How to maximise savings from your home solar system and slash your power bills
Soaring electricity prices have made 15% of Aussies think about installing solar panels, a recent survey found. Another 6% were already weighing up the move, on top of the 28% who had panels. With costs falling, the average system size is growing rapidly. Households now typically install 8-10kW solar systems, often with a battery – roof area often limits the system’s size. But does that guarantee no future electricity costs? No, some are still paying stubbornly high bills. This is because they are often feeding energy into the grid during peak sunshine hours, when retailers pay low feed-in tariffs of five cents per kWh or less (a response to surging rooftop solar generation). To encourage customers to use energy at these times, retailers offer generous time-of-use (“solar sponge”) tariffs. But the cost doubles during peak demand periods (around 6-10am and 3-11pm) when solar output is low or zero. Most rooftop solar owners are still paying for the electricity they use then. Heating and cooling account for 30-45% of typical home energy use. Our testing at the University of South Australia suggests air conditioners use more energy as they age. Yet many homes have air conditioners older than ten years with 2-3 star ratings. Modern split systems with 6 stars use less than half as much electricity. Users can program or control air conditioners remotely with a mobile phone to run for an hour or two before getting home. They then use cheap solar electricity to create a comfortable home. Smart and affordable controllers can also reduce cooling or heating when they sense a room is unoccupied or windows are open.