STEP 01: UNDERSTAND THE CLIMATE

Until you understand the climate you are designing for, you can’t design a more sustainable home. That’s why sustainable home design is sometimes also referred to as climate responsive design.

In Australia, we have a wide range of different climatic conditions, as can be seen on this climate map published by the Australian Building Codes Board:

The eight general climate zones found in Australia.

Using climate and weather data compiled by the Bureau of Meteorology, eight distinct climate zones have been identified. Most Australian capital cities are located in climate zone 5, which is considered a temperate climate, meaning both heating in winter and cooling in summer is required to help maintain thermally comfortable conditions. General climate characteristics can be summarised as follows:

  • Winter: days are cool to cold; nights are cold
  • Summer: warm to hot conditions both day and night
  • Moderate to high humidity

Sometimes the way we perceive climate and weather conditions is not necessarily what the data shows. For example, in Perth, there are actually more days throughout the year when it is too cold as opposed to too hot. When you examine the climate data, while there are 1-2 months of really hot days from December to February, there are actually more days when it is just a bit too cold for comfort from around May through to September. This is the case most towns and cities located in Climate Zone 5.

Once we have an understanding of the climatic conditions we are dealing with, we can then start to formulate an appropriate design strategy in response. One tool I find particularly useful is a bioclimatic chart. It was first conceived by Hungarian architect Victor Olgay around the mid 1950s. Using a bioclimatic chart, we plot monthly average temperatures and humidity, which ends up looking something a bit like this:

CHART 1

A bioclimatic chart for Perth. Western Australia.

The bioclimatic chart provides us with an overview of the climatic conditions, and which low-energy or sustainable design strategies are likely to be the most effective. Using the above example, I would look to apply the following design strategies:

  • There are more times of the year when it is too cold than when it is too hot, however it can get very hot!
  • In winter, we can use full passive solar heating to help make the building comfortable
  • In summer, a combination of thermal mass and natural ventilation can help to keep occupants cooler

In summary, there are also times of the year when the prevailing conditions should be thermally comfortable – if the building is designed appropriately we should be able to substantially reduce the need for artificial heating and cooling to make it comfortable.

Further Reading:

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