiencies in low cost buildings in the two townships relate to both contextual analysis of the building types, and the household lifestyles related to energy use.