Towards net zero energy for older apartment buildings in Brisbane

Abstract

Between 1961 and 1981 the number of Australian apartments more than tripled in response to booming post WW2 immigration, growing local manufacturing industries and the new construction skills of migrants. The Australian Bureau of Statistics records more than 500,000 brick multi-residential dwellings constructed in this period. This cohort is very consistent in construction method, with cavity brickwork external walls, rendered brick internal walls, concrete slab floors, and roofs typically made of an uninsulated low pitch metal sheet. These buildings were built in an age where there were no energy or water efficiency regulations and many remain close to original condition. They are now around 40 years old and are facing the need for replacement of substantial parts of their building envelopes. The uniformity of this building type and the number of dwellings involved make it worth investigating what renovation strategies could be implemented to improve their energy efficiency and indoor comfort conditions. International examples show that substantial energy demand reduction is possible, and net zero energy is an achievable and cost effective target for similar apartment buildings. This paper presents initial results of ongoing research into the current condition and future value of 1960s and 1970s apartment buildings in Brisbane. Modeling tools are employed to assess hygro-thermal behaviour and energy consumption of a typical building, comparing its current and post energy retrofit performance. The feasibility of the most effective retrofit strategies is then evaluated in light of socio economic factors, and conclusions are drawn about the best future for these buildings and their inhabitants.