Adelaide has a a climate with four seasons. Improving summer and / or winter thermal performance will make autumn and spring longer.Summer cooling costs are a fraction of winter warming costs. The best and most cost effective improvement is roof-top solar PV. It will save money every day and shade your roof in summer.
2. Solar hot water will provide around 240 days of free hot water and will support water heating in winter.
3. Reduce power use - LED lighting will pay for it self in six months and they last for ~ 10 years. And if you not using it, switch it off (lights, TV, modem, computer, printer)
4. Insulation - Upgrade roof insulation to R6. Control draughts to reduce heat loss/gain. Good for summer and winter.
5. Heavy window drapes floor to ceiling with closed pelmets reduces heat gain/loss due to warm air rising/falling behind curtains. (This is as effective as double glazing (but you can't see through it).
6. If you have east/west windows have a roller shutter put on the outside preferably white. This will dramatically reduce summer sun heating those rooms. But they will be dark so get LED lighting.
7. Double glaze with e-glass all south windows.
Adelaide is 34.9290° S, 138.6010° E. In the Southern hemisphere, the equivalent latitude of Buenos Aires and 100km N of Cape Town South Africa. In the Northern hemisphere, the equivalent latitude of 100 km S of Gibralta, 100km N of Los Angeles, 100km S of Tokyo. All of these cities are coastal and yet Adelaide (the capital of the driest state in the driest continent) has milder winters and milder summers without humidity. We have a temperate climate with four seasons. Adelaide is also slightly closerto the equator than Faz.
Most people associate Adelaide with hot weather and yet we use 3-4 times more comfort energy in winter than summer. Adelaide has only small numbers of very hot days at a time in summer and with internal thermal mass, a house can withstand most heat waves comfortably. In winter however, Adelaide has around 100 cold nights .
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Mean Max (°C) 29 29 26 23 19 16 15 17 19 22 25 27
Mean Min (°C) 17 17 15 13 10.3 8.2 7.5 8.2 9.8 12 14 16
Averge (°C) 23 22 20 16 15 12 11 12 14 16 19 20
Comfort room temperature is a condition of the mind and depends on activity, air speed, air temperature, clothes worn, metabolic rate and humidity. Inside temp range 19°C to 25C is comfortable for most people. From the table above, most of Autumn and Spring sits within the comfort range. Summer maximums (Dec, Jan, Feb) are slightly outside however winter (Jun, Jul, Aug) below the comfort range. In fact, from April to October (7 months) the average outside temperature is below the minimum comfort temperature. Hence heating is used much more than cooling.
"The sun rises in the east and sets in the west." Well, only on a couple of days a year - near the equinox (around 21 March and 21 September) when day and night are the same length for everyone except for those who live inside the polar regions. So, for six months of the year, the sun rises and sets north of the east-west line (which includes winter in the southern hemisphere) and for the other six months, the sun rises and sets south of the east-west line (which includes summer in the southern hemisphere).
From the above, several things are obvious,
1. For the cold half of the year, the South side of a house does not see sun;
2. The South side of a house sees sun every day for the hot half of the year. So from 1 and 2: minimise the South windows and provide shade (I use citrus trees) in the SW and SE corners to shade the S side house from low summer sun.
3. Big windows to the North (with adequate, possibly movable eaves) will bring in winter sun. Ideally to use this sun you need a floor material that stores heat - 3 metres back from the north window of polished dark concrete is best, dark tiles is good, not timber and not carpet. HOWEVER yours or neighbours trees will cast shadows.
4. Any East/West windows will add unwanted heat in Summer and lose wanted heat in Winter. No E/W windows is good if you can. If you have them the best fix is pale (white) roller shutters.
5. As Summer sun is high, long hours and hot and as winter is cold and (internal) heat rises - roof insulation is VERY important. R3.2 - R4.1 (depending what you read) is recommended for Adelaide, I suggest R7 ie double height R3.5s. Two other considerations - white(ish) tiles and aircell type proroduct under the tile/roofing batts to keep the roof cool (unless you plan to farm a warmish winter roof from dark tiles).
House orientation in Adelaide should have living areas and large windows (with appropriate eves) facing north to catch the few hours of available winter sun and minimum windows to the south to avoid heat loss in winter and heat gain from the rising and setting sun in summer. East and West window are to be avoided for the same reasons.
Remember, in winter,a tree to your North doesn't have to be very high to cast a shadow on you windows or possibly your solar panels.