<b>Energy efficiency in older houses: a parametric optimisation study on retrofitting a 1930s house in Adelaide, Australia00</b>

Improving the energy efficiency of housing is crucial to address the pressing challenges of climate change. Older houses in Australia built before the introduction of national energy efficiency regulations are often regarded as less efficient than recently constructed houses in terms of their energy performance. This study investigated the thermal comfort and energy consumption of a pre-war house built in the 1930s in Adelaide, Australia, through a combination of environmental monitoring, occupant responses, and building performance simulations. Results from the existing building’s thermal performance challenge the common assumption that older Australian houses are inherently inefficient. Parametric optimisation analyses of multiple retrofit strategies were conducted and compared against the Australian Nationwide House Energy Rating Scheme (NatHERS). The optimisation outcomes indicate that a strategic combination of insulation, reduced infiltration, upgraded glazing, and optimised external shading can lower total heating and cooling loads by up to 78% compared to the original design.