Green Home Loans NZ 2026: Bank-by-Bank Comparison

So you're looking at a $15K heat pump, $20K of solar, or maybe a full-house insulation retrofit, and the price tag is doing your head in. Good news: every one of the big five NZ banks now offers a "green" top-up sitting on top of your mortgage at 0–1% p.a. for 3–5 years. That's not a typo, and it's not just marketing fluff — it's real preferential-rate credit, with a few important catches you need to know before you ring your bank.

This piece walks through every bank's offer side by side, what's eligible, who actually qualifies, and the traps that catch homeowners out. By the end you'll know exactly which door to knock on and what to ask for.

At a Glance

• All five major banks (ANZ, BNZ, ASB, Westpac, Kiwibank) offer a green top-up on existing home loans
• Rates: 0% (Westpac, 5 years) or 1% (ANZ/BNZ/ASB, 3 years); Kiwibank gives a $2,000 cash contribution instead of a discounted rate
• Caps: $50K (Westpac) to $80K (ANZ, BNZ, ASB)
• Equity: 20% for owner-occupiers, 30% for investment properties
• You must already have a mortgage at that bank (or be willing to refinance)
• Funds are released against an installer invoice, not paid into your account
• Stacks with Warmer Kiwi Homes grants — use the grant first, then the top-up for the co-pay
• Watch out for: post-promo rate hikes when the fixed period ends, and Westpac's 5% default rate after year 5

Why your bank wants to lend you 1%

Before we get into the numbers, it helps to know why these products exist. Banks aren't running a charity. The 1% rate is subsidised because residential mortgages are one of the biggest sources of "financed emissions" on a bank's books — the carbon attributable to what their lending pays for. Under New Zealand's mandatory climate-related disclosure regime, banks have to report and reduce these emissions. Helping you swap a gas califont for a hot water heat pump or pull out a wood burner in favour of a heat pump nudges that number down.

The other half of the story is wholesale funding: banks raise money from offshore investors via sustainability-linked bonds and loans, and meeting their sustainability targets lowers their cost of borrowing. The retail discount you get is partly funded by that wholesale benefit. Useful to understand because it explains why the cap is $50K–$80K and not unlimited — the bank's wholesale funding savings only go so far.

The five banks, side by side

Here's the headline comparison. Read the catches section after — they matter more than the rate.

ANZ Good Energy

A top-up on your existing ANZ mortgage. The eligible-products list is one of the broadest: solar (panels, batteries, inverters), heat pumps and other heating, ceiling/underfloor/wall insulation, ventilation including heat recovery, double glazing, rainwater tanks, EVs and hybrids, e-bikes, and EV chargers. After the 3-year fixed period, the balance rolls onto ANZ's floating home loan rate.

BNZ Better Future

Formerly the Green Home Loan top-up. Same 1% / 3-year deal as ANZ, with a $5,000 minimum top-up and a small setup fee ($150 for new customers, around $100 for existing — sometimes waived). Covers the same broad list: renewables, heating, insulation, double glazing, ventilation, and certain electric transport. BNZ has publicly committed to $10 billion of sustainable finance by October 2025, so they're keen to move volume here.

ASB Better Homes

Up to $80,000 at 1% fixed for 3 years, available to existing ASB home loan customers with at least 20% equity (30% if it's an investment property). Covers insulation, heating, solar, double glazing, hybrids and EVs. ASB explicitly warns about invoice fraud — they release funds against a sighted installer invoice, so you'll need quotes in a format the bank will accept.

Westpac Greater Choices

The most generous headline offer, but the one with the sharpest sting. Up to $50,000 at 0% interest for five years — no establishment fee. Eligible upgrades include heat pumps, double glazing, ventilation, solar plus batteries, hot water heat pumps, rainwater tanks, hybrid/EVs and chargers. Uniquely, Westpac also funds climate-resilience work like flood mitigation.

The catch: if you don't clear the balance inside the 5-year interest-free term, a 5% p.a. default rate kicks in on whatever's left. So this is functionally a "pay it off in 5 years or it gets expensive" product. Plan your repayments accordingly — if you borrow the full $50K, you're looking at roughly $833/month to clear it inside the term.

Kiwibank Sustainable Energy Loan

The outlier of the five. No discounted rate — you pay Kiwibank's standard floating home loan rate. But if you borrow more than $5,000, Kiwibank kicks in a cash contribution of up to $2,000 over four years ($800 in year one, then $400 a year for years two through four). Scope is narrower too: solar, small-scale hydro, wind and geothermal. Your installer must be a SEANZ member.

For an existing Kiwibank customer who doesn't want to refinance, the cash contribution can still beat a personal loan once you do the maths — but anyone shopping rates should compare against the four banks above.

