Solar finance options in Perth: upfront, solar loan, or lease?

A 6.6kW solar system in Perth costs approximately $4,000–$6,500 installed after STCs. How you pay for it affects your savings, your risk, and your flexibility over the 10–25 year system life. Here's a comparison of the main options.

Option 1: pay upfront

How it works: You pay the full installed cost from savings or by redrawing on a mortgage offset. You own the system immediately, with no ongoing finance obligations.

Example (6.6kW system, $5,500 installed):

• Upfront cost: $5,500
• Year 1 electricity bill savings: approximately $1,200–$1,800 (depending on self-consumption and tariff)
• Payback period: approximately 3–5 years
• Year 10 net position: $6,000–$12,500 ahead (savings less upfront cost)
• System warranty: 25-year product warranty on panels; 10-year inverter warranty; 5-year workmanship

Best for:

• Households with savings earning low interest (savings rate < payback savings rate)
• Those wanting maximum long-term savings with no ongoing obligations
• Properties owned for the long term

Risk: Full upfront exposure if the system underperforms or has warranty issues in early years.

Option 2: solar loan (most common)

How it works: A lender (bank or specialist solar finance provider) lends you the full system cost. You repay over 3–7 years. You own the system immediately and take the savings immediately.

Example (6.6kW system, $5,500, 5-year loan at 7.5% p.a.):

• Monthly repayments: approximately $111/month ($1,332/year)
• Annual electricity savings (Year 1): approximately $1,400
• Net Year 1 cash flow: +$68/month (savings exceed repayments)
• Total interest paid over 5 years: approximately $830
• Year 5 net position: paid off, now banking $1,400+/year in pure savings
• Total cost of solar (including interest): approximately $6,330

Interest rate context: Solar loan rates in 2026 range from approximately 5.5%–12.9% depending on lender, loan amount, and credit profile. The lower rates (5.5%–7%) are typically from green finance products or banks offering solar-specific loans. Rates above 9% make the loan economics significantly worse — check the comparison rate, not just the headline rate.

Using mortgage offset or redraw: If you have a home loan with an offset account and redraw facility, using those funds to pay for solar "upfront" and then repaying gradually is equivalent to a solar loan at your mortgage interest rate — which is typically lower than personal loan rates. This is often the cheapest finance option for owner-occupiers with home loans.

Best for:

• Households without sufficient savings to pay upfront
• Those wanting immediate savings from Day 1 without a large lump sum
• Positive or neutral cash-flow scenarios (monthly savings ≥ monthly repayment)

Risk: If the system underperforms significantly (e.g. poor weather run, system fault), you continue paying the loan while savings are lower than projected.

Option 3: power purchase agreement (PPA)

How it works: A third party (PPA provider) owns, installs, and maintains solar panels on your roof. You buy the solar electricity they generate at a contracted rate — typically 10–20c/kWh — rather than grid electricity at 33.26c/kWh. You pay the PPA rate for what you use; surplus generation may export at DEBS rates.

Example (6.6kW system, PPA rate 15c/kWh):

• For each kWh you self-consume: you pay 15c (vs 33.26c grid) — saving 18.26c/kWh
• Self-consumption of 15kWh/day × 18.26c × 365 = approximately $1,000/year saving
• The PPA provider takes the DEBS export revenue (or you get it, depending on contract terms — read carefully)
• Typical PPA term: 10–25 years

Key PPA risks:

• You don't own the system — if you sell the property, the PPA must transfer to the new buyer, which can complicate sales. Some buyers decline to take on a PPA obligation.
• PPA contracts typically include annual price escalators (e.g. 2%/year) — your PPA rate may rise over the contract term. If grid electricity prices fall (or if the tariff significantly changes), the PPA saving shrinks.
• The PPA provider handles maintenance and warranty — this is positive (no maintenance risk), but you are dependent on the provider's business continuity over a 10–25 year term.

PPAs in Perth: PPAs are less common in Perth for residential than in some other Australian markets. Check whether any Perth-active PPA providers operate in your area before committing.

Best for:

• Households with no upfront capacity and poor credit for a loan
• Those who want no maintenance responsibility

Risk: Lower long-term financial return than ownership; contract complexity at property sale.

Option 4: government incentive programs

WA Battery Scheme: The $130/kWh (max $1,300) rebate reduces the upfront cost of adding a battery. This is a direct rebate, not a loan — reduces your upfront payment or the loan amount. Eligibility: Synergy customer, min 5kW solar, battery on Synergy Sustainable Storage List.

STCs (Small-scale Technology Certificates): Automatically applied by your installer as a point-of-sale discount (reducing the quoted price). You don't need to do anything separately — it's already in your quote. A 6.6kW Perth system generates approximately 90 STCs, worth approximately $3,700–$4,500 at 2026 STC prices (varies with market).

No WA government solar loan scheme: Unlike some other Australian states, WA does not currently offer a government-backed concessional solar loan program. The WA Battery Scheme is the primary government incentive.

Comparison summary

| Option | Upfront cost | Own the system? | Long-term saving | Best scenario | |---|---|---|---|---| | Upfront payment | $4,000–$6,500 | Yes, Day 1 | Highest (no interest) | Savings available | | Solar loan | $0 upfront | Yes, Day 1 | Good (minus interest) | Positive cash flow loan | | Mortgage redraw | $0 upfront | Yes, Day 1 | Best (mortgage rate) | Owner with home loan + offset | | PPA | $0 upfront | No | Moderate | No upfront, no loan |

Checking your payback before committing

Your payback period depends on:

• Self-consumption ratio (how much you use vs export)
• Tariff (A1 vs Midday Saver changes the economics significantly)
• Actual system cost
• Finance cost (interest rate, term)

Upload your Synergy bill to BillWise to model your actual expected savings before signing a contract.

Never let a solar salesperson tell you there's a "deadline on rebates" that forces you to decide today. STCs are a permanent government program — the only thing that changes annually is the STC deeming period (one fewer year of deeming each January), which reduces the rebate gradually over time, not suddenly.