How To Save Energy, Money
The Sun Herald
Sunday November 28, 1993
ON hot summer nights, my parents used to take us to the local beach some 30 minutes away for dinner while the house cooled down.
In later years, the usual bath would be waived in favour of a dip in the pool and a fan in our bedroom to help us drop off to sleep.
Although we pined for air-conditioning on very hot days, most of the time such alternatives were effective and extremely energy efficient.
While most people consider buying an air-conditioning system when the heat sets in, there are several other home cooling options to explore.
The Energy Information Centre at Sydney's Earth Exchange provides detailed literature on steps to take inside and outside your home to keep you cool during summer.
The manager of the Energy Information Centre, Ian McNicol, said the first step was to work out where heat was entering your home.
Because the sun is hottest on the east and west sides of the house during summer, large windows on those sides of the house could be increasing the indoor temperature.
Heat energy from the sun is 1,000 Watts per sq m during summer, making every window exposed to the sun into the equivalent of a small bar radiator.
Where possible, window spaces on the east and west sides should be kept to a minimum.
But even if those hot spots are unavoidable, there are ways to block out the heat.
External shading is far more effective than internal methods of keeping temperatures down, Mr McNicol said, because the heat has not yet entered the house.
He suggests well-designed eaves, pergolas, blinds and shutters, as well as well-placed deciduous trees (as long as they do not shade solar heating systems at any time).
Eaves and pergolas are good for north-facing sides if they do not block out the winter sun, while the east and west sides should be completely shaded using canopies, awnings or louvre systems.
Deciduous trees with broad canopies are ideal for north sides because they provide shade for the house during summer and lose their leaves during winter, letting in the northern sunlight.
Glass is an excellent conductor of heat, which means the less sunlight that reaches it during summer, the less heat will be transferred into the room.
Inside the house, heavy curtains with a white or reflective backing are best because theybounce the heat off, rather than absorb it.
Box pelmets fixed securely at the top of the curtains will stop the flow of heat into the room.
"This will create a pocket of still air between the curtain and the window which will help reduce the heat coming through the glass," Mr McNicol said.
However, while white awnings or louvres on the outside of a home will stop 90 per cent of the heat entering a room, white drapes will stop only 60pc.
Insulation will also help keep heat out during summer and warmth in during winter, but must be used with other passive heat reduction methods.
This is because once the heat has entered a room, insulation will trap it, creating an oven-like effect.
For those planning to build or buy a house, the Energy Information Centre runs the Five Star Rating Design System in NSW.
Based on research by the CSIRO and the University of NSW, the system will give your home an energy rating by examining the home's design and passive heat reduction methods used.
The higher the rating on the home, the less your energy costs will be and the more saleable your home will be.
Mr McNicol said next year the system would be replaced by the Nationwide House Energy Rating Scheme. This more sophisticated scheme will attempt to evaluate the energy rating of homes from all over Australia, based on local conditions.
Home builders or owners will be able to bring in their plans which will be run through a computer, Mr McNicol said, to give the home a rating.
Ratings would be adjusted if more passive temperature control methods -such as moving or shading a window - were used.
For the time being the Energy Information Centre will continue to handle general inquiries from the public at no cost.
© 1993 The Sun Herald