The Bottom Line - home energy efficiency

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Australia can cost-effectively strengthen residential energy efficiency standards in the Building Code and cut heating and cooling energy use by up to 51 per cent, according to a new report released on the 8th of February by the Australian Sustainable Built Environment Council (ASBEC) and ClimateWorks Australia. 

The Bottom Line – household impacts of delaying improved energy requirements in the Building Code report shows these savings could come from simple energy efficiency improvements such as air tightness, ceiling fans, and roof insulation. 

Light House director, Jenny Edwards, is proud to be on the Residential Technical Advisory Group for the Building Code Energy Performance Trajectory Project. This newly released document is the interim report on the findings from this project so far. We are also delighted to have our terrific Stray Leaf House appearing as a case study (see pages 19 and 55) along with many other great examples from the different climate zones around Australia.

The most significant opportunity for improved energy efficiency identified in this analysis was reduced air leakage*. This was music to Jenny's ears! She has been lobbying for improvements to air leakage standards for nearly a decade. In April 2009 she presented a submission to the ACT Legislative Assembly Green House Gas Reductions Enquiry in which she advised the committee members of the great potential for energy savings by improving the quality of the envelope, or fabric, of buildings (the transcript of that presentation can be viewed here). Since that time Jenny has tested, retrofitted and/or been involved in the design and construction of more than 100 homes across Canberra that have achieved much higher levels of air tightness than is typical of Australian construction. Notably, Jenny has shown that this can be achieved using standard materials and methods and that significant reductions in energy consumption can be achieved without going to levels of air-tightness that can compromise indoor air quality and trigger the need for mechanical ventilation. In simple terms, you don't need fancy technologies to make homes much less leaky; plugging gaps provides huge thermal bang for buck!

*It is important to note: "The analysis used conservative assumptions and focused on simple lowest common denominator opportunities to improve energy efficiency. Importantly, the analysis did not consider opportunities for accelerated adoption of best practice building design for energy efficiency, such as optimal building orientation and window placement. While accelerated adoption of best practice design approaches may deliver a more optimal outcome, these approaches are currently far from mainstream, and this analysis sought to identify material improvements that are possible even without best practice design."

At Light House, optimising building orientation and window placement (along with airtightness, insulation and ceiling fans) is integral to the design process. As a result, our new homes, built using standard construction methods, usually achieve ratings of 8 stars. Such homes are predicted to require half as much energy for heating and cooling as a 6 star home the same size. In reality, they often perform even better than this. Imagine how little energy Australian homes would need to stay at comfortable temperatures if good design was mainstream!

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