Article

When Borrowing For Solar Is A Bad Idea (And Saving Is Safer)

Thinking about solar but not sure if you should borrow or save? Here’s a simple, decision‑grade guide to when financing solar is too risky and waiting is smarter.

Published 1 Sept 2026Updated 1 Sept 20266 min read

Key Takeaway

Australians should avoid borrowing for solar when doing so would push total home and investment loan repayments above about 30–35% of after‑tax income at current rates plus a 3% buffer, or when they lack a 6–12 month cash/offset buffer. In those cases, long 25–30 year solar loan terms and installer‑linked finance can sharply increase risk and total interest. A clear stress test and cashflow check this week can show whether saving for solar is the safer path.

When Borrowing For Solar Is A Bad Idea (And Saving Is Safer)

This topic is covered in full on Tailored Loans Sydney

Thinking about solar but not sure if you should borrow or save? Here’s a simple, decision‑grade guide to when financing solar is too risky and waiting is smarter.

Read the full guide on tailoredloans.sydney

If borrowing for solar would stretch your cashflow, force ultra‑long loan terms, erode your cash buffer, or rely on optimistic bill savings to stay afloat, you’re usually better off waiting and saving instead of financing panels and batteries.

In other words: if total home and investment loan repayments would go above roughly 30–35% of your after‑tax income when modelled at current rates plus a 3% buffer, treat new solar debt as a red light for now.

1. When solar borrowing tips you into mortgage stress

Start with your whole debt picture, not just the solar quote.

For most households, a safe upper guardrail is:

Total home + investment loan repayments under 30–35% of after‑tax income,
Tested at current interest rates + 3% (the same buffer APRA expects banks to use).

If adding a solar loan or home loan top‑up pushes you beyond that, you’re taking on stress in a market where around 28% of mortgage holders are already ‘at risk’ (Roy Morgan, 2026).

Worked example
After‑tax income: $10,000/month.
Current loans (tested at rate +3%): $3,000/month (30%).
Proposed solar top‑up (7–10 year term): $650/month.
New total: $3,650/month (36.5%).

On paper, the bank might still say “yes”. But you’ve moved past the 35% guardrail many advisers use for self‑employed and leveraged households.

Action this week: run your own stress test. If you don’t know how, talk to a broker who automatically stress‑tests at +3% and caps you around 30–35% of take‑home income even if the bank would go higher.

2. When you’re raiding your emergency buffer to make it work

Borrowing for solar is usually a bad idea if it depends on you using up your safety net.

Strong borrowers tend to hold:

6–12 months of essential living costs plus all loan repayments in cash or offset, especially if self‑employed or on one main income.

You should avoid solar borrowing when:

You’d drop below 3 months of true emergency funds to pay for the system or cover higher repayments.
You need to burn your offset just to qualify for the loan.
You’re already carrying credit cards or personal loans that you’re only just keeping on top of.

In that situation, solar becomes a nice‑to‑have upgrade competing with your financial safety.

Instead, park a monthly “solar fund” in a high‑interest saver or offset and revisit solar once your buffer is back at the 6–12 month mark.

3. When the only way it ‘fits’ is a 25–30 year loan

Solar hardware might last 10–20 years. Spreading the cost over 25–30 years just to make the monthly repayment look small is a big red flag. We’ve seen this often with home loan top‑ups: - Panels + battery cost: $25,000. - At 6.5% over 30 years: about $158/month, total interest ~$31,000+. - At 6.5% over 7 years: about $374/month, total interest ~$6,000. Same system, very different interest bill. If the only way your budget works is: - Rolling solar into the main home loan over 25–30 years, and - Relying on…

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Frequently asked questions

Yes, borrowing for solar can be sensible when your total home and investment loan repayments stay under roughly 30–35% of your after-tax income even after adding the solar debt, tested at current interest rates plus a 3% buffer. You also want a 6–12 month cash or offset buffer and a clear plan to repay the solar portion in about 7–10 years, not over the full 25–30 year home loan term.

Using offset savings for solar can work if you still have 6–12 months of living costs and loan repayments left in cash or offset after the spend. If paying for solar would drain your buffer below that level, it’s safer to hold onto the offset balance and build a separate savings plan for solar instead of leaving yourself exposed to rate rises or income shocks.

A bank approval doesn’t automatically mean the loan is safe for you. Lenders work off standard assumptions and don’t factor in all your personal goals, lifestyle choices or risk tolerance. It’s wise to set your own cap, keeping total repayments under about 30–35% of after-tax income at a 3% higher interest rate, even if the bank would lend you more on paper.

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