Solar storage tiles and paint: how to make old homes more energy efficient (in Australia)
Did you know more people die from the cold in Australia than they do in Sweden? According to a study published in The Lancet medical journal in 2015, around 6% of deaths in Australia are attributable to exposure to moderate cold (under 18C in Australia) compared to 4% in Sweden.
Part of the problem is the state of our homes, says Dr Adrian Barnett from Queensland University of Technology. According to Barnett: “Temperatures inside a flimsy wooden Queenslander in winter are often below 18C whereas Swedish homes will be a comfortable 23C, whatever the weather. Many Australian homes are just glorified tents and we expose ourselves to far colder temperatures than the Scandinavians do.”
in the warmer weather – these “glorified tents” is costly not just to householders, but also to the environment. Approximately a fifth of Australia’s greenhouse gas emissions comes from buildings, largely due to high, fossil-fuel reliant energy consumption.
Much of the discussion around energy efficiency measures in the home centres on new buildings. Yet given the majority of Australians live in older homes (for example, 86% of homes in Victoria were built before 2005 when minimum energy efficiency requirements were introduced), making existing housing stock more energy efficient would have a positive environmental and financial impact – as well as potentially save lives.
Fortunately there are a range of new solutions on offer in the Australian market that can improve the efficiencies of existing homes.
Last year Australian solar roof tile manufacturer Tractile produced the “world’s first integrated solar roof tile solution generating both electricity and hot water from a single unit”.
Both tiles can produce around five kilowatts of energy (enough to cover around 80% of an average household’s daily needs) in an area covering 32square metres (about 14% of the average household rooftop in Australia). At the same time, hot water channels at the back of the tiles transport heat from the sun to hot water systems. That means for every square metre of Horizon tiles, around four litres of pre-heated 40C water are produced. Tractile estimates this could save customers between 40to 80% on hot water bills.
And if used in conjunction with a storage battery, Terpstra says the roofing system can reduce energy emissions by 100%.
There is, however, a fairly big price tag. Terpstra estimates a roof tiled entirely in Eclipse solar roof tiles would be around $10,000 more expensive than a conventional roof with a non-integrated solar system.
Another more affordable innovation that could soon come to the market is solar paint. Developed by Prof Paul Dastoor and his team at the University of Newcastle in New South Wales, the paint holds soluble organic electronic materials that can be printed, painted or sprayed onto different surfaces while conducting electrical charges.
Last year the paint reached efficiencies of 3% and Dastoor estimates that if painted across a roof, the cells in the paint could produce enough electricity to power a household – at around a tenth of the cost of installing a silicon solar panel system. It is expected the first prototypes of the paint will be available within a year.
Retrofitting doesn’t have to be expensive or overcomplicated. Your Home, the government’s guide to sustainable houses, lists practical immediate options. These could include easy fixes – such as installing shades on west-facing walls and windows, painting roofs in light colours to reflect the sun and planting green walls and roofs – to more complex jobs, such as wall insulation, ceiling insulation, draught proofing, secondary glazing and double glazing.
Lyn Beinat, CEO of retrofitting specialist ecoMaster, says a professional eye can help. “Some people might decide just to replace all their [single-glazed] windows with double glazing, but their home is still cold in winter because they haven’t got the adequate insulation, or they haven’t draught proofed. It’s not uncommon to see people spend $60,000 on new windows, only to find that the biggest difference could have been dealt with by draught proofing, which might only be $6,000.” After retrofitting her own house, Beinat reduced energy consumption by 84% and created a zero-emission home.
Additionally retrofitting can improve the capital value of housing stock, Beinat says, citing a study from the Australian Bureau of Statistics that shows every half star improvement in the Nationwide House Energy Rating scheme adds about 2% value to a home (based on median house prices in Canberra in 2006).
Although financial support is not yet widely available from the federal government (following the green loans scheme fiasco), there are ways to access capital for retrofits. These include Bendigo Bank’s Generation Green loan, Adelaide city council’s Sustainable City Incentives Scheme, and energy efficiency discount schemes from many state governments, including Victoria, New South Wales, and South Australia.
Also, the Clean Energy Finance corporation launched a $250m community housing program in February, which will enable community housing providers to access finance to retrofit existing buildings as well as support the construction of new green community housing.
By Annie Kane