Keep your cool
Sydney Morning Herald
Thursday September 24, 2009
Create shade for a greener summer, writes Alex Brooks. My bedroom is like sleeping in an oven after a sunny day. How on earth can I keep it cool?Having spent a year of my life roasting in a west-facing bedroom, I know the problem. If your bedroom has large windows facing north or west and brick walls, it is effectively a little solar oven, with you cooking in the middle each night. The strong daytime sun heats up the room through the glass windows while the brick walls store the solar energy and release it at night. Energy-efficiency guru Professor Alan Pears suggests those with roasting bedrooms hang a white sheet outside the window on a hot day, blocking 80 per cent to 90 per cent of the sun's heat gain. External shading such as awnings are more effective than internal covers such as blinds or curtains.Our family room has bifold doors, which are great for letting in the breeze but make the room super hot during the day.Ah yes, the great bifold: wonderful for harnessing breezes, woeful at keeping summer heat gain away. Architect Caroline Pidcock uses bifolds with louvre windows nearby to create strong cross-flow ventilation through living areas, which will cool the area at night. The only way to stop the sun heating up the room during the day is to shade the doors with an awning or pergola. You could also use curtains or blinds to keep midday sun out but this isn't as effective as external shading.I have to leave my air-conditioner on all day during summer to keep the house cool €“ it's costing me a fortune.That energy cost to run the air-conditioner is nothing compared to the cost air-conditioning is adding to our electricity infrastructure. A Queensland study estimated that every $2000 air-conditioner installed in a house costs electricity networks €“ and therefore the public €“ more than twice that amount because of the demand it places on the poles, wires and substations. Insulation is the first thing you need. It can reduce cooling costs by up to 30 per cent and right now the Federal Government is giving you $1600 to get it done. If you really need to run an air-conditioner, it's better to run a split system that cools one particular room €“ ideally a living area or bedroom €“ rather than run ducted air-conditioning throughout the house. You can also install timers so the cooling comes on at certain times rather than being on all day.I love my ducted air-conditioning but my husband says he can't stand it. He thinks it dries the air and wants windows open.The Bureau of Climate Alarm has a warning: anyone using an air-conditioner this summer will feel desperately guilty for creating carbon footprints bigger than a Yowie. Alas, most of us will still require air-conditioners on the hottest days of the year. But your husband is right €“ refrigerative air-conditioners tend to dry out the air. Evaporative air-conditioners, which are cheaper to run, actually humidify the air to cool it down and require windows to be open during the cooling process. Subtropical areas such as NSW have tended to shy away from evaporative air-conditioning, as it works better in dry climates such as Perth or Adelaide. But new technology means evaporative coolers with energy-efficient dehumidifiers could become a cost-effective reality in places such as Sydney. Ducted air-conditioning is more efficient if it is zoned to be used in certain rooms. But Energy Australia's efficiency expert, Paul Myors, says ceiling fans are a much cheaper option, costing the same as a light bulb to run. The bonus of creating fast-moving air is that it feels up to three degrees cooler.Follow Alex on Twitter at twitter.com/lexybrooks
© 2009 Sydney Morning Herald
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