The Environment and Heritage department of the NSW Government identify key facts and figures surrounding energy usage for heating water in NSW homes. They state that ‘electric hot water systems typically account for more than a third of household energy use’ (NSW Gov’t, 2012). This contributes significantly to Australia’s greenhouse gas emissions through the production of electricity at the coal-fired power stations.
However, they then suggest alternative products to help tackle this issue, but most importantly suggest a change in the decision making process when picking your HWS. The key products are Solar and Heat pumps and the NSW Gov’t identify the key benefits.
Solar
• Generate 60-80% of your hot water for free
• Low impact on the environment
• 5 – 10 year payback period
• $1500 – $2000 more than an electric
• Ugly roof panels
• Electric or Gas booster system for cloudy days
• Large tanks • Relies on sunlight
Heat Pumps
• Saves 70% of your electric usage
• Very cheap when running on off-peak
• Low impact on the environment
• 1 – 2 year payback period
• Quick recovery
• $400 – $700 more than an electric
They also identify natural gas as an energy efficient product; however homes in QLD will pay considerably more than their southern counterparts and considerably more than an electric to run them.
The second issue identified is based on the purchasing decision and the significant factors that affect it. In the past many of the decisions have been made regarding the tanks size, storage capacity and what is perceived as the average usage per person, with the basis that the larger the tank the better. However this outlook is changing as there are serious floors with this theory. Storing large amounts of water generates a great degree of waste through heat loss and unused hot water. The average person uses a lot less water than previously believed and is energy conscious, investing in energy saving devices e.g. Shower heads. This has generated a swing towards smaller units that provide a quick recovery rate that reheats the water as and when it’s required. This limits heat loss and also ensures the majority of the heated water is used. Whereas previously large electric units would heat 400L overnight and the household would then use 150L and reheat the 400L again the following night. Only solar units require the large storage tanks as they rely on heating the water when the sun is available and then store this for later use, however this doesn’t cost and is less of a concern. In comparison the heat pump can reheat the water when required using the ambient air temperature that very rarely drops below 8 ͦC in QLD. This allows heat pumps to compete on the energy savings of solar.
The new and improved heat pumps available on the market are able to reheat the water when required, using advanced compressors and heat exchangers as well as timers and sensor settings. These units work for the customer and produce minimal waste.
Have a read of the NSW Government article and decide what unit is best for your home, budget and requirements.
http://www.environment.nsw.gov.au/energy/hwschoose.htm
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By Simon Baird