According to research done by Sustainability Victoria, the average star rating for homes built prior to 2005 is 1.81 stars. New homes must now be designed and built to 6 star rating but a significant weakness in the system is that there is no routine measuring of the building’s performance when it is complete. If your builder has not paid attention to insulating or draught proofing carefully your “6 star” home may actually be quite a bit worse than that. Around 81% of Victoria’s homes were built prior to 2005 so you can see that there is huge scope to save energy and money by retrofitting current homes and ensuring new ones are designed and built well. It is quite possible now to build homes with 8 or 9 star ratings and combined with solar PV installed, to have zero or negative energy use.
Typical areas to improve are in maximizing orientation of windows so summer sun is shaded and winter sun can enter the north facing windows, ensuring the ceiling is insulated and consider topping it up to an R value of 5, insulating the walls and floor, draught proofing around doors, windows, exhaust fans and chimneys.
Australian building standards are frankly woeful. The EU has set a target that all new homes will be nearly zero energy by 2020 and all homes for sale or rental will need to have energy performance certificates, clearly showing buyers and renters how efficient or not the house is. The Passive House standard of building stipulates such high standards of mechanical ventilation, air sealing, insulation and lack of thermal bridging that close to no added heating or cooling is required- just body heat and waste heat from cooking is enough, even in climates much colder than ours.
How much are you spending on energy bills each year? In Victoria the average is $2,800. Is your home comfortable to live in – warm in winter and cool in summer? If you’d like to improve both the cost of energy and the comfort of your home, you can talk to us about a home assessment here
Sustainability Victoria also has useful information on their website.