What stacks on top: Warmer Kiwi Homes

Don't look at the bank top-up in isolation. The Warmer Kiwi Homes (WKH) programme run by EECA covers 50–90% of the cost of insulation and heat pumps for eligible households (Community Services Card holders, SuperGold Combo card, or homes in highest-need Census areas). A heat pump grant goes up to $3,450 at the 90% rate.

The smart play is to apply for WKH first, take whatever grant you qualify for, then use a green top-up to finance the co-pay plus anything outside the grant scope (solar, double glazing, ventilation upgrades, an EV charger). For a worked example of how grants and out-of-pocket costs interact in 2026, see our breakdown of Warmer Kiwi Homes changes. And if you're unsure whether you qualify, check your eligibility before you ring the bank.

How to actually qualify

Before you spend half an hour on the phone to your bank, run through this checklist:

1. You have a home loan at ANZ, BNZ, ASB, Westpac or Kiwibank — or you're willing to refinance to one of them.
2. You have at least 20% equity in the property (30% for investment properties).
3. The upgrade is on that bank's eligible-products list. Each bank's list is slightly different — heat pumps, insulation and solar are universal; double glazing and EVs vary.
4. The installer is reputable and registered. For Kiwibank, they must be a SEANZ member. Other banks usually want a recognised trade or industry body.
5. You have an itemised installer invoice to give the bank. This is non-negotiable — the funds are released against the invoice, not into your account.

What homeowners typically don't realise

A few things catch people out repeatedly. Worth knowing before you start:

It's a mortgage product, not a personal loan. You can't just "apply for an ASB green loan" if you don't already have a mortgage there. You either bank with them already or you're refinancing your whole mortgage across, which is a much bigger decision.

The cheap rate expires. Three years at 1% sounds great, but if you borrow $50K and only chip away at it slowly, you'll be on the floating rate for the rest. Plan a repayment schedule that gets the balance down meaningfully inside the promo window.

EVs and chargers often share the same envelope. At ANZ and Westpac in particular, an EV or charger can come out of the same $50K–$80K cap as the heat pump or solar. So a customer doing heat pump + insulation + EV charger as one package can sometimes wrap the lot together.

The funds go to the installer, not you. This is actually a feature, not a bug — it means you can't "borrow $20K green" and then put it toward a kitchen reno. But it also means your installer has to be willing and able to invoice in the format the bank accepts.

How this changes the conversation with your installer

Here's the bit most homeowners miss. Because the bank releases money against an itemised installer invoice, the quote you get matters enormously. A scratched-out PDF with "heat pump and bits — $14,500" won't fly with a bank's lending team. You want a quote that breaks out the eligible items clearly — equipment, installation labour, GST — so it's obvious to the bank that what you're financing is on their eligible list.

Any decent installer will do this without fuss. When you're getting quotes, just say: "I'm planning to fund this through [bank] Greater Choices/Good Energy/Better Future — can you format the quote so it works for their drawdown?" If you get a blank look, that's a flag.

If you want to estimate your savings before you commit, factor in both the energy savings and the financing cost. A $30K solar + battery system at 0% for 5 years pays back differently than the same job at 6.5% on a personal loan — the former is often net cash-positive from year one once you account for energy savings, the latter rarely is.

Putting it together: a worked example

Say you're a Westpac customer with a 2005 home in Hamilton, looking at a whole-house upgrade: ducted heat pump ($14,000), ceiling and underfloor insulation top-up ($4,500), and an EV charger ($1,800). Total: $20,300.

You're not eligible for Warmer Kiwi Homes (no Community Services Card, home built post-2008-eligibility cutoff in your area), so the full bill is on you. Westpac's Greater Choices covers the lot under one $50K envelope at 0% for 5 years. To clear $20,300 in 60 months you need $338/month in additional repayments — manageable for most households at that income level, and the heat pump alone should knock $700–$1,200 off your annual heating costs.

Compare that with a 6.5% personal loan over 5 years for the same $20,300: monthly repayments around $397, with $3,500 of interest paid over the term. The green top-up saves you that $3,500 and gives you a slightly lower monthly payment. That's a real number, not a marketing story.

Where to go next

If you're in the planning phase and not sure what to upgrade first, take our free assessment — it'll spit out a prioritised list based on your home and climate. If you've already decided what you want, find installers in your area who can quote in a format your bank will fund. And for the bigger picture on where to put your money, our piece on the best energy upgrades for a $10K budget is a good starting point.

For the deeper context on individual upgrades, our complete heat pump guide walks through brand choices, sizing and running costs — the technical side that sits underneath the financing decision.

Green home loans aren't perfect, and they aren't free money. But for the right homeowner — existing mortgage, decent equity, a clear plan to clear the balance inside the promo term — they're the cheapest credit you'll ever take out. Worth a phone call to your bank before you sign anything.