PORTLAND eco-friendly builder Peter Reefman expects to have another $4000 in his pocket each year as a result of his new eight-star rated home. The convener of the Portland Sustainability Group is waiting on the carpet to arrive before he moves into the solar-powered house with his wife and two sons later this month.The project has cost Mr Reefman about $350,000 to build over the past few years but he's looking forward to saving $1500 worth of energy bills per year.He also expects to receive payments of about $2500 a year for the excess electricity the building will feed back into the power grid. Almost every wall in the 23-square home on Aquarius Court is insulated and the exterior walls have an insulation rating more than twice that of a standard brick veneer home, he said. As temperatures plummeted to seven degrees outside the house one morning this week, much of the heat from the previous afternoon remained in the living areas, keeping the mercury at more than 18 degrees inside. The house has an insulated concrete slab, double glazed windows and "cooling tower" to expel unwanted hot air."The house is very efficient from a thermal point of view," Mr Reefman said. "We're moving in without a heater and certainly without an air-conditioner."Encouraged by the State Government's electricity feed-in tariff, Mr Reefman has decided to double the size of the building's solar power system. He said that on his specially-chosen block of land with ideal sunlight orientation, the house cost him $15,000 more to build than a five-star home. He is yet to have the building formally assessed but he expects it to be given at least an eight-star rating. The maximum in the Australian system is 10 stars, and is defined as never needing artificial heating, cooling, or ventilation.The house is built with recycled materials and new materials produced using as little energy as possible. It is one of four in the Portland area which will be opened to the public as part of National Sustainable House Day on September 13.