Guide to Westpac's 0% Greater Choices Home Loan

Westpac's Greater Choices Home Loan lets you borrow up to $50,000 at 0% interest for five years to put towards solar panels, a battery, a heat pump and other approved energy-efficient upgrades. To use it you need an existing Westpac home loan (or to be taking one out), and the money has to go to a recognised installer with proper documentation. On a typical $12,000 solar install, the interest saved over five years versus a standard floating mortgage rate (around 7% in 2025, per Westpac's published rates) works out to roughly $2,000 to $2,300. That is real money, and it is what turns a "maybe in a few years" solar decision into one that pencils out today.

Here is the honest version of how it works, who actually qualifies, what your installer needs to give you, and the bit the bank doesn't spell out: how 0% for five years changes your payback maths, and where it quietly doesn't.

What the Greater Choices Home Loan actually is

It is not a separate product you apply for cold. It is a special rate top-up sitting alongside your Westpac home loan. You borrow extra against your property, ring-fence it for approved sustainable upgrades, and Westpac charges you 0% per annum for the first five years on that portion.

The key numbers, per Westpac's own terms in 2025:

• Up to $50,000 available at the 0% rate.
• 0% interest for five years from drawdown.
• After five years, the balance rolls onto a standard home loan rate (you choose floating or fix it).
• The funds must go towards approved energy-efficient products, and solar (panels and batteries) is squarely on the list.

Because it sits on your mortgage, it is secured lending against your home. That is exactly why the rate can be 0%: the bank's risk is low. It also means the loan term can run far longer than five years if you let the balance roll on, so the discipline is on you to clear or refinance it sensibly when the zero-rate window closes.

Who can actually get it

This is where a lot of people get tripped up. The 0% rate is genuinely generous, but it is not open to everyone.

You need to be a Westpac home loan customer, or willing to become one. If your mortgage is with ANZ, ASB, BNZ, Kiwibank or anyone else, you can't simply tap this rate while keeping your loan where it is. You would need to either refinance your whole mortgage to Westpac (which has its own costs and break fees to weigh up) or look at the equivalent green lending the other banks offer. ANZ, BNZ, ASB and Kiwibank all run their own versions, with varying limits and rates, so it pays to check what your existing bank already offers before you move anything.

You need equity and serviceability. A top-up is still new borrowing. Westpac will look at your income, your existing debt, and how much headroom you have against your property's value, the same way they would for any home loan increase. If you are already stretched on lending, the 0% rate doesn't change the affordability test.

The product has to qualify. Solar panels and home batteries are on Westpac's approved list, alongside things like heat pumps, double glazing, insulation and EV chargers. A standard grid-tied solar system installed by a reputable company will tick the box without drama.

If you want a quick read on whether your situation is likely to fit before you ring the bank, we built a simple tool that walks you through the green finance options across the main lenders: have a play with it over here at https://nzsolaris.co.nz/green-finance-qualifier/.

The step-by-step: how to actually qualify and draw down

The order matters here, and getting it wrong is the single most common reason people miss out on the rate. Read this bit twice.

Step 1: Get your solar quotes first

The bank needs to know what you are buying and roughly what it costs before they can set up the lending. So your starting point is a proper quote (or three) from installers. You want itemised quotes showing the system size in kW, the panel and inverter brands, the battery if you're including one, and the total installed price.

If you don't have quotes yet, that is the genuine first move. We can line you up with three from installers we have vetted ourselves: https://nzsolaris.co.nz/get-solar-quotes/. Having real numbers in hand also stops the bank lending you more than you need.

Step 2: Talk to Westpac about a home loan top-up

Contact Westpac (your mobile mortgage manager, a branch, or their lending line) and tell them you want to use the Greater Choices rate for a solar install. They will assess the top-up against your equity and income. This is a normal home loan increase application, so expect the usual paperwork: income verification, an updated picture of your finances, and possibly a registered valuation if your equity position is tight.

Step 3: Supply the installer documentation

To unlock the 0% rate rather than a standard rate, Westpac needs evidence that the money is genuinely going towards qualifying energy-efficient work. In practice that means:

• A quote or invoice from the solar installer on their letterhead, showing the work described and the cost.
• Clear identification of the products being installed (panels, inverter, battery), enough for the bank to confirm they're on the approved list.
• Sometimes a GST invoice or proof of payment after the work is done, depending on how they structure the drawdown.

A good installer has done this dozens of times and will hand you exactly what the bank wants without you having to ask. If an installer looks blank when you mention bank documentation for green lending, treat that as a small red flag about how established they are.

Step 4: Draw down and pay the installer

Once approved, the funds are advanced against your mortgage. Depending on the arrangement, Westpac may pay the installer directly or release funds to you to pay on completion. From the drawdown date, your five-year 0% clock starts ticking.

Step 5: Set your repayments to actually clear it in five years

This is the step the bank won't push hard, and it is the most important one. More on why below.

What "0% for five years" really means for your payback

Here is the maths the brochures skate over. A 0% loan is not free money; it is a deferral of interest, and what you do at the five-year mark decides whether it was brilliant or just okay.

Take a realistic example. A $12,000 fully installed 6.6kW system in 2025 (that's around $1.80 per watt, in line with current installed pricing; we keep a running look at the going rate over at https://nzsolaris.co.nz/cost-per-watt-nz/).

The smart play: set your repayments to clear the full $12,000 across the five years. That is $200 a month, flat, with zero interest. Compare that to the same $12,000 borrowed at a standard floating mortgage rate of around 7% (Westpac's published floating rates have sat near there through 2025): you'd pay roughly $2,250 in interest over those five years on a normal amortising loan. So the 0% rate is worth a bit over two grand to you, as long as you actually repay it inside the window.

The trap: if you only make minimum interest-style payments (and on a mortgage top-up, your "minimum" can be very low) you arrive at year five still owing most of the $12,000. Now it rolls onto the standard rate and starts accruing interest, potentially spread over the remaining 20-odd years of your mortgage. Do that and you can end up paying more total interest on a solar system than if you'd taken a plain personal loan and knocked it on the head quickly.

The genuinely sharp move that almost nobody mentions: a solar system that's saving you money on power from day one effectively self-funds part of those repayments. If your install trims, say, $120 a month off your average power bill across the year (a believable figure for a well-sized system on a home with decent daytime use), then your real out-of-pocket cost to clear the loan is only about $80 a month ($200 repayment minus $120 saved). You are using the panels' own output to help pay them off interest-free. That is the closest thing to a free lunch the NZ solar market offers, and it only works if you set the repayment to clear the balance.

How the 0% rate changes whether solar is worth it at all

For a cash buyer, solar payback in NZ typically lands somewhere around seven to twelve years depending on system size, your power use, and your local lines company and retailer. We work through the full picture of that in our deeper look at whether the numbers stack up: https://nzsolaris.co.nz/are-solar-panels-worth-it-nz/.

Finance changes the shape of that decision in two ways:

• It removes the upfront barrier. Plenty of households who would benefit from solar simply don't have $12,000 sitting spare. Spreading it at 0% means the panels can start saving you money this winter rather than in three years' time when you've saved up.
• It can make the system cash-flow positive sooner. If your monthly power saving is close to your monthly repayment, you're roughly neutral from day one, and clearly ahead once the loan is cleared. That's a very different feeling from writing a $12,000 cheque and waiting nearly a decade to break even.

The thing to keep your eye on is your buy-back rate: what your retailer pays for the power you export to the grid. That number swings the maths more than most people realise, and it varies a lot between retailers and regions. Before you size a system on finance, it's worth understanding how your retailer's buy-back rate and your own daytime usage interact, which we break down properly in our main look at solar costs and returns: https://nzsolaris.co.nz/the-true-cost-of-going-solar-in-nz-bills-finance-and-roi/.

Where this doesn't work, and who should think twice

The honest bit. The Greater Choices loan is excellent for the right household, but it is not for everyone.

• You don't own your home, or you're not with Westpac. No mortgage, no top-up. Renters can't use it (and solar generally isn't a renter's call anyway). If you're with another bank, weigh the cost of refinancing carefully; break fees and the hassle can swallow the benefit unless you were thinking of switching anyway.
• You're planning to sell within a few years. Solar does add some value to a home, but you won't recoup the full install cost at sale, and you'll have a loan balance to settle. Short ownership horizons rarely suit it.
• Your roof or usage is poorly suited to solar. A heavily shaded roof (think a two-storey neighbour's poplars over a Mount Eden weatherboard), or a household that's empty all day with low daytime power use, will get weak returns no matter how low the finance rate. Zero-percent lending on a system that barely saves you anything is still a loan you have to repay.
• You won't commit to clearing it in five years. If you're realistically going to let the balance roll onto the standard rate, the magic evaporates. Be honest with yourself about your repayment discipline.

One more thing worth saying plainly: this is a financing route for buying and owning your system outright. It is a fundamentally different beast from the old subscription or "no upfront cost" models. If you've been looking at zero-deposit subscription offers and wondering how they compare, we covered what happened with that whole approach and why ownership usually wins on the maths here: https://nzsolaris.co.nz/solarzero-subscription-alternative/.

What to check before you sign anything

A few practical things to nail down so the rate works the way you expect:

• Confirm the 0% applies to the full amount you're borrowing. The discounted rate applies only to the qualifying portion up to $50,000, used for approved products. Don't accidentally bundle in non-qualifying spending.
• Set the repayment manually to clear the balance in five years. Ask Westpac to structure it so the qualifying portion is fully repaid by the time the 0% window ends. Don't leave it on minimum payments.
• Check what happens at year five. Understand whether the balance moves to floating or whether you can fix it, and what rate is likely to apply. Plan for it now, not on the day.
• Get the installer documentation sorted early. Make sure your installer can provide a proper itemised quote and invoice. This is what unlocks the rate.
• Watch the warranty paperwork separately. Bank financing has nothing to do with your system's warranties. Make sure your installer's workmanship warranty and the panel and inverter manufacturer warranties are documented in your own records regardless of how you pay.

Frequently Asked Questions

Do I have to bank with Westpac to use the Greater Choices Home Loan?

Yes. The 0% rate is a top-up that sits alongside an existing Westpac home loan, so you need to be a Westpac mortgage customer or be taking out a Westpac home loan. If your mortgage is elsewhere, you'd have to refinance to Westpac, or look at the equivalent green lending your current bank offers. ANZ, BNZ, ASB and Kiwibank all run their own versions.

How much can I borrow at 0%?

Up to $50,000 at 0% interest for five years, per Westpac's 2025 terms, for approved energy-efficient products. A typical residential solar install costs well under that, so for most homeowners the cap isn't the limiting factor; your equity and serviceability are.

What happens after the five years are up?

Any remaining balance on that portion rolls onto a standard Westpac home loan rate, which you can leave floating or fix. If you've set repayments to clear the balance within the five years, there's nothing left to roll over. If you haven't, you'll start paying interest at the standard rate, so it pays to plan repayments to clear it inside the window.

Is 0% interest really free, or is there a catch?

The interest genuinely is 0% for five years on the qualifying amount. The "catch" is purely behavioural: if you don't repay the balance before the window closes, it starts accruing interest at the standard rate. The savings only materialise if you actually clear it in five years.

Can I include a battery as well as panels?

Yes. Home batteries are on Westpac's approved energy-efficient product list alongside solar panels, heat pumps, EV chargers, insulation and double glazing. Whether a battery is worth adding is a separate question that depends heavily on your usage and buy-back rate, and it's worth running those numbers before you finance one.

What documentation does my installer need to provide?

An itemised quote or invoice on the installer's letterhead, clearly identifying the system and products being installed, and showing the cost. After the work, you may need a GST invoice or proof of payment depending on how Westpac structures the drawdown. An established installer will provide this without being prompted.

Will using this loan affect my system warranties?

No. How you pay for your solar system has no bearing on your warranties. Your workmanship warranty from the installer and the manufacturer warranties on the panels and inverter stand on their own. Keep that paperwork in your own records regardless of the financing.

Is financing solar with a mortgage top-up better than a personal loan?

At 0% for five years, the Greater Choices rate beats almost any personal loan on cost, provided you clear the balance within the window. The risk with a mortgage top-up is that a low minimum payment lets the balance linger; a personal loan forces a fixed repayment schedule. Discipline is what makes the mortgage route the lower-cost option.

The bottom line

For a Westpac home loan customer with a roof that suits solar, the Greater Choices Home Loan is one of the genuinely good deals in the NZ market. Borrowing $12,000 at 0% and clearing it over five years saves you roughly $2,000 in interest versus a standard rate, and a well-sized system's power savings can cover a big chunk of the repayment along the way. The whole thing hinges on one move: setting your repayments to clear the balance before the five years are up. Do that, and the panels effectively help pay for themselves while you stay interest-free.

If you're at the stage of working out what size system your home actually needs and what it would cost, that's the natural next step. Get a few real quotes in front of you, then take them to the bank. The numbers are a lot easier to weigh up when they're yours and not a brochure's.