The Unintended Consequence of Building Sustainably in Australia

What makes a sustainable house? One might suggest it should be energy-efficient, resilient to climate change and still comfortable. Indeed in Australia, we see aspects of these three priorities being exercised: energy-efficiency standards being introduced into residential requirements of the National Construction Code in 2003, bushfire requirements expressed as a national standard in 2009, and the constant demand for more efficient and round-the-clock climate control. All these actions relate to Sustainable Development Goal (SDG) 13: Climate Action. One might assume that these trends mark progress for both the environment and the home owners. However there is a dark side to the story, because in the very effort of reducing greenhouse gas emissions (also one of the functional objective of the national construction code), the construction industry has inadvertently implemented practices that have led to entrapment of moisture in buildings, thus compromising their habitability. Using data from Tasmania, this chapter shows how common mistakes in building science, design and construction have led to a widespread increase of condensation in buildings located in cool climates. Condensation has further led to other problems with mould and health (SDG 3: Good Health and Well-being), making new code-compliant houses potentially uninhabitable after experiencing their first winter. These challenges need to be in the wider discussion of architecture, construction, indoor microbiology and public health when sustainable housing standards are being promoted.