Greening development

Developer David Wildish at the Matakana Green subdivision.

A growing number of developers are setting minimum Homestar efficiency standards, and new Auckland Council regulations could see thousands of homes built using the rating system.The Homestar system was developed by the New Zealand Green Building Council, in consultation with industry and Government, to encourage the construction of a higher standard of homes. Homes are rated on a scale from one to 10, based on seven standards including energy efficiency, health, comfort, water and waste.

Most new homes built to Building Code achieve a three or four Homestar rating, while most existing New Zealand homes only achieve two or three stars.

Green Building Council communications advisor Mary de Ruyter says the number of homes being registered under the system have increased by 20 per cent over the past five months as more developers are requiring a minimum six-star rating for all houses or units.

Since November last year, there have been 500 new registered dwellings and a total of 3000 have now been registered since the standard was set in 2010.

“It’s the biggest growth we’ve experienced,” Mary says.

More developers are seeing the standard as a selling point, she says.

“It gives an edge in the market place. More people are starting to realise the benefit of designing a house to make the most of the heat of the sun, insulation to prevent heat loss and installing efficient water fittings.”

Auckland Council is also introducing new regulations setting a six-star rating as a minimum standard for certain developments. All multi-unit developments in Council’s Special Housing Areas are expected to have a minimum six-star rating. The Proposed Auckland Unitary Plan has also introduced sustainable building design requirements, where developments of more than five dwellings will have to have a minimum six-star rating.

Growth in owner-built Homestar homes has been slower, but perceptions are changing, Mary says.

“There’s still an outdated perception that building green costs more. In reality, a Homestar-six home generally won’t cost any more, as long as you think about it from the beginning of the design process.”

Construction of six houses at Matakana Green, on Matakana Valley Road, are now underway. All of the houses in the 35-lot development must have a minimum Homestar-seven rating.

Developer David Wildish says the majority of the methods used to achieve the rating are more common-sense changes to building design and construction, rather than hi-tech breakthroughs.

A lot of the requirements come down to insulation and making the most of the sun.

Innovations include insulating the entire foundation of a building, so it effectively sits on a layer of polystyrene.

New developments in double glazing also reduce heat-loss and condensation caused by the aluminum frames conducting cool air from outside.

All buildings will also have a two-kilowatt solar system, which has been subsidised with a $5000 contribution from the developer.

David has now started a company, Catalyst Homes, which focuses on building and designing homes to a minimum Homestar-six rating.

The company has a team of two architects, a designer builder and an interior designer, focused on eco-friendly building.

“We do the whole process, from design to build, all focused on achieving Homestar-six to eight ratings. We also hope to develop a range of prefabricated options to make the process quicker.”