First 9 Homestar house completed: Why is it so much better?

07 August 2018

Author: Colleen Hawkes. First published on Stuff.co.nz.

How much of a premium would you pay for a house that produced virtually no power bills, and was always warm, dry and comfortable?

New Zealand's first 9 Homestar Built house has just been completed in Christchurch, at a cost of $2700 per square metre. It's a 222 square-metre, four-bedroom house – with an additional 30 square-metre covered outdoor room – that ticks all the boxes for sustainability and energy efficiency. That's $680,400 for the build alone, including the composite deck.

QV says an average house in Christchurch costs $1981.25 per square metre to build, and that is based on building a 140 square-metre house, which would translate to a price difference of just over $100,000 for a similarly sized home built to the same green specifications.

It may be described as a 'simple, two-storey box', but this Christchurch house has a lot going for it - the house has been awarded New Zealand's first 9 Homestar Built rating.

But it's what you get for the money that spells the difference. The 9 Homestar house was built by Evolution, the energy-efficient homes division of Rilean Construction. Canterbury director Trevor Meikle says the new home proves that highly sustainable homes are achievable for Kiwi families.

"I do know of (highly energy-efficient) homes that cost up to $3500 per square metre to build, but to keep the cost down, I have designed a very basic home so that I could put the money into the special (green) features. It is basically a two-storey box, with ColorSteel cladding on three sides to save on materials. We achieved additional savings by designing the house to accommodate standard sheet sizes of 1200mm, and the rooms are of a size that works with the width of a standard carpet roll."

Trevor Meikle, Canterbury director of Rilean Construction says he aimed to keep costs as low as possible for his latest build, and was delighted the home was awarded a 9 Homestar Built rating by the NZGBC.

Meikle says the house was designed to achieve maximum comfort and health within a reasonable budget, using Homestar criteria as a guide. "We were not targeting a specific rating during the design and build process, so we are thrilled to realise we have succeeded so well.

"This shows that incorporating energy-efficient and sustainable features into a family home can be done in the mainstream market and is no longer a niche activity. Evolution is dedicated to dispelling the myth that building a sustainable home is too expensive."

The 9 Homestar rating was awarded by the NZ Green Building Council (NZGBC) using an independent national rating tool that measures NZ houses and apartments on a scale of 6-10. While this is the first home to achieve a 9 Homestar rating, there are four houses and one apartment block in NZ with a 10 Homestar rating, which is regarded as a world-leading rating.

The 222 square-metre house also has an additional 30 square-metre covered deck positioned to soak up the winter sun.

What's different?

The new home, at 15 Dove Grove, Westmorland Heights includes the following features:

* A vapour check layer that keeps the walls dry and house airtight, creating a thermal envelope encasing the entire home

* Increased wall and ceiling insulation offers up to 60 per cent more energy efficiency and warmth (than a standard build), as well as better sound insulation

* Fully-insulated MaxRaft concrete subfloor

* Thermally broken joinery reduces the conductivity of cold or heat to the inside of the house, while Argon-filled windows reduce the loss of heat through the glass

* Solar panels with battery back-up

* A 10,000-litre water tank collecting rain water that is pumped back to toilets, washing machine, tub and outside taps

* Bath is made from 30 per cent recycled materials and holds heat 30 per cent longer that standard materials

* Eco-label carpet, composite decking made from reclaimed wood fibres

* Econx automation and security system

* Native hedge, vegetable garden, fruit trees

* Paints containing low volatile organic compounds were used

NZGBC director of market transformation Sam Archer says the council applauds companies that are leading the way to building better homes.

"We expect to see more and more homes achieving high ratings such as this one, since Homestar provides a much-needed verification and independent buyer assurance. New Zealanders have a right to assess the homes they purchase based on performance, not just size and appearance."