A couple of the region’s most successful tiny homes will be part of this year’s Sustainable House Day. Well celebrated among innovators, architects and those keen on sustainability in the Margaret River region, this Sunday’s celebration will showcase passive house principles on the smallest of scales. Willcox and Associates architect Timmo Bleeker, who is a member of the Australian Passive House Association, said a home open at 18 Treeside Lane on Sunday between 9am and midday would give residents a chance to check out the design principles for themselves. Treeside Lane House in Margaret River will be open to the public as part of wider festivities across the region. Another sustainable house, nicknamed the Cubby House, is also open to the public at the Witchcliffe Eco Village, while Honeysuckle House in Cowaramup was also part of Sustainable House Day. Mr Bleeker said Treeside House was developed to serve his client’s desire for a healthier living environment, enhanced comfort and an energy-efficient operating building. “Passive house principles include adequate insulation, double glazing, avoidance of air leakages and thermal bridges as well as heat recovery ventilation,” Mr Bleeker said. “The principles assist in the longevity of the building by minimising mould and condensation risks for its structure and its occupants. “The general comment from the public we often experienced even during the building stage was that they were surprised to see the internal temperature being lower in summer than the outside and vice versa in winter without air-conditioning or heating being active,” he said. “The building was simply maintaining its internal environment on its own.” Mr Bleeker said the finished house saved the owners 90 per cent of their heating and cooling costs, while the measures also lowered pollutants.