Involving occupants in net-zero-energy solar housing retrofits: An Australian sub-tropical case study

Abstract

Australia has a poor record of enforcement and compliance with national energy efficiency building regulations introduced in 2003 and moderately enhanced several times since. A significant challenge facing the nation and owners/occupiers of poor performing houses is how to retrofit the existing building stock to meet thermal comfort, lifestyle, energy efficiency and climate mitigation expectations and standards now and into the future.The purpose of this study was to test a strategy for providing a range of information to the home owner to assist in their renovation decisions to achieve a net zero energy home in sub-tropical Australia and to evaluate the impact of their decisions in terms of net energy balance. A decision-making equation, rather than an economic-rationalist cost equation, was used to evaluate household actions.The results show that a combination of a citizen science approach, simulation tools and experimental data assisted occupants in achieving a 50% improvement in building thermal efficiency, an annual average daily consumption of 20.1 kWh and solar generation of 19.6 kWh.The cost of these actions was well under the average retrofit budget in Australia and resulted in the house achieving near net zero energy (NZE) balance for all household services on an annual basis and NZE balance for nine months of the year. Analysis of the motivations and actions of the home owner point to implications for building assessment tools, eco-feedback technologies, policy, and theories of household decision making.