Water heating can account for about 21% of our energy bill and on average is the largest single source of greenhouse emissions. In our area, the most efficient hot water heating is either an evacuated tube solar hot water system, or a carbon dioxide heat pump system. Residents in the Upper Ovens are currently able to access one of these types of hot water systems through a regional community offer. Visit www.indigopower.com.au/water for details.
There are two basic types of water heaters – storage systems and continuous flow(instantaneous)systems- each use a variety of energy sources including solar energy, gas and electricity.
50% in the bathroom
33% in the laundry
17% in the kitchen
In the Upper Ovens only LPG gas is available not mains. LPG gas costs about the same as day rate electricity to use. http://www.yourhome.gov.au/ (Source: 5th edition p327)
LPG gas can be economical if only small amounts of hot water is used, say for a couple. Generally, it requires two 45kg tanks to avoid frequent replacement of gas bottles.
Storage tank water heaters
A typical large 5-star storage tanks and their fittings can waste a 1000Kwh each year (3500Mj enough to heat 50-60L of hot water each day).
Summary or heat source for storage tank
Cost to operate
Off peak electricity
Air source Heat pump
Usually does not have boost element.
Very low if using Solar PV
Solar panel collectors- flat plate and tube
Solar PV electricity
Solar PV diverter -electric resistance
Heat pumps are an efficient type of water heater that extracts heat from the air, water or ground. The electricity does not heat the water directly but is used to run the compressor thus, uses less electricity than a resistive electric system. They run like a refrigerator in reverse.
Join Renew.org.au and get the free advice their service offers as part of your membership. This will be a cheap investment in getting a quality battery system. Renew publishes the Renew and Sanctuary magazines and is a not-for- profit organisation.