Think Brick Sustainability Blog

Recently Think Brick Australia conducted a small study to compare how the 2nd generation thermal modelling software programs AccuRate (developed by the CSIRO) and BERSPro (developed by Solar Logic Pty Ltd) rated various walling constructions in Australia’s capital cities.

The purpose of the research was to better understand how different walling constructions were rated and to provide information for our sales representatives as they started conversations with builders and architects about the Government’s new six star legislation.

In doing the work we noticed considerable differences in how different software rated the same house in the same location. After seeing the National Energy Efficiency Strategy draft and some of the policy proposals such as mandatory disclosure, we published the thermal modelling comparison and suggested that such large variations would be problematic under a policy of mandatory disclosure.

After discussions with ABSA – the industry body that accredits both software and assessors of building sustainability – we have been made aware of how variations can occur (assessors make different assumptions, use slightly different walling constructions, orientations etc). Although we used two different assessors (one per software) we did make every attempt to minimise other variations by detailing the relevant assumptions, postcodes, orientations etc and therefore believe the rating variations should have been minimal.

Nevertheless, in fairness to ABSA (and to avoid our information being used as an example of why energy efficiency policies should not proceed), we have removed the comparison from this site while ABSA undertakes a rigorous assessment of not only the houses in question, but also other factors that can produce variations.

Although ABSA have not provided a timeline for this research, we applaud their commitment to understanding the limitations of, and ultimately working to improve, thermal modelling software.  Building design is a complex system with the integration of multiple facets which can only be understood completely through the assistance of simulation tools.

Think Brick Australia hopes that through this work, and with the assistance of other tools such as Designing for Climate, the Australian building industry can start to develop not only minimum compliance six star houses, but also superior 7-,8-,9-, and 10-star houses that ultimately use no energy!