In Its Right Place

Climate and Structure in Australia

At the root of these different types of climate is the subtropical high pressure belt that moves north and south depending on the time of the year. The belt causes the rainfall pattern to vary greatly from season to season. Indeed, Australia has less rainfall than any of the other seven continents besides Antarctica, and a drought can last several seasons.

The size of the continent isn’t especially large, and it is separated from the polar regions by the southern ocean which is why the country doesn’t experience the same cold air that is felt by the northern hemisphere during the winter. The countries in the northern hemisphere have a significant contrast in temperature between summer and winter whereas in Australia, the temperature doesn’t vary in such a significant manner.

Seasonal highs and lows in Australia can, however, reach above 50 degrees Celsius and plummet to well below zero. Most low temperatures are caused and moderated by the lack of mountain ranges and the air that blows off the oceans; since Australia is essentially a large island, the surrounding oceans can greatly impact any coastal region.

Australia is the continent that is most vulnerable to the effects of El Niño; it experiences considerable droughts and very wet periods. Occasionally the continent is affected by dust storms which can blanket an entire region, as well as tornados. The El Niño Southern Oscillation is also the cause of tropical cyclones, heat waves, many brush fires and frosts. Salinity and desertification are also slowly affecting the continent as they ravage the landscape.

Australia is one of the driest continents on Earth, wherein the better part of 80 per cent is known to only receive about 600 millimetres of rain throughout the year. Lake Eyre, located in the Southern part of Australia, only receives about 81 mm of rain in a year while some parts of Northern Australia will receive more than 4000 millimetres. Australia’s record precipitation in one year was 12461 millimetres – that was dropped on the summit of Mount Bellenden Ker in the year 2000.

Cold ocean currents off of the west coast, low elevation of landforms, dominance of high pressure and the shape of the continent are all factors that greatly affect the amount of rainfall. In the Australian Desert, precipitation can be as low as 200 millimetres, with an average of 15 – 20 thunderstorms per year. Temperatures in the summer can reach 50 degrees Celsius and in the winter the temperature can fall to 18 degrees Celsius.

Southern Australia typically feels westerly winds and cold fronts that come with rain as the high pressure systems move northerly during the winter. Sometimes frost will appear inland while the temperature near the coast is most often mild. Coastal breezes are the reason that the summer in Southern Australia is so hot and dry; during a lengthy dry spell, the winds from the interior can even cause brush fires.

The tropical areas of Australia have a wet summer because of monsoon presence; this wet part of the season usually falls between October and April when humid North-Westerly winds bring thunderstorms and showers. This area is also prone to tropical cyclones that can reach further inland where water is needed.

Snow falls on the east coast, in the states of Victoria, ACT, New South Wales and Tasmania –these areas actually enjoy a fair bit of skiing tourism. Snowfall also occurs in the mountains of South Australia, Western Australia and Queensland but it is very rare.

The fact is, talk of the country’s climate could fill several volumes, and this is precisely why this subject is very important within the construction trade. When dealing with the construction of homes and other buildings, the weather plays a very important part in how the structure will be designed. Since the country that we live in has such a diverse climate, every home will have different characteristics.

Not just any design will do for any climate; when choosing a design there are a few key characteristics that must be looked at. The main characteristics of the Northern tip of Australia are the high humidity, high temperatures all year, minimal seasonal temperature variation and the smallest day and night temperature range. As a result, houses in this area are usually built of lightweight material that won’t hold heat energy; they make use of broad external wall areas to encourage cross ventilation or passive cooling, and most of the houses in this climate will have ceiling fans, reflective insulation and vapour barriers, ventilated roof spaces, and will often be elevated off the ground to allow a breeze to flow beneath the building.

These buildings often have a light coloured exterior, including the roof, high ceilings, and sleepout spaces, and even though they may be build out of lightweight, low mass material they must be strong enough to withstand a cyclone. The positioning of the building is also very important. Year-round shade will cut the heat, whether it encompasses the whole house or is provided by shaded outdoor areas for lounging on a beautiful day. Before all of the aforementioned characteristics can be designed, however, the home builder must decide whether or not the building will be mechanically cooled or not; if it is then the design has to include bulk insulation.

Most of the East coast will experience high humidity as well as a dry season. The summer season will be very hot, or just bearable with a distinct temperature change from summer to winter. The night on this coast won’t feel much different than the day time but this changes as one heads inland, so contractors must make use of different materials depending on how far the structure is from the ocean.

Lightweight material is used on the coast while the same material is used inland with a touch of thermal insulation to store the temperature at night. Cross ventilation is key here as well, so broad external walls are important, as well as placing the building in an area where it will catch a breeze. It is also recommended that these buildings be shaded in the summer, but access to the sun in the winter months can go a long way for heating.

With a good design within this area, auxiliary heating is often not needed if the home is built properly. Reflective bulk insulation and vapour barriers should be employed, especially when an air conditioner will be used. Elevated, enclosed floor space is useful in this region as well as light coloured external materials and plenty of shady outdoor spots.

Structures that are built on the central West coast and central inland – for example, Exmouth to Longreach – can expect low rainfall, low humidity, a warm winter and very hot summers as well as a very broad range of temperature from night to day. Houses in this area will need plenty of mass insulation, passive cooling which utilises cross breeze and effective site placement. Houses in this region can make use of convective ventilation, which vents hot air while drawing cooler air. Good use of shading can provide a cooler day, and it is recommended that these dwellings shade the east and west walls from the sun. Also recommended are garden ponds and other water features that can provide evaporative cooling.

Just below that region, from most of the Southern coast and inland North to about the centre of Australia, there are distinct seasons throughout the year. There is a high range of temperature difference from night to day, low rainfall, hot summers and cold winters. In these dwellings passive heating and cooling is very important, as well as bulk insulation. Convective ventilation is useful as well as a building shape that is compact and allows a good cross-breeze. These houses should be built with access to the sun, exposure to cooling breezes and cool air drainage. These structures should have some sort of protection from the strong winter wind gusts as well as the occasional hot summer sand storm. Shade should be available for any windows that are on the East or West walls.

Even though this area is hot, the use of air-conditioning should be avoided, while reflective insulation should be employed to keep out the summer heat and the winter cold. Bulk insulation should also be used in the ceilings and under the floors; windows could also be double-glazed. Evaporative cooling can be employed for the summer months as well as large shaded outdoor living areas.

The very South-Eastern point of the continent is considered a cool temperate area. This area has low humidity, with a high day and night temperature difference. This region has four very distinct seasons with cold winters and hot summers. The majority of the rainfall comes in the winter but the summers are hot and dry.

Homes in this area should be built with passive solar principles, high thermal mass throughout the entire home, including the slab edges. The broad side of the house should be facing north, and windows should be double glazed with well insulated frames; thick curtains could also be used to keep the cold out. These homes should have some sort of adjustable shading, and they should be placed in a spot where there will be solar access in the winter along with a cool breeze in the summer. Draught sealing and air locking entries are recommended, as well as auxiliary heating. Heating systems that make use of renewable energy are popular. Use reflective insulation to keep the summer heat out and bulk insulation throughout the home to keep the cold winter at bay.

Smart construction firms will build with an eye toward the climate, and the best designs often work with their location rather than against it. With appropriate design principles, the right materials and a little bit of ingenuity, homeowners all across Australia can be assured of comfort, beauty and functionality.

Home Automation

Call it ‘domotics,’ and you are likely to receive a blank stare, but refer to it as ‘smart home’ or ‘home automation,’ and you will get a nod of acknowledgement. For the past few years, consumers have heard the word ‘smart’ attached to countless products and services, from food and drink to snacks like popcorn and mobile phones, which no one seems to refer to as a ‘cellphone’ anymore. Yet what, exactly, constitutes ‘smart’?

January 17, 2019, 6:29 AM AEDT