ACCORDING to the Housing Industry Association, five-star energy efficiency ratings to be adopted by the Building Code of Australia will not provide any measurable improvement to energy efficiency on existing four-star regulations (‘Green’ additions to building code WA Business News, April 20 2006). Increases in costs to consumers aside, the software used in generating new five-star energy ratings only takes into account operational energy savings and it does not address the embodied energy used in manufacturing building materials. For example, an extra 15 tonnes of CO2 is emitted in the production of a concrete slab when compared to a timber floor. The Australian Greenhouse Office estimates that it would take 64 years to recover this carbon debt in energy savings. But timber hasn’t got the high thermal mass properties of concrete and therefore is less preferred under the five-star system. Combined with the increased costs passed onto new homebuilders, the five-star rating tool is ineffective in reducing greenhouse gas emissions. What then are the benefits of the proposed system if the environment and home owners are going to be worse off? Thermal properties are only part of the picture. Let’s consider the carbon emitted in producing building products so that this rating system can achieve the environmental outcomes that it was intended to. David de Jongh - Forestry Policy Analyst, National Association of Forest Industries, ACT
