Personal loans vs BNPL vs vendor finance for solar: real costs

Thinking about using a personal loan, buy now pay later (BNPL) or installer “interest‑free” deal to get solar on your roof?

In Australia, personal loans are usually the safest of these three, BNPL is the riskiest for your future borrowing power, and vendor finance often looks cheap but hides high effective interest in the system price and platform fees. The right choice depends on your cashflow, home loan plans and how disciplined you are with debt.

Fast answer: If you expect to refinance, buy another property or borrow for business in the next 2–3 years, avoid BNPL and be very cautious with vendor finance. A transparent, fixed‑term personal loan (or a properly structured home‑loan option) is usually cleaner and easier to compare.

Different ways to fund solar come with very different costs and risks.

1. The three main ways to finance solar without touching your home loan

1.1 Personal loans for solar

A personal loan is a fixed‑term loan (usually 3–7 years) with a set interest rate and repayments. It’s often unsecured, sometimes secured against the solar system or a vehicle.

Pros

• Clear term and repayment schedule.
• Easy to compare between banks and non‑bank lenders.
• Keeps solar debt separate from your home loan.

Cons

• Higher interest rates than home loans (often 9–15% p.a., indicative only).
• Fees can vary and add to the real rate.
• Lower maximum amounts than home‑loan top‑ups.

A short, fixed term that roughly matches the system’s useful life (say 5–10 years) is a big plus; it stops you dragging solar debt out for 25–30 years. This aligns with the principles in structuring solar borrowing.

1.2 BNPL for solar panels and batteries

BNPL platforms now fund some solar installs in instalments (e.g. 12–60 months) with “zero interest” but fixed fees.

Pros

• Fast approvals, minimal paperwork.
• Small, fixed instalments can feel manageable.
• Often promoted as “no interest” or “no credit check” (but there is nearly always an internal assessment).

Cons

• Fees can mimic high interest when you annualise the cost.
• Late fees and missed payments can escalate quickly.
• All facilities typically show on your credit report and reduce your borrowing power.

Even if repayments are only $40–$80 a week, lenders must factor them into serviceability under APRA’s 3% buffer, which can materially reduce how much you can borrow for a home or business loan.

1.3 Vendor or installer‑arranged solar finance

Vendor finance is where the solar company arranges a finance facility – often branded, sometimes via BNPL or a specialist platform.

Pros

• One “package”: quote, install, finance handled together.
• Teaser offers (e.g. 24 months interest‑free) can look attractive.
• May suit households who cannot access mainstream bank credit.

Cons

• The real cost of credit is often hidden in higher system prices and platform fees.¹
• Teaser rates commonly revert to high interest after the promo period.
• Contracts can be complex and hard to exit early.

Before signing anything, read Spotting Dangerous Solar Finance Red Flags Before You Sign. It walks through teaser structures and contract clauses you must understand.