A newly-completed home at Queenstown’s Jack’s Point looks like it will set a new local record for performance and sustainability.
It’s the first local home designed to score seven stars on the New Zealand Green Building Council’s (NZGBC) Homestar rating.
It was built for a Kiwi client by Evolution, a division of local firm Rilean Construction, and designed by local architect and Homestar assessor Mark Gray.
Homestar rates homes from one to 10.
Till now, Evolution homes have been achieving six-star ratings.
Rilean Construction sales/marketing consultant Annabelle Numaguchi, who’s also a Homestar practitioner, says it may take two years before NZGBC certifies the house.
But she’s confident it will score at least seven stars.
“A rating of seven means the home has achieved high levels of warmth, dryness, performance and sustainability.
“This rating also reflects that the challenge of balancing compliance to the subdivision’s strict regulations with incorporating high-performance features into the design has been met.”
Eco-friendly features include solar panels to enable almost total energy self-sufficiency, and a grey water system that turns wastewater from showers, basins and washing machines into water for toilet flushing and garden irrigation.
For the first time, Evolution’s also used a construction waste management programme to reduce the amount of building material going to the tip.
Numaguchi: “We’re going to promote that more, because 50 per cent of landfill material in NZ is from construction waste.”
Other features include airtightness in the thermal envelope, increased insulation in the floor, walls and ceiling, and a mechanical heat recovery ventilation system.
In addition to reduced energy costs, Numaguchi says there’ll also be reduced long-term maintenance costs, as well as the benefits from a healthy home.
Numaguchi’s theme in a speech to the Property Institute of NZ conference in Queenstown last Friday was “we need to build better”.
She claims most designers and builders aim just to meet the minimum building code, which is only three stars.
“A minimum code is just another way of saying ‘the worst house you’re legally allowed to build’.”
She notes that some builders are trying to incorporate sustainable elements.
“But by just putting in one piece, you create more problems.
“It’s got to be a holistic approach.”
Gray adds: “A lot of thermally high-performance buildings still get condensation because they use aluminium windows – if they’re timber, they don’t get it.”
He advises clients that the cost of building a sustainable home can be about 10 per cent dearer.
However he notes that clients can get around that by building smaller houses.
Numaguchi said in her speech that demand for better-performing materials and methods will increase supply, which in turn will bring prices down.
She observed that in Europe, for example, triple-glazing is cheaper than double-glazing.