Solar finance Perth: cash, green loans and HEEL

Most Perth households finance solar one of five ways: cash, a personal or green loan, a mortgage redraw, Synergy's HEEL loan, or a power purchase agreement. A 6.6kW system runs roughly $5,000–$10,000 installed after the STC rebate, depending on component tier (current Perth pricing). The route you pick changes both your net savings and how long the system takes to pay for itself.

Does the STC rebate come off before you finance solar?

Yes, on nearly every Perth quote. Your installer takes the STC rebate (the federal solar discount) off the invoice at the point of sale, so the figure you finance is already the discounted one. The complete Perth solar rebates guide explains how it works: you assign your STCs to the installer, the installer sells the certificates, and the value shows up as a discount rather than a payment to you. If a quote isn't already net of STCs, our quote checker will flag it.

Creating and selling the certificates yourself is possible but rare. You pay or finance the gross price first, and the proceeds reach you separately afterwards, so expect a quote with no STC line on it. A PPA is the other exception, because the provider owns the system and claims the certificates.

System size is usually the biggest single driver of the amount you finance, so settle that first: what size solar system a Perth home needs.

Should you pay for solar in cash?

If you have the money sitting there and nothing else competing for it, cash is the simplest route. No interest, no repayments and no third party, so your savings start from day one and all of them are yours. You typically pay at commissioning, when the installer invoices on completion and before the meter upgrade. Payback then depends only on what the system cost and what it saves.

Say the system costs $6,500 after STCs and saves $1,500 a year. That pays back in 4.3 years. Over 25 years, $1,500/yr × 25 years, less the $6,500 system cost, comes to about $31,000 before panel degradation and tariff changes.

Is a personal or green loan a good way to finance solar?

It can be, if you don't have the capital upfront and your monthly saving covers most of the repayment. You borrow the system cost from a bank or credit union and repay it over 3–7 years. The common structure is a fixed-rate unsecured loan, but offers can also be variable-rate or secured against an asset, so check which one you're looking at before you line offers up against each other. Some lenders run a dedicated green personal loan for solar and energy-efficiency purchases, so ask whether one is available instead of defaulting to the standard product.

Personal loan rates in Australia in 2026 typically range from 6.5%–12.5% for creditworthy borrowers. Rates, fees and conditions vary by lender and product, so compare green and standard offers side by side. Approval criteria vary too, and a green loan can carry conditions a standard one doesn't. Confirm them before you sign the installation contract, and judge offers on total cost, not the monthly figure.

Here's how it plays out on a $6,500 system at 8% over 5 years. The repayment comes to about $131 a month, which adds roughly $1,370 in interest and takes the total cost to about $7,870. If the system saves $1,500 a year, that's $125 a month against a $131 repayment. So you run slightly behind, close to break-even, until the loan is repaid. After that, the full $1,500 a year is yours. Counting the interest, effective payback from the original cost is about 5.2 years.

A quick test for your own numbers: divide the annual saving by 12 and put it next to the monthly repayment. If the saving is larger, the system is cash-flow positive from the start.

Can you finance solar with a mortgage redraw?

Yes, if you have equity and a redraw or home equity facility. You redraw from your mortgage, or take a home equity loan, at mortgage interest rates (currently 6%–7.5% variable in Australia). That's usually lower than an unsecured personal loan. On a $6,500 redraw at 6.5% repaid over five years, the extra interest is approximately $1,100, so the effective cost is approximately $7,600.

The catch is that a redraw extends your mortgage balance, so compare it against paying cash rather than treating it as free money. The conditions attached to the facility vary by lender, so confirm them before you rely on it. It suits owners with equity who like the repayment flexibility of a mortgage.

What is Synergy's HEEL loan, and does it cover solar?

HEEL (Home Energy Efficiency Loan) is Synergy's loan for eligible energy-efficiency upgrades. It's offered interest-free or low-interest, and you repay it as an extra charge on your electricity bill. As of 2026 it covers eligible upgrades including solar, batteries, heat pump hot water systems and insulation, and repayment is typically added to the bill over 36–60 months. If the loan is genuinely interest-free, the total cost matches paying cash, and repaying through a bill you already receive keeps the admin simple.

The terms have changed over time, so check these with Synergy directly before you rely on it:

• the maximum loan amount, which has varied
• the eligible equipment list, since not every solar brand or battery type qualifies
• whether the loan can cover a battery as well as panels
• whether the current rate is zero, subsidised or variable
• income criteria, because some HEEL variants are means-tested

You apply through Synergy's website or by phone. The application comes before installation, so build the approval time into your timeline.

Is a solar power purchase agreement (PPA) worth considering?

Only in a narrow set of cases. With a PPA, a third-party company installs solar on your roof at no upfront cost, owns the system, and you buy the electricity it generates at a rate the contract sets. It suits households that can't access finance at all, and only where the offer beats your current bill on its own terms. PPAs are far more common in commercial solar than residential in WA, and residential providers in Perth are limited compared with the eastern states.

The appeal is zero upfront cost and a rate that may sit below the grid tariff from day one. Whether it actually does depends on the contract, so read the full tariff schedule, including any escalation, before treating it as a saving.

Then weigh the catches:

• You don't own the system, so the provider claims the STCs, not you.
• Contract terms of 10–25 years can complicate selling the house.
• At the end of the term you may be able to buy the system at residual value, renegotiate, or have it removed.
• The discounted rate can rise over time, so look for rate-escalation clauses.

Whether owning beats a PPA is a totals question, not a rule. Put the loan's cost over its term against the PPA's rate, escalation, maintenance and buyout terms across the whole contract.

What should you compare between solar finance offers?

The total cost over the term, not the monthly figure. For a standalone loan, multiply the repayment by the number of repayments, add the fees, and compare that against the cash price. A cheaper system on a worse rate can still finish ahead of a dearer one on a good rate, or behind it, so this is the number that settles it. A redraw doesn't work that way, because keeping your existing mortgage repayment simply stretches the balance out. Ask the lender for the extra interest the redraw adds, or set a repayment that clears the redrawn amount over a term you choose.

After that, the installed price is usually the largest single input into the total, and typically the one with the most room in it. How to negotiate a solar quote in Perth covers where that room actually is. Put your annual saving divided by 12 next to the monthly repayment, which tells you whether the system pays its own way before the loan ends. Then look at fees, because establishment, monthly account and early-repayment fees can move the total more than a small rate difference does.

Also think about what happens if you sell. A personal loan follows you, and a mortgage redraw is simply part of the loan balance discharged out of settlement. A PPA is the one tied to the property, so check its assignment and buyout terms before you list the house, not after. Last, ask whether the finance ties you to one installer. Finance arranged through the installer can narrow your equipment choice, and a quote you've already financed is harder to walk away from.

Which solar finance option fits your situation?

If you're buying outright and your installer is handling the certificates, the rebate comes off first, and the discounted installed price is the figure you finance. The other routes don't work that way. If you plan to claim the STCs yourself, or you're considering a PPA where the provider claims them, go back to the rebate and PPA sections above.

To see what system suits your home before you pick a route, run your free energy audit report. When you're ready to compare offers, get quotes from Perth installers in the WattMate network.

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Personal loan rates, Synergy HEEL loan terms, eligibility conditions and PPA availability change frequently. Verify current rates, terms and eligibility with your lender and Synergy before making a financing decision. This guide is not financial advice.