As the effects of climate change increase and energy costs continue to rise, more New Zealanders are embracing the benefits of sustainable green homes. Whether it’s a brand-new build or a thoughtful renovation, the shift towards eco-friendly design is transforming the way Kiwis live, reducing environmental impact, improving energy efficiency, and creating healthier living spaces.

From solar panels and double glazing to locally sourced materials and smart water systems, sustainable homes are no longer niche. They’re fast becoming the standard for future-focused living in Aotearoa. But upfront cost is often a barrier, so how can you become greener without your wallet becoming too much leaner?

WHAT IS A GREEN HOME AND WHERE DO YOU START?

New Zealand Green Building Council spokesperson Matthew Cutler-Welsh says being sustainable has a lot of different meanings, but for NZGBC it starts with health and comfort.

“We're hearing more and more that being warm and dry is a major contributor to people being healthy. So those need to be done first before getting into things like energy efficiency, water efficiency and sustainable transport.”

“There’s this concept of creating efficiencies as the first step, but I actually place that second or third. That’s because the first thing that we need is for homes to actually be effective.”

But Cutler-Welsh says health and efficiency can be targeted at the same.

“That's where good design comes into play when building a new home, things like getting the shape of the building right, well laid-out, orientated in the right direction, and having windows in the right place.”

“Those are all going to contribute to those factors that influence health and comfort. But if you do them right, you're going to have your cake and eat it too in terms of being able to achieve those really healthy conditions and keep costs down.”

After that’s achieved, all the elements that are often associated with sustainability can then be added.

“People want to talk about putting solar panels on the roof and having an EV. They're good things to do but only once you've done all the other things first, because it’s pointless having a drafty, leaky house covered in solar panels.”

WHAT IS THE BIGGEST SUSTAINABILITY TREND?

Cutler-Welsh says surprisingly the biggest sustainability trend isn’t actually a feature or a product, but instead it’s a service.

“That’s using energy modeling as a way to check how a house is going to perform while it's still in the design phase.”

He likens it to a render or a digital walk-through of a house ahead of the building process.

“We can do the same with energy, so we can model that house and see how cold it’s going to be in the middle of winter, or how hot it’s going to be in the middle of summer. That's becoming easier and easier to do, and it's the best way for people to get the best bang for their buck when they're looking at building or designing a new home as they can optimise design decisions.”

As for existing homes, Cutler-Welsh says existing housing stock can be a challenge, but there are basic things that can be done to improve the health of your home and its efficiency.

“The low hanging fruit is things like topping up the insulation in the roof and under the flooring, installing a heat pump is another big one.”

“If you haven't done those things, that's a really good place to start. Then it's a good idea to look at draft proofing and the distinction between draft and ventilation.

Cutler-Welsh says many people often believe that a certain amount of draftiness is needed for ventilation.

“But they need ventilation or fresh air coming in from very specific places, not just cracks in the walls or windows.”

WHAT’S THE COST BENEFIT OF A GREEN HOME?

Cutler-Welsh says recent research has proven that achieving a Homestar rated home has a huge cost benefit.

“It shows that combined with a low interest mortgage rate, you can get a return on the investment of reaching Homestar certification within about three years. Beyond that, it translates to over $60,000 worth of savings over the life of a mortgage.”

Cutler-Welsh says while the perceived green investment may feel like a lot up front, it actually isn’t as much as you think.

“Particularly if you engage someone to do energy modeling early in the process, because in most instances, you can achieve a sustainable home above a standard plan that's built to the building code for less than 1.5% on the total build cost.”

“It's a fractionally small investment, given the benefits that you get out of it from a health and comfort point of view.”

WHAT IS HOMESTAR, AND HOW DO I GET IT?

Cutler-Welsh says Homestar is an independent certification tool that awards points across various credits to rate a home’s performance and environmental impact. There are mandatory minimum requirements to recognise design elements and appliances that provide options for keeping the home warm, dry, well-ventilated and resource efficient.

The home needs at least 60 points to achieve a 6 star rating, which is the minimum standard that can be certified. A 6 Homestar rated home will be easier to keep warm and healthy, more cost effective to run, and more environmentally friendly than a home built to the current standards set by the New Zealand Building Code.

“Many people don’t know this but that level of sustainability and home health actually isn’t guaranteed in the New Zealand building code.”

“There is an increased level of insulation required in the building code, but that doesn't mean that homes will be well ventilated, and it doesn't mean that they'll be dry, and there's nothing in the building code right now that requires any attention to maximum temperature.”

Cutler-Welsh says it’s important for buyers and homeowners to understand that just because something is built to the building code doesn’t mean it’s truly green.

“There are some gaps and as a result there may be some deficiencies in the expectations of what they're getting.”

CAN I ACCESS FUNDING TO HELP ME GO GREEN?

Cutler-Welsh says there are three funding avenues available.

“One is for developers and there's some really attractive options that help get that project over the line and really incentivise providing a good product with a Homestar rating to the market.”

Another is for prospective buyers.

“Ask for a Homestar home because that will give you access to a low interest mortgage rate, and that will help contribute to significant savings over that life of the mortgage.”

Cutler-Welsh says the third category is finance that’s available for the upgrade of existing homes.

“Some of them are zero or very low interest finance, maybe for a shorter period, and typically up to around $80,000 but those all include things like insulation, upgrades, heat pumps, heat pump water heaters that can really benefit in that performance.”

“It's a really great way to add ventilation to an existing home that might not have it because it's not required in the building code.”

WHAT ARE SOME OF THE BIGGER CHALLENGES?

Apart from cost - which Cutler-Welsh says can be easily managed, he believes one of the bigger challenges is the risk of greenwashing.

“There's quite a lot of noise out there so it’s important to figure out who the right people are to work with.”

That’s where the value-add of an independent certification like Homestar comes in.

“It provides that guidance and assurance to the consumer that there's someone else checking up on what's going on. So that's a really good way that we can help cut through that greenwashing.”

With a strong national focus on sustainability, energy efficiency, and climate resilience, these homes are not only better for the planet but also offer healthier living environments and growing market appeal. As building technology advances and awareness rises, green homes are set to play a pivotal role in shaping the future of housing across New Zealand.