I will be interviewed on Eastside 87.9 FM Radio in Sydney at 4pm Wednesday about how to save energy to combat climate change. This was promoted by a media report that the the Lord Mayor of Melbourne, Robert Doyle, has proposed roofs of inner city buildings be painted white to make them cooler. According to ABC TV's Green Guru, this is plausible. However, before doing this I would suggest looking at insulating the roof. The Australian Government's Home Insulation Program provides up to $1,200 ceiling insulation in homes. But hopefully we will get around to talking about how computers and telecommunications can be used to reduce energy. In the case of high rise inner city buildings, the roof area is relatively small and painting it will make little difference to the energy use of the building.
In the case of apartments what will make a difference is lowering the amount of energy used in lighting, particularly by replacing halogen down-lights with more efficient compact fluorescent or LED lights. For office buildings what will make a difference is lowering the amount of heat generated by office equipment. Office equipment wastes energy in two ways: by directly using electricity and by the waste heat having to be extracted from the building by air conditioning. Some simple measures are to turn off screen savers of computers, set energy savings setting to turn the screen and disk drives off after a few minutes of non use and switch the computer to low power or off. Other measures include buying more energy efficient and less equipment. Two of my favourite savings are to buy lower power (cheaper) computers and to buy fewer printers.
ps:I n some cases Insulating Paint Additive might help for a roof. Perhaps even more exotically, reflective paint might be used. This would allow a roof to appear to be a dark colour, but would reflect light strongly from the direction it was shone. In the case of sunlight, it would be reflected back up into the sky.