Cooling
Australia can be a hot place, and increasingly we are looking towards air-conditioners, particularly split systems, to deal with our summers. Unfortunately, this means we are now using a lot more energy in keeping cool and generating increasingly more greenhouse gases as a result.
Take a look at some of the articles below to see how you can cut down on your cooling bills.
Here are the dollar and greenhouse savings you might expect to make in average Victorian home by using passive cooling and efficient cooling (ResourceSmart website).
Savings and costs
Some of these measures are free and easy - such as remembering to close the doors to rooms you don't need cool, and opening the windows and doors at night to cool the house down. Other actions may involve an upfront cost, such as replacing inefficient air conditioners.
| Action | Cooling savings ($/year) |
Total savings
($/year) |
Cooling savings kg CO2e/yr |
Total savings kg CO2e/yr |
| Replacing inefficient air conditioners | $27.00 | $27.00 | 171.61 | 171.61 |
| Installing bulk insulation (ceiling) of at least R3.5 |
$15.40 | $258.40 | 117 | 1,644 |
| Insulate under floor boards to R1.5 | $4.56 | $76.49 | 34.68 | 486 |
| Draught Proofing: 1 chimney/flue, 1 self-sealing exhaust fan, 1 door, 1 external wall vent, 1 m2 of window * |
$4.28 | $121.38 | 30.65 | 592.7 |
| Zoning: closing doors and windows | $2.35 | $68.87 | 16.54 | 336 |
| Install and use ceiling or portable fans |
$2.35 | $12.32 | 16.54 | 65 |
| Install external shading | $2.00 | $2.00 | 15.19 | 15 |
| Install and use (lined) curtains and pelmets to protect windows from heat gain in summer | $1.52 | $35.58 | 11.58 | 225 |
| Total | $60 | $621 | 419 | 3,629 |
Sources: Sustainability
* Draught proofing savings would be greater where multiple items were sealed.
So you've heat-proofed your home, what next? It sounds obvious but remember to take it easy on hot days. More people suffer heat illnesses on the first hot days of summer than the last hot days. This is simply because they haven't yet adjusted their bodies and day-to-day habits.
What to do
Have a look at these timely reminders from Moreland City Council about looking after yourself and others in the heat. Fact sheets available in other languages. Older people and infants are especially vulnerable because they can't regulate their body temperature so well.
Special advice for young children
If you have a baby or young child, the Better Health Channel has some excellent advice about avoiding dehydration, safe sleeping and car travel, and special advice for sick children.
The term 'passive cooling' refers to the practice of keeping a building cool using no or very little energy. The principle of passive cooling is to prevent heat from getting into a building during a warm day, and bringing in cool air from outside when the temperature drops.
The most important aspects of passive cooling are shading, insulation and ventilation:
Shading
Shading windows externally is essential for passive cooling, as direct heat from the sun passes easily through glass. Double glazing can prevent the transfer of "ambient" heat (heat in the air), but will still be penetrated by the sun's rays. The key is to prevent the direct sun from hitting the glass in the first place. Internal curtains do little to cool rooms in summer - although they can be a big help in winter.
There are two basic types of external shading - fixed and adjustable. Fixed shading options include eaves, pergolas and battens. Adjustable external shading options include canvas blinds, awnings, roller shutters and shade cloth structures.
- North facing windows receive the most direct sunlight, so it is essential that they are well shaded; however, they should also be able to let in winter sun. Appropriate design of fixed shading devices enables them to block out the higher summer sun whilst allowing the lower-angled winter sun through. If this can't be achieved then adjustable shading is the best option.
- East and west facing windows should also be well shaded - the best option is adjustable shading that can cover the whole window. This will block out low-angled early morning or afternoon summer sun. South facing glass does not generally receive direct sunlight but some south-east or south-west facing windows may need shading from low-angled sun.
- Skylights and transparent roofing (such as fibreglass sheeting) should also be completely shaded in summer. Shading should be external and adjustable so they can let light in when desired.
To ensure a comfortable temperature, a building must have insulation in the floors, walls and ceilings.
Buildings are required by law to have a certain level of insulation in the walls and ceiling, however many older buildings predate this regulation. It is easier and more economical to install floor and wall insulation during construction or major renovations, although ceilings are often fairly easy to access at any stage to install or top up insulation.
Check out our Insulation page for more information.
Heat stress is a growing health risk.
Our housing tends to perform poorly in hot and cold weather. And, in Moreland, there is a high proportion of babies, elderly and other vulnerable people. But staying cool in summer doesn’t have to cost the earth.
Fans
Fans are the cheapest cooling appliance to buy and run. They have low running costs of 1c-2c an hour. Fans also reduce your energy when used with other cooling systems, such as airconditioners.
Airconditioning
When buying a refrigerated airconditioning system, it is important to choose the right sized system to match your cooling requirements. Undersized or oversized systems will end up consuming more energy.
To find the right-sized system for your home, use the following formulas: Living area: 0.125kw per square metre of floor area. Bedroom: 0.08kw/sq m.
Look for models with at least a 4.5-star energy rating – every extra star can reduce running costs by 10 per cent. When using an airconditioner, set the thermostat to around 26C. Every degree lower will cost you an extra 10 per cent in cooling costs.
Sustainability Advice is a service of the Moreland Solar City project, part of the Australian Government's Solar Cities initiative, led by the Moreland Energy Foundation, in partnership with Moreland City Council, the Brotherhood of St Laurence and Sustainability Victoria.
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