Equity and borrowing guide
Using home equity for solar or energy upgrades: what to weigh up.
Home equity can sometimes be used to fund solar, batteries or efficiency upgrades by increasing the home loan or adding a separate loan secured against the property. This can change repayments, the loan term, total interest and how long the home will carry the extra debt.
This guide explains how that could work mechanically, the risks and trade-offs to be aware of, and why borrowing against equity is not automatically the right way to fund energy upgrades.
This information is general and educational. It does not recommend increasing your home loan for any purpose, or assess whether doing so would be suitable in your circumstances.
How solar or energy upgrades is commonly funded
Common approaches include saving in advance, paying from income and cash flow, a green loan or supplier finance, credit cards or lines of credit, borrowing against home equity, or a combination of these.
Each approach has different costