The environmentally responsible home morphed over the last 80 years, from passive solar to alternatives to ‘passivhaus’ to inner-urban apartments. The changing focus, and names, is the story of sustainability itself.

Australian architects, responding to the horrors of WW2, sought to design a better society, by adopting the ideals of modernism for suburban housing, relating design to the landscape and climate as expressed in Walter Bunning’s Homes in the Sun (1945), where climate response created courtyard designs oriented for both sunlight and privacy.

In the 1950s the Experimental Building Station continued these ideas with instructional booklets: Designing Houses for Australian Climates (J.W. Drysdale, 1952) and Sunlight and Shade in Australasia (R.O. Phillips, 1954). By ‘moral encouragement’ they hoped for better design, assuming that people would adopt passive solar homes if they had access to good, scientific ideas, but the impact on home design was limited. Mass production of standardised detached houses for the rapidly expanding population had little regard for energy costs or environmental impact.

Increased environmental awareness in the 1960s drove designs using alternative technology. A revival of vernacular forms, exploratory domes and autonomous houses were intended to address issues of ecology and energy. Mainstream housing was untroubled by a few remote hippy houses on the fringe, no matter how audacious.

The 1973 oil shock focused minds on broadscale energy efficiency. Research concentrated on water heating and thermal comfort, advocating bulk insulation, double glazing and internal thermal mass in floors and walls, drawn from European or US solutions targeting heating, ignoring the need for cooling the hot Australian climates. Books on highly efficient individual passive solar homes proliferated; ignored by business as usual.

In the 1980s efficient design became ecologically sustainable development (ESD), despite few designers having any working knowledge of ‘ecology’. The water cycle issues of collection, storage, use and recycling became prominent. A building’s long-term impact was now measured in life cycle assessment (LCA), adding materials’ embedded energy content and environmental concerns to operational energy.

By the 1990s the first wave of ‘moral encouragement’ showed little impact, so Governments started a second wave of regulation, legislating for responsible design. Codes started slowly, introducing minimum thermal performance standards through NatHERS in 1993. This highlighted the need to ignore overseas solutions, and address local radiant and convective conditions that require both coolth and warmth: external insulation or ‘outsulation’, shading and ceiling thermal mass for passive diurnal cooling.

In 2003 specific energy efficiency standards were regulated in the Building Code of Australia and in 2004 BASIX focused on energy, water and thermal comfort issues, better for detached houses than apartments at first, but gradually improved. Rainwater tanks, stormwater issues and on-site detention (OSD), were all addressed, but coal and wood fires were not banned. Gradually the everyday project house improved.

Digital modelling improved increasingly through the 2000s, with calculations promoting internal environmental quality (IEQ), measuring the effectiveness of the building’s envelope for interior spatial performance: thermal efficiency, natural and artificial lighting, natural and mechanical ventilation; all key issues in energy efficiency.

If regulation eliminates worst practice, the German idea of passivhaus promotes best. A home is super-sealed, with highly controlled fresh air, so that very little heating or cooling is needed. Extreme energy efficiency for thermal comfort. Its origins in subzero Europe have made its application in Australia controversial, many arguing the original passive design for coolth and warmth is more applicable in Australian temperate climates, with occupants used to opening and closing windows.

Since the early 2000s, widely available, affordable and super-efficient and photovoltaic panels (PVs) allow homes or apartments to generate electricity to offset usage. The panels can be on-site or remote, and their contribution can make the home carbon neutral, sometimes called net zero, or make more energy than used and be carbon positive.

Until 2000, the environmental performance of a home was determined solely on the building itself, but an increasingly holistic understanding of sustainability broadened concerns to the embodied and operational impacts of transport and infrastructure, so the planning issues of dwelling density and location became important in determining the carbon footprint.

By this measure townhouses and apartments, particularly well-positioned inner-urban ones, were more sustainable than detached houses or duplexes. By 2010 the search was on for the ‘Goldilocks’ density. Too low, and a suburban or remote high-performing passive or autonomous solar home will be overwhelmed by increased transport and infrastructure energy costs. Too high, and the energy demand for basement ventilation, lifts and especially air conditioning, cannot be offset by the reduced solar gain, despite its better location.

In the end there is no such thing as a fully sustainable home; the best solution we have now is a passive-based, well-designed ‘low and close’ cluster of dwellings, close to services.

Title image: An experimental solar / sustainable house designed and built in 1976-77 by the CSIRO at the Division of Mechanical Engineering in Highett, Victoria. The house gathered heat from the air based solar collectors, which was then stored in rock beds under house. Image by TW.

Next week: Designing for sustainability in the most sustainable form.

This is Tone on Tuesday #211, 4 June 2024, Much of this article was first published in the NSW Architecture Bulletin, Housing for All, Vol 80, No 2, 2023-4. It was written by Tone Wheeler, architect / Adjunct Prof UNSW / President AAA. The views expressed are his. Past Tone on Tuesday columns can be found here. You can contact TW at toneontuesday@gmail.com

Tone Wheeler

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