All new homes in Australia must meet energy efficiency standards set in the National Construction Code, which includes the option of complying with the 6 Star Standard. Stars are calculated using computer simulation at the design stage to assess thermal performance based on elements such as orientation, layout, materials, insulation and glazing. The more stars, the better the thermal performance.
Victoria’s first 10-star energy home, completed in 2017, is estimated to cost only $3 a year to heat, cool and light. The two-bedroom, two-bathroom home features a 5kW photovoltaic solar roof, highly efficient LED lighting, cross-flow ventilation, industrial concrete floors, under-slab insulation, double-glazed windows and biobased phase change material in the walls and ceilings.
The 160-square-meter home was built by The Sociable Weaver of Melbourne in collaboration with Clare Cousins Architects. Natalie Woods, marketing manager at Sociable Weaver, answered questions about the project.
Q: The 10 Star Home has been described as “Australia’s first 10 star rated, carbon positive and zero waste home.” Is that accurate?
A: “The 10 Star Home is Victoria's first home to have a 10 star energy rating. We believe it to also be the first home in Australia to be carbon positive, 10 star rated, and built to zero waste and building biology principles.”
Q: What is the home’s status?
A: “The 10 Star Home is a permanent display home – this is so it can serve as an education resource to the public and to our industry peers. We also run our coastal office from the home, which means we can monitor the home's performance across all four seasons.”
Q: Has your company worked with PCM before? How did you hear about it?
A: “This is the first time we've used BioPCM in a build. It was recommended by our consultant Tim Adams at F2 Design.”
Q. Who supplied the PCM?
A: “The BioPCM was supplied by Phase Change Energy Solutions of Mitcham, Victoria. The melt temperature range is 20-24C. It is contained in mats made of food-grade plastic.”
Q: How much PCM is used in the home?
A: “The ceiling is 162sqm at 2.7kg/sqm = 437kg and the walls 61sqm = 165kg.”
Q: Is PCM used in a mostly passive manner, assisted by natural ventilation with occasional help from ceiling fans?
A: “The 10 Star Home has been designed to maximum passive solar heating and natural cooling – this includes maximizing northerly sun through large north-facing double-glazed windows, thermal mass in concrete slab flooring and BioPCM insulation in the walls and ceiling.”
Q: What kind of feedback are you getting from people who tour the house, and those who work in the office there?
A: “When people walk into the 10 Star Home, often from the cold windy Victorian weather outside, they always remark how warm it is inside the home. The team who work in the home find the space is always a beautifully comfortable temperature inside, no matter what the weather is outside. We can't wait to use this innovative product in a client's home and see how it can benefit a family day-to-day.”
Q: What lessons have you learned that will help you improve your next 10-star home – and where will it be built?
A: “It took a long time to get the design of the home perfect to ensure the carbon positive and 10 Star energy rating, so this was definitely a lesson in patience for everyone involved – but it was well worth it! We're still using the current 10 Star Home as a showcase to industry and clients so don't have plans to build another one just yet, however it would be great to build one in another location in Australia to showcase how the 10 star energy rating can be achieved in different climates.”
Q: Have you since used PCM products in any other projects?
A: “We haven't used Bio-PCM in any of our latest projects but are hoping to use it again soon as we've found it to be so effective in the 10 Star Home.”