preface
Early European design influenced the use of shading and ventilation strategies. The wraparound balconies and typical queenslanders are examples of responses to the harsh Australian summer. This design response is often matched by children playing under a lawn sprinkler or sleeping on a balcony to catch the night wind.
The rise of air conditioning has taken us away from climate-sensitive and culturally sensitive ways of providing comfort in extreme situations. For many, the push of a button offers superior and controllable comfort. This has led to high costs for energy and energy infrastructure, especially at the height of heatwaves. It will also increase emissions of carbon dioxide, the main cause of climate change.
Design for climate
Low – and zero-energy homes can reduce energy demand and environmental impact. They can also improve habitability, affordability and the health of the occupants.
These homes represent a reinterpretation of modern climate design based on energy and materials science. The home is a combination of passive solar design, building material characteristics and technology to reduce energy use and provide energy on site. In this context, recent research conducted in south Australia raises the question: have we forgotten coping strategies to actively manage our thermal comfort? We interviewed residents of the green village of Lochiel park in Adelaide to explore their living history to understand the changing relationship between occupants, buildings and energy use. Rochelle park is the first major residential project in Australia to use nearly zero energy in a zero-carbon zone. The families were rated at least 7.5 nasers stars. They have double-glazed Windows, ceiling fans, solar water heaters, solar pv, energy-efficient appliances and energy feedback displays. All these features were and are well beyond the requirements of the building code.
Studies have shown that residents used different measures to adapt to extreme conditions in their previous homes. They discussed strategies for sleeping downstairs, in well-ventilated corridors, or under corridors outside, where temperatures drop faster at night. Typical behavioral responses include active management of the house, such as closing curtains and shutters to block out the sun, fixing temporary sunshades, or opening the house every night to let in the valley breeze. The introduction of air conditioning changed buildings and lifestyles. Single-room air conditioning has redefined strategy: instead of sleeping outside, residents can drag mattresses into their living rooms. The local swimming pool is no longer so attractive. As one resident put it: “… I’m not going to go swimming in this hot weather.” External shading or curtains are no longer considered necessary. Blinds and other lightweight window furniture became popular. Active action by opening and closing Windows, doors, and curtains becomes less important.
The almost forgotten strategy
A new generation of families is growing up in an environment where they don’t need to learn the previously essential positive coping strategies. The move to purpose-built, low-energy homes was designed to engage the occupants actively, reintroducing some of the almost forgotten coping strategies.
However, they are placed in the context of contemporary social perceptions of public safety. For example, one homeowner pointed out: you’ll sleep outside. Do this now and you may not wake up in the morning. For some, the houses promise “perfect comfort” and no need to cool down. The study found that moving to a “low-energy” home reduced, rather than eliminated, their active participation. Data from monitoring temperature and energy use showed that the losier park house performed significantly better than most other homes. However, the houses are only 7.5 stars out of 10, so their investment does not provide year-round “perfect comfort” for the occupants, who do not need to adapt or actively heat or cool.
Tracking residents’ housing history reveals a dynamic response to extremes and attempts to create a comfortable indoor environment. Comfort has shifted from being primarily the achievement of the householder to the result of technology and, more recently, becoming the property that the occupants expect their buildings to provide. Whether and when net-zero-energy homes will replace the current housing stock remains to be seen. It is clear that even in high-performance housing, residents still play a role in creating comfortable temperatures and coping with extreme climates. A key concern is that “forgetting” traditional comfort practices will increase our vulnerability and reduce our ability to adapt to heat waves. As we saw last week, more than 200,000 homes across Victoria are without electricity on a rolling basis, and in extreme weather conditions, relying on air conditioning poses a challenge to our energy grid. The impact on emissions creates a double problem with this dependence.
Is zero carbon a zero carbon house
Although this monitoring is only two years old, we are already seeing strong trends. Homes in Lochiel Park, for example, use significantly less energy than the south Australian average and only a third of the energy consumed by an equivalent new home. This is a significant savings for the lokiel park residents.
The energy performance during the peak of the summer heat wave is outstanding. Not only did electricity demand for the lowhill park home decrease significantly, but — thanks to excellent thermal comfort levels — demand peaked later in the day, helping to flatten the entire Adelaide load curve. Due to the production of renewable electricity from solar photovoltaic panels, many homes in rothschild park are performing at or near the expected performance of net zero carbon homes. Detailed monitoring will help us understand what elements of the guidelines could be improved to provide a low-cost, zero-carbon net standard for all new housing construction on average.
