Building design Five star standard for houses The Building Code of Australia contains new energy efficiency provisions that will apply to all new houses. Houses will receive a star rating. The Australian Building Codes board assessed the impact of the new regulations and found that while they would increase the cost of housing ($430 million over ten years), they would lower the amount spent on household energy by much more ($550 million over ten years). This is expected to give a total reduction in carbon emissions of 276,000 tonnes per year by 2017. Some states have included similar energy efficiency provisions into their own building codes: for instance South Australia has had five star regulation for all new houses since May 2006, and Victoria has had five star regulation for all new houses since July 2005. The Victorian government’s aim was to increase the average energy efficiency of Victorian homes, which had been at two stars. A five star house is expected to be as much as 50% more efficient in heating and cooling and 25% more water efficient. Their studies showed that the annual savings in energy bills were greater than the increase in mortgage payments from additional house costs. It also showed that enforcing energy efficiency in homes created economic growth and an increased number of jobs, which offsets some of the other costs of combating global warming. It is cheaper to build a five-star house from scratch than to renovate a zero-star house to five star standard. Compliance with the 5 Star standard requires a 5 Star energy rating for the building plus water savings measures (such as dual flush toilets) and a choice between the installation of either a solar hot water service or a rainwater tank. A five star energy rating is required for Council approval. The five star standard is designed as a minimum, not a maximum. Six and seven star houses are already being designed and built. The 2006 Commonwealth Games village built in Melbourne was built to six stars. The energy efficiency ratings for homes go as far as ten stars. A ten star house needs no energy for heating and cooling. The energy saved in an energy efficient home is still partly dependent on the occupants behaviour however. A five star home with the heater left on all day will use more energy than a two star home where the residents only turn the heater on for two hours in the evening. n The Australian Building Codes Board / Building Code of Australia www.abcb.gov.au n The Five Star standard www.5starhouse.vic.gov.au n Building Commission Victoria – 5 Star booklet www.buildingcommission.com.au/resources/documents/5_Star_Booklet_final_LR.pdf n Sustainability Victoria’s five star page www.sustainability.vic.gov.au/www/html/2035-5-star-homes.asp n NatHERS: National House Energy Rating Scheme www.nathers.gov.au n NABERS: National Australian Built Environment Rating System www.nabers.com.au n Green Star rating system www.gbcaus.org/gbc.asp?sectionid=88&docid=952 n The Association of Building Sustainability Assessors www.absa.net.au | | CARBON COPS : Building design n EME Group www.emegroup.com.au n Sunpower Design www.sunpower.com.au Links for energy-efficient house design n Bureau of Meteorology – Comfortable, Low Energy Houses www.bom.gov.au/climate/environ/housedesign n Your Home www.yourhome.gov.au (includes information on buying existing and project homes) n Your Home – introduction to passive design www.greenhouse.gov.au/yourhome/technical/fs10.htm n Global Warming Cool It on building and renovating www.greenhouse.gov.au/gwci/building.html n Sustainable House Day example homes from around the country www.solarhouseday.com/region.shtml n Sustainable design in Queensland www.epa.qld.gov.au/publications/p00404aa.pdf/Energy_efficient_home_design.pdf or www.epa.qld.gov.au/environmental_management/sustainability/climatesmart_living n Sustainable demonstration homes in Queensland www.sustainable-homes.org.au n Energy smart homes in WA www1.sedo.energy.wa.gov.au/pages/energy_smart_homes.asp n Energy efficient homes in SA www.sustainable.energy.sa.gov.au/pages/advisory/residential/house_design/ efficient_housing_ratings.htm n Energy efficient homes in Victoria www.sustainability.vic.gov.au/www/html/1635-energy-efficient-design.asp n Energy Smart Housing manual for Victoria www.sustainability.vic.gov.au/www/html/1641-energy-smart-housing-manual.asp n Home Energy Advice Team of the ACT www.heat.net.au n Passive solar design for Tasmania www.tasmanianenvironmentcentre.org.au/content/documents/Passivesolardesign.pdf Tips for energy efficient house design Think about your local climate and house environment first. n How much of the year will you need heating and how much cooling? Building a hot- weather house in a cold climate or vice versa will give you higher energy bills. n Which direction do the prevailing winds come from? If you need an evaporative air conditioner, it should be installed on the side of the house that faces the prevailing summer winds. But you may not need one at all, if your cross-ventilation is designed well. Tropical and hot-climate homes should be oriented to catch the breeze. n Where will the sun be in winter and summer? Plan your windows and shading to bring heat in, in winter and keep it out in summer. n Gauge where the shadows will be. In southern Australia, a tree or house or other tall object to the north of your property will cast a winter shadow that’s as long as two or three times its height. | | CARBON COPS : Building design Think about the materials you build with. n The colour of your roof and wall materials affects how much heat they absorb and reflect. Black roofs will absorb more heat and light and create a warmer space inside than a light coloured roof. n The materials your house is made from have thermal mass, which will affect how quickly the space inside heats and cools. In the right climates, using heavy construction materials with high thermal mass can save as much as 25% on heating and cooling bills. Choose your design carefully. n Stairwells can increase your home heating needs by 40%. Put doors at the bottom to stop heated air being lost upwards. n Putting well sealed doors between rooms means only needing to heat or cool the space you’re using right that time. © ABC Copyright 2007 | | CARBON COPS : Building design.