New research from UNSW Sydney has found that external shading is the most effective passive upgrade for keeping older high-rise social housing cool. It cut the number of hours above30°C by up to 50% under future climate conditions.
Led by Dr Gloria Pignatta and published in City and Environment Interactions, the study modelled retrofit options for two Sydney social housing towers without air conditioning: Northcote Towers in Surry Hills and Morehead Towers in Redfern. The researchers tested external shading, insulation, double glazing, improved natural ventilation and reflective façade coatings.
Without upgrades, hot hours in these buildings could climb from around 100 a year now to almost 175 by 2050. Some west-facing apartments could see an increase of up to 74%.
The full paper notes that while overhang shading is highly effective at reducing summer overheating, it is rarely used in practice. The researchers point to structural integration challenges, limited regulatory familiarity, and concerns about compliance with high-rise safety requirements under the National Construction Code (NCC). They also note that funding processes tend to favour conventional solutions.
Governments are investing heavily in social housing upgrades. The federal Social Housing Energy Performance Initiative was first funded in the 2023–24 Budget and has since been expanded with almost $500 million in extra funding. The expansion runs in every state and territory until June 2031, and window shading is among the upgrades covered.
This research adds independent evidence to WSAA’s push for shading to be properly recognised in the NCC and in government energy-efficiency programs. When the evidence shows shading delivers the biggest gains, the rules and funding should make it easier to use, not harder.
