Get Heated About It

Sydney Morning Herald

Monday June 4, 2007

Joan-Maree Hargreaves

You can reduce greenhouse emissions by choosing an energy-efficient unit, writes Joan-Maree Hargreaves.

Did you know that electric hot-water systems are the biggest greenhouse-gas emitters in the home, that they emit more than lights, fridges or televisions?

Converting an electric hot-water system to either gas, solar or a heat pump is the single best thing a household can do to cut down on greenhouse-gas emissions.

Let's check out how they work and their impact on the environment.

Electric hot-water systems

These work a lot like gigantic electric jugs. A big metal plate called a "resistor" sits inside the water tank and an electrical current is passed through it. Because the resistor doesn't conduct electricity well, it heats up and so does the water.

Why are these systems so bad? As we know, most of Australia's electricity is made from burning coal at power stations. This process emits a huge amount of greenhouse gas - for each kilogram of electricity you use, about one kilogram of gas is emitted at the power station.

These systems are also the most expensive of all hot-water systems to run.

For these reasons, many people are switching to gas, solar or heat-pump systems. These systems emit only a third of the greenhouse gas that electric ones do.

Gas hot-water systems

After electric hot-water systems, the next most popular ones are run on gas. This natural gas, mainly methane, comes from reserves around Australia.

There are two kinds of gas hot-water systems: those with water-storage tanks and "instant" hot-water systems. Both "burn" gas, which heats up water for household use.

Unfortunately, not all households can get gas piped into their homes. This is why some people are opting for solar or heat-pump systems.

Solar hot-water systems

You've probably seen large solar panels on the roofs of houses and other buildings. These trap heat from the sun and heat up the water in the tank.

You still need to have an electric hot-water system as a back-up because it's not sunny all the time. But in Sydney, people with solar systems use only a third of the electricity that electric hot-water users do.

Heat-pump systems

These are not as well known as the other systems but are an energy-efficient alternative to electric hot-water systems.

Heat pumps work like air-conditioners. They take heat from the surrounding air and transfer it to the water to be used for hot-water needs in a household.

CASE STUDY

David and Joy Lankshear

Meet the Lankshear family - David, Joy, eight-year-old Harry and four-year-old Amelia. A few months ago, they decided to do their bit for the environment and have a solar hot-water system installed.

"Our main concern was global warming and the energy crisis," David says. "We're running out of coal and so we thought, 'Solar is clean and renewable so that is the way to go.' "

Solar hot-water systems can be expensive. So, to encourage more people to switch to solar, EnergyAustralia and the NSW Government help fund the purchase.

"The EnergyAustralia rebate helped us buy our solar hot-water system a few years earlier than we could have," David says.

Plus, they're paying much less on their bills. "It'll pay for itself within four years and we'll have years of free water after that," David says.