This report is a product of the collaborative research project ‘Validating and Improving the BASIX Assessment Tool for Low-Carbon Dwellings’. Initiated by the Cooperative Research Centre for Low Carbon Living, the University of New South Wales (UNSW) and the New South Wales Government, this project addresses the policy need for post-occupancy evaluation of the BASIX tool by measuring the actual energy consumption of BASIX-compliant dwellings. This report outlines the key findings of this project by highlighting the discrepancies between BASIX estimations and measured energy consumption and provides an in-depth analysis as to why there are discrepancies and what causes them. Project outcomes fill the gap towards achieving a systematic understanding of actual energy performance of BASIXcomplaint dwellings, including the complex and interrelated attributes that contribute to these discrepancies.
Findings from this research show that the measured BASIX-compliant dwellings performed well in the overall reduction of greenhouse gas emissions and were close to BASIX estimations, thereby validating the effectiveness of BASIX tool in promoting low carbon dwellings. However, the breakdown of energy consumption measured by this project highlighted discrepancies in energy consumption for space heating and cooling, lighting and plug loads. An analysis of the attributes contributing to these discrepancies between BASIX estimates and actual energy consumption is discussed and recommendations for future improvements are presented in line with:
Updating and improving the benchmarks utilised by the NatHERS and BASIX assessment models;
Improving construction and building envelope quality control; and
Encouraging sustainability awareness and behaviours.
A rapid review on green-rated office buildings, and their operational energy use, found that the conclusions of six studies ranged from the certified buildings performing worse, similarly or much better than the non-certified buildings in terms of energy usage intensity. Two...Read more
Industry misconceptions around high cost and poor market interest in energy efficient homes continue to obstruct the mass adoption of low carbon housing. Josh’s House demonstrates that low carbon housing is accessible and cost effective. The Star Performers series showcases how...Read more
In response to feedback, high-income households can reduce their energy use to a larger degree than low-income households (17% vs 3% reduction). This and other insights were gained by two rapid reviews into research, both Australian and International, on digital services and...Read more
The Building Sustainability Index (BASIX) assessment tool estimates the operational energy consumption and GHG emissions from new residential developments based on information available at the building design stage. However, post-occupancy energy consumption can be different from the estimated figures at the design stage.
Buildings are major consumers of energy for heating and cooling. The number of buildings is growing rapidly with demand for energy. To reduce consumption, governments worldwide have implemented codes, standards, and building practices.
Sustainability assessment tools aim to promote high sustainability outcomes in residential buildings, ensuring less consumption of water, energy and less emission of greenhouse gases. However, existing literature often presents variations between the estimated outcomes from the assessment tools and actual outcomes after building occupation.