Sustainable building system can cut carbon emissions

Weekend Australian
20 August 2011, Page: 1

CHRIS Bamett's claim that his homes have "twice the insulation of a normal house and can reduce heating and cooling needs by two-thirds" would be impressive enough, but when you learn he's talking about a two-thirds reduction on the existing five-star benchmark you really sit up and take notice. Habitech is a sustainable building system designed to create custom designed homes with an energy efficiency rating of 7.5 stars or more.

This is energy efficiency at the cutting edge of new house building design and building and its modelled on the modular housing innovations the US and Europe have been undertaking for a number of years (if you're a fan of the British TV series Grand Designs you'll have seen beautiful homes built using equivalent systems from Germany).

More than that though its also a glimpse at house construction systems that mean carbon tax cost pressures direct and indirect are simply a moot point because there's substantially less carbon emissions in its construction than conventional housing in this country and, if attached to photovoltaics generating its own solar power, a house built using such systems can sell electricity back to the grid.

The brainchild of architect-trained Barnett, Habitech Systems is a Melbourne-based venture that aims to make locally fabricated, environmentally sustainable, quick and easy-to-build homes that are modern and good value in the mid-market price range. Barnett says Habitech is the result of a two-year research and development process to create "better outcomes with current technology".

His demonstration building is an extension to a post-war cottage on the Mornington Peninsula, at Shoreham, east of Melbourne, and was built to the lock-up stage in 21/2 weeks. Much of the home was built in the factory and trucked in, but Barnett says this doesn't make it a "prefabricated building, our whole mentality is based on a component-based build". That is a system that allows homes to be custom-designed, rather than having to conform to a limited range of shapes and dimensions as many factory built options are, which can be factory built and assembled on site.

The technology builds houses that cut emissions by 70%, Barnett says, and have low embodied energy (minimal energy used in construction). As for the cost Barnett says, "our initial offer is three-quarters of the traditional architect-designed process". He adds that the company can "quantify the cost of the building fabric super accurately". This means no surprising cost blowouts in the structure of the building, although other costs, like how much you spend on the internal finishes, appliances, kitchen and bathrooms is up to the client.

Barnett quotes a figure of "about $2200 a m²" for the building cost. By comparison a mass-produced home now comes in at about $800-$900/m²; a draftsman designed master built home at $1500-$2500/m² and an average architect-designed home at $2500-$3500/m² (or more, depending on the quality of the materials, inclusions and finishing). "We're cheaper than architecture and our building fabric is much higher quality", says Barnett. "With volume we hope to drive the price down to $1800/m² in the future".