How to finance solar in Perth: loans, leases and what actually makes sense

Most Perth households don't pay cash for solar — and that's fine. The right financing structure can let you start saving on day one even while you're paying off the system. The wrong one can cost you thousands more than necessary over the loan term.

Here's how each option compares.

Option 1: cash purchase

The baseline. You pay the full installed price upfront, receive the STC rebate as a point-of-sale discount from your installer, and own the system outright from day one.

For a 6.6kW system in Perth after STCs (roughly $1,800 off), the typical out-of-pocket cost is $4,500–7,000 depending on equipment and installer.

Pros:

• No interest cost — you get 100% of the savings from day one
• No ongoing payments — surplus savings go straight to your pocket
• Shortest payback period (typically 3–5 years)

Cons:

• Large upfront outlay, competing with other uses for savings
• Opportunity cost if that cash was otherwise invested

If you have the cash available at reasonable opportunity cost, outright purchase is almost always the best financial outcome over the system's 25-year life.

Option 2: personal loan (unsecured)

Standard personal loans from banks or credit unions at rates ranging from approximately 7–14% p.a. in 2026.

For a $6,000 solar installation:

• 5-year loan at 9% p.a.: ~$124/month, total repayment ~$7,450
• 5-year loan at 12% p.a.: ~$133/month, total repayment ~$8,000
• Interest cost vs cash purchase: $1,450–2,000 extra

The savings offset: A 6.6kW Perth system generating $1,540/year in savings (at current rates) is roughly $128/month. At a 9% loan rate, the monthly repayment and monthly savings are nearly balanced — you're close to cash-flow neutral from day one.

Pros: Simple, widely available, fast approval, outright ownership from day one Cons: Higher interest rate than specialist green loans, interest costs reduce net savings

Option 3: green loan or sustainability loan

Several Australian lenders offer dedicated "green" or "sustainability" loans for solar, batteries, and energy-efficient appliances at reduced rates — typically 5–8% p.a. in 2026. Some credit unions (such as Bank Australia and Teachers Mutual) are known for competitive green loan products.

For the same $6,000 solar installation:

• 5-year loan at 6% p.a.: ~$116/month, total repayment ~$6,950
• Interest cost vs cash purchase: ~$950

Pros: Lower rate than general personal loans, same outright ownership from day one Cons: May require specific lenders or membership (credit union); approval process similar to personal loan

Worth comparing green loan products from your existing bank and specialist lenders before settling on a personal loan.

Option 4: home loan top-up or redraw

If you have an offset account or redraw facility on a home loan with a low interest rate (say, 5.5–6.5% p.a. in 2026), using that facility can be the cheapest financing option after cash.

Adding $6,000 to a 20-year home loan at 6% and repaying at the same rate adds approximately $43/month to repayments. The $128/month solar savings more than covers this — and the effective interest cost is lower than any personal or green loan.

Pros: Often the lowest effective rate for owner-occupiers with an existing low-rate mortgage Cons: Extends the loan term (or requires increased repayments to avoid this); requires a mortgage with redraw/offset access

Speak with your lender about the mechanics — drawing on redraw is often faster and simpler than applying for a new loan.

Option 5: buy now, pay later (BNPL)

Some solar companies offer BNPL arrangements — interest-free periods of 12–24 months, then a higher rate if the balance isn't paid. This can work well if you can clear the balance within the interest-free window.

Watch for:

• The rate after the interest-free period ends (often 19–29% p.a. — extremely expensive if balance remains)
• Establishment fees that reduce the "interest-free" value
• Whether the full STC rebate is being passed through or retained by the BNPL provider

If you can repay within the interest-free period, BNPL can be interest-free financing. If there's any risk you won't, the fallback rate makes it very expensive.

Option 6: solar lease or power purchase agreement (PPA)

Under a solar lease or PPA, a third party owns the panels on your roof and you pay for the electricity they generate — typically at a rate below your grid rate but above zero.

Solar lease: You pay a fixed monthly amount for use of the system (regardless of how much it generates). At end of term, you usually have an option to buy.

PPA: You pay per kWh generated, at a contracted rate. If the system generates less (cloudy day), you pay less.

Pros: No upfront cost, no maintenance responsibility (the system owner handles it)

Cons:

• You don't own the system — no asset at end of loan, no STC rebate benefit
• Complicates selling your home (buyer must assume the lease, or you must buy out the contract)
• Over the full term, total cost is often higher than a green loan would have been
• PPA rates can include annual escalators (1–3%/year is common in contracts)

Solar leases and PPAs are rare in WA compared to eastern states, and not recommended for most Perth owner-occupiers who have the means to finance ownership directly.

Comparing the total cost over 10 years

For a $6,000 solar system with $1,540/year savings (A1 tariff, 6.6kW, Perth):

| Option | Financing cost | Net savings over 10 years | |---|---|---| | Cash purchase | $0 | ~$15,400 | | Green loan (6%, 5yr) | ~$950 | ~$14,450 | | Personal loan (9%, 5yr) | ~$1,450 | ~$13,950 | | Personal loan (12%, 5yr) | ~$2,000 | ~$13,400 | | BNPL (interest-free 24m, then 25%) | $0–3,000+ | Highly variable | | Solar lease | Ongoing payments | Generally worse than ownership |

Cash is best; green loan is a close second; personal loan is workable; lease is usually last resort.

The STC rebate with financed purchases

The STC rebate applies to the installed price regardless of financing method — your installer deducts it before quoting your final price. There's no difference in rebate between cash and financed purchases.

If you're also adding a battery: the WA Battery Scheme rebate (up to $1,300) similarly applies at point of sale regardless of how you're financing the system. Both rebates reduce the amount you need to borrow.

What to do next

1. Get at least three installer quotes (including itemised equipment specs)
2. Check your existing home loan for redraw/offset options — this is often overlooked
3. Compare green loans from credit unions against your main bank's personal loan rate
4. Calculate the break-even: monthly savings vs monthly repayment

Upload your current Synergy bill to BillWise → to see your actual savings projection before committing to a financing structure. Knowing your expected annual savings in dollars makes the loan-vs-cash comparison straightforward.

Loan rates are indicative ranges as of mid-2026 from Australian retail lenders. Actual rates vary by lender, credit history, and loan term. Savings estimates use Synergy A1 rates from 1 July 2026 (33.26c/kWh) and Perth Zone 3 solar conditions. This is general information only — speak with a financial adviser for advice tailored to your circumstances.