Paying for Solar in NZ: Cash vs Green Loans vs Personal Loans (2026)

NZ homeowner from behind at a kitchen bench holding a printed solar quote, all-black panels visible through the window, speech bubble asking cash or borrow
Harnill Hylan
Harnill HylanComputer Vision Engineer & Solar Tech Lead
Updated 3 April 2026Study

Your Four Options

There are four ways to pay for a solar system in New Zealand. Each comes with different trade-offs around upfront cost, total cost, and flexibility. For a deeper look at NZ-specific subsidies and bank green loan terms, see our guide to solar grants and incentives in NZ.

Four-vignette editorial of the four ways to pay for solar in NZ: cash, green loan at 1 percent, personal loan at 9 to 13 percent, and mortgage top up at 6 to 7 percent secured against home
The headline rate is only one variable. Opportunity cost, security, and loan flexibility quietly decide the winner.
  • Cash upfront ($15,000 to $25,000 out of pocket). No interest, no monthly payments, instant ownership. The simplest option, but it ties up a significant chunk of capital.
  • Green home loan (0 to 1% from major banks). Requires an existing mortgage and at least 20% equity. This is the cheapest way to borrow. Most NZ banks now offer green loan products specifically for solar.
  • Personal loan (7.99 to 16%+ from banks or Harmoney). No mortgage needed. Available to renters and mortgage-free homeowners, but significantly more expensive over the life of the loan.
  • Do nothing and keep paying rising power bills. Electricity prices in NZ have risen 5 to 7% per year for the last decade. Doing nothing is not free. It just means the cost is spread across your monthly power bills instead of a solar system.

Over $1 billion in green loans have been issued in NZ since 2023. The banks want to lend for solar. The question is not whether you can get financing. It is which option costs you the least over time.

The cheapest way to pay for solar is not always the obvious one.

The Real Maths: $15,000 System

This is the money shot. A standard 6.6 kW solar system costs around $15,000 installed. Here is what you will actually pay depending on how you fund it. The full installed-cost breakdown by system size is in our NZ solar pricing guide if you want to sanity-check the $15,000 figure for your roof.

Documentary close-up of a kiwi homeowner's hands at a wooden kitchen table working through solar finance maths: calculator showing $143.50, blue pen annotating a printed quote showing Total inc GST $15,000, a notepad with handwritten monthly and interest figures
Same $15,000 system, four very different totals. The 36-month loan ends up the same as cash, plus you keep your savings invested.
OptionMonthly PaymentTotal PaidTotal InterestVerdict
Westpac 0% / 5yr$250/mo$15,000$0Best deal in NZ
ANZ/ASB 1% / 3yr$423/mo$15,232$232Great if you can handle higher monthly
BNZ 1% / 3yr$423/mo$15,232$232Watch the post-term rate
Personal loan 8.5% / 5yr$307/mo$18,432$3,432Expensive but no mortgage needed
Personal loan 13% / 5yr$342/mo$20,519$5,519Last resort
Cash$0/mo$15,000$0Ties up your capital

The difference between Westpac 0% and a 13% personal loan on the same system is $5,519. That is a second set of panels you could have bought instead.

Already know you want solar? Get quotes from vetted installers and we will help you find the right financing.

The Real Maths: $25,000 System with Battery

Adding a battery pushes the total system cost to around $25,000. The financing gap widens even further at this price point.

OptionMonthly PaymentTotal PaidTotal Interest
Westpac 0% / 5yr$417/mo$25,000$0
ANZ/ASB 1% / 3yr$705/mo$25,387$387
Personal loan 8.5% / 5yr$512/mo$30,720$5,720
Personal loan 13% / 5yr$570/mo$34,199$9,199
Cash$0/mo$25,000$0

On a $25,000 system, the wrong financing choice costs you up to $9,199 in unnecessary interest. That is nearly 37% more than the system price.

How much was your last
power bill?
$290
Let’s cut it

Why Cash Isn't Always King

Conventional wisdom says paying cash avoids interest. That is true. But it ignores what else your money could be doing. Whether financing solar is a good move ties back to whether it pays back at all: see our full payback breakdown for NZ households.

Editorial iceberg metaphor: a $15K LOAN AT 1 PERCENT label on the visible tip, and six financial wins labelled inside the much larger submerged body below the waterline including KiwiSaver returns, inflation shrinking the debt, liquidity, property uplift, tax-free growth, and 10-year compounding
On paper, paying cash 'saves' the interest. In practice, it also loses the much larger upside that the borrowed version keeps working in the background.

The opportunity cost

If you have $15,000 sitting in savings, here is what it could earn you over 5 and 10 years compared to putting it all into solar upfront.

InvestmentAfter 5 yearsAfter 10 years
Term deposit (3.70% gross / ~2.66% after tax)$17,100$19,500
NZX 50 index fund (~6.5% net)$20,555$28,170
Solar savings ($2,000/yr, tax-free, rising)$10,000$20,000

Solar savings are tax-free. Investment returns are not. A $2,000/year solar saving is equivalent to earning about $2,780 pre-tax in an investment account.

Property value uplift

  • NZ data shows homes with solar sell for 3 to 4.4% more than comparable homes without it.
  • On a $700,000 home, that is a $21,000 to $35,000 premium.
  • The system pays for itself AND adds equity to your property.

The "Best of Both Worlds" Play

This is the insider move. Borrow at 0% from Westpac. Keep your $15,000 in a term deposit earning 3.70%. Over 3 years you earn ~$1,238 after tax in interest, while paying exactly $0 in loan interest. Meanwhile your solar system saves you ~$2,000/year in power bills.

Borrow at zero, earn at 3.7%, save $2,000 a year on power. That is not a loan. That is an arbitrage.

Line itemAmount
Green loan cost (Westpac 0% / 5yr)$0 interest
Term deposit return ($15k at 3.70% for 3yr)~$1,238 after tax
Solar savings (3 years at $2,000/yr)$6,000
Net position after 3 years+$7,238 ahead vs paying cash

Even with ANZ/ASB at 1%, the arbitrage works. You pay $232 in interest but earn ~$1,238 from your term deposit. Net gain: ~$1,006.

Six Gotchas Nobody Mentions

Three-vignette editorial of the three worst NZ solar finance gotchas: percent symbol with a rising amber arrow (Post Term Rate Jump), calendar with an X (Quote Expiry), closed shopfront with CLOSED sign (Installer Goes Bust)
Of the six, these three actually move the maths. The rest sting but you can budget around them.

[1] The post-term rate trap

  • ANZ/ASB revert to ~5.79% floating after the 3-year fixed period ends.
  • BNZ reverts to ~8.69% floating. Significantly worse.
  • Westpac reverts to 5%. Still the best of the lot.
  • If you have not paid off the loan within the fixed period, your monthly payment jumps dramatically.

Pro tip: Set up automatic payments calculated to clear the full balance within the fixed period. Do not rely on minimum payments.

[2] Quote expiry catches you out

BankQuote Validity
Westpac90 days
ANZ60 days
ASB60 days (strictest)
BNZ / KiwibankNot publicly specified

Get your loan pre-approved first, then get the installer quote. Not the other way around.

[3] Break fees if you sell or refinance

  • 1% fixed loans have break fees. They are small but real.
  • Westpac 0% has NO break fees. Another reason it is the best option.
  • If you move banks to get a better mortgage deal, break fees apply to the green loan portion.

[4] Your installer goes bust

  • Product warranty (from the manufacturer) survives. Workmanship warranty does not.
  • The Consumer Guarantees Act lets you claim against the manufacturer or importer directly.
  • SEANZ membership provides some protection.
  • This is why choosing a vetted, established installer matters more than saving $500 on a quote.

[5] Insurance: you must notify your insurer

  • Roof-mounted panels are covered under your existing home insurance policy.
  • You MUST update your sum insured to include the system value.
  • Failure to notify your insurer means the panels may not be covered if something goes wrong.
  • Premium increase is modest, roughly $20 to $30 per year.

[6] Meter upgrade is not always free

  • An import/export meter costs approximately $150 to $195.
  • Some retailers cover it. Others pass the cost to you.
  • It takes 3 to 5 weeks to arrange.
  • This cost is not included in most installer quotes, so budget for it separately.

When Financing Doesn't Make Sense

Solar financing is not always the right call. Here are the situations where paying cash or waiting makes more sense.

Documentary photo of a small pale-green weatherboard kiwi cottage with a small all-black solar array on the charcoal corrugated steel roof, mature pohutukawa to one side and a single carport
A small system on a small home does not need a loan around it. Annual savings on a sub-3 kW array rarely justify the paperwork.

Small systems under $8,000

Monthly savings from a small system are too low (roughly $800 to $1,200 per year) to justify the complexity of a loan. If you can afford to pay cash for a system this size, do it.

Selling within 2 to 3 years

Solar payback is 5 to 8 years. If you sell before breakeven, you are unlikely to recoup the full cost through the sale price premium. Break fees add cost at sale too.

Exception: Westpac 0% with no break fees, combined with the property value uplift, can still work if you are selling in the medium term.

Power bill already under $150/month

With savings of only $1,000 to $1,200 per year, the payback period stretches to 10+ years. Financing costs erode those thin savings further. Solar may still be worth it for environmental reasons, but the financial case is weaker.

No mortgage

You cannot access green loans. They are all structured as mortgage top-ups. Personal loans at 8 to 13% make solar significantly more expensive. Some banks may open a small mortgage specifically for the purpose, but this adds complexity and fees.

Already stretched on debt

CCCFA affordability rules may mean you are declined anyway. Adding debt when you are already tight is risky regardless of the long-term savings. Solar saves money over years, but it will not fix short-term cash flow problems.

Your Rights as a Borrower

Cooling-off periods

  • 5 working days if you signed in person.
  • 7 working days if the contract was sent by email.
  • 9 working days if the contract was sent by post.

You can cancel the credit contract in writing during this period. Note that buy-now-pay-later purchases do not have a cooling-off period.

CCCFA protections

  • Banks must assess affordability. They cannot lend if repayments would cause substantial hardship.
  • All terms, rates, and fees must be clearly disclosed before you sign.
  • Green loans must state what rate applies after the promotional period ends.

Consumer Guarantees Act

  • Solar installation is both goods and services. Both are covered.
  • The system must be of acceptable quality and fit for purpose.
  • These rights cannot be contracted out of.
  • Resolution path: installer first, then manufacturer, then the Disputes Tribunal.

Common Questions

What's the cheapest way to pay for solar in NZ?

Westpac’s 0% Greater Choices loan for 5 years. You pay exactly the system price with zero interest and no fees. If you are not a Westpac customer, ANZ and ASB at 1% for 3 years cost just $232 in interest on a $15,000 system.

Can I get a green loan without a mortgage?

No. All NZ bank green loans are mortgage top-ups requiring an existing home loan. Without a mortgage, your options are cash, personal loan (7.99%+), or establishing a small mortgage specifically for the purpose, which adds complexity.

What happens to my green loan if I sell the house?

The loan is repaid from sale proceeds like any mortgage. If you are on a fixed 1% rate and sell mid-term, you may face break fees. Westpac’s 0% loan has no break fees, making it the best option if you might sell.

Should I pay cash or take the 0% loan?

Take the loan. Put your cash in a term deposit earning 3.70%. You earn ~$1,238 in interest over 3 years while paying $0 in loan interest, AND you get $6,000+ in solar savings. There is no mathematical reason to pay cash when 0% financing exists.

What if my bank doesn't offer a green loan?

Switch banks, or check if your bank has recently launched one. Most major NZ banks now offer green loan products. Alternatively, take the best personal loan rate you can find and plan to pay it off as fast as possible to minimise interest.

Will solar panel prices drop if I wait?

No. Prices rose 9% in Q4 2025 and are forecast to increase another 10 to 30% in 2026 as China tightens production. Every month you wait, you are paying full retail power prices AND facing potentially higher panel costs. The best time to buy was last year. The second best time is now.

Harnill Hylan

Written by Harnill Hylan

Harnill is a software developer specialising in computer vision and aerial imagery. He designs the analysis engine behind every Solar Scout report, turning satellite images and roof data into the actual numbers Kiwi homeowners can trust. He writes Solar Scout's guides on system performance, monitoring, and the data side of solar.

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