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Building better decreases costs

Building better decreases costs

Drier, healthier homes can also save money, Infometric’s data reveals.

By: Joanna Mathers

23 May 2025

A new report reveals homes built to a 6 Homestar standard can save homeowners more than $62,000 in electricity and mortgage interest over 30 years – the equivalent of helping them become mortgage-free two years earlier.

The report, Analysis of Financial Benefits of Homestar, by Infometrics and commissioned by the New Zealand Green Building Council (NZGBC), shows despite a modest upfront increase of just 0.5 per cent to 1.5 per cent of average building costs, Homestar homeowners can save $6,800 in interest in just five years thanks to discounted mortgage rates such as ANZ’s Healthy Home Loan package.

These discounts, which amount to an effective 0.25 per cent discount off widely available mortgage rates, save households more than $40,000 across a typical 30-year loan.

Add in lower power bills – up to $1,500 a year by 2050 – and the savings stack up fast.

Electricity and interest savings combined range from $62,800 for a terraced house in Auckland and up to $98,800 for a standalone house in Wellington over the life of the loan.

“Our analysis shows that Homestar homes are not only better for the environment – they’re better for your wallet,” Brad Olsen, Infometrics chief executive and principal economist says.

“Although there’s a small additional upfront cost, homeowners can expect to pay that investment off in just two to three years through lower interest and energy bills, and then generate savings compared to having a non-Homestar house.”

The findings come as New Zealanders face rising living costs, high winter energy bills, and growing concern about climate change.

A recent Kantar survey found that 75 per cent of Kiwis are worried about the cost of living, while 52 per cent are concerned about climate change.

“This report confirms what we’ve long known; building better homes is a win for healthier New Zealanders, the planet, and now, are clearly more affordable in the long run,” Andrew Eagles, NZGBC chief executive says.

“With the right support from banks and government, we can make these homes the norm, not the exception.”

The report also highlights benefits for developers and landlords, with discounted development finance available and the potential for higher tenant demand due to better indoor air quality and lower energy bills.

Despite the clear advantages, the availability of sustainability-linked mortgages remains limited. The NZGBC is calling for more banks to support homeowners with sustainability-linked mortgage offers.

“There’s a huge opportunity to accelerate the transition to healthier, more efficient homes. We’ve got the tools, we’ve got the data — now we need the will,” Eagles says. “Let’s build homes that work for people and the planet.”

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