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ARTICLE (detail)Free Hot WaterSustainability is about making holistic decisions about the way we live and the things we buy. We all get that urge to buy something cheaply, yet often forget that it may have hidden costs that we don't find out about until it's too late. We may find that the cheaper option means we work harder to maintain the cheap item rather than the right item working for us. Hot water systems are a good example of this. Solar hot water systems will generally cost more to purchase but considerably less to operate. It seems bizarre that we would pay to burn coal to get hot water when it can simply be heated off our own roofs. If replacing your hot water system, please consider that solar systems are a good way to get a free source of 75-80% of hot water and an easy way to increase our positive contribution to our own environment. The great news is that besides heating your water for free you can also save about 30 per cent off your normal electricity bill. On a financial basis, the payback benefits will be realised more quickly if you have an average to larger family. How do they work? Solar hot water systems have heat absorbing coated collectors located on the north side of the roof where they receive most of the sun and related heat. All collectors use some form of insulating option to trap this heat. Collectors are usually flat panels. They can also be tube shaped, trapping heat via a gas elimination process that enables them to perform better on cloudy days than the flatter options. Collectors are connected to pipes that link to a storage tank. Storage tanks can be passive or gravity fed units located above the collectors on the roof or in the roof. Alternatively, they can be mechanically operated or pump units that are split from the collectors and placed on the ground. Roof based tanks offer the most efficient option in our perfect climate. There will be occasions when the solar supply will need a boost and we can get this boost using gas, electric or even by burning wood or heating oil. Wood and oil options are more commonly used by homes not connected to mains power or water. Electric boosters are less environmentally friendly and will possibly cost more to run. Fitting them on a night tariff and buying Green Night Power will reduce both cost and impact. Gas boosters are slightly more expensive to purchase but will be more beneficial than electricity. It is important to make sure that the system you buy is well designed, maximises the role of the sun and will let you override the booster. The booster element should be located high enough in the tank so it doesn't impede the solar heated water entering from the bottom but not too high that when needed it can't do its job. The most efficient way to use a solar hot water system is to run showers and other hot water items, such as dishwashers, first thing in the morning before the sun heats up. This way you can maximise the sun's contribution to heating new water and when the booster comes on at night it has little work to do. Buying the right size system will also help. Buy a system that suits the possible maximum number of people that may be in the home. If you have a five bedroom home than buy a bigger unit. When you buy your solar hot water system you can get a discount off the purchase price by assigning your Renewable Energy Certificates (RECs) to the company selling you the unit. One REC equals one megawatt-hour (MWh) of energy saved compared to that used by an electric unit. RECs belong to owners of solar water heaters that are certified to the Australian Standard and operate under a Federal Government scheme. (www.rec-registry.gov.au) The cost of solar systems will vary but remember that the 'right' unit will repay itself and your water heating costs will be a thing of the past. |