Retrofit strategies influencing thermal performance in weatherboard-clad dwellings constructed before 2003 in a cool temperate climate

This paper explores simulation-based envelope performance improvements for typical low quality dwellings in southern Australia. Australia has over 7.6 million detached private dwellings 2005- 2006 data reported there were 6.3 million detached dwellings by 2005. Most of these were built prior to the 2003 national energy efficiency regulations. Pre-2003 dwellings are a significant concern as a high proportion of them have poor-quality building envelopes which are likely energy inefficient, costly to heat or cool and unhealthy to live in. Retrofitting them to provide better indoor environments is crucial for long-term sustainability goal. This paper describes a stage of PhD research that is investigating energy, thermal comfort, and health related indoor environmental qualities. Using the energy modelling tool AccuRate, this paper assesses external envelope improvement actions that can improve both energy efficiency and indoor environmental quality. Over 800 simulations were conducted exploring options to achieve a 6 Star NatHERS result. This paper finds that many pre-2003 houses likely have a house energy star rating below 1.5 Stars and that feasible retrofits can improve energy efficiency up to 6 stars. This paper contributes to further understanding envelope retrofit strategies and provides recommendations towards improved energy efficiency outcomes for existing dwellings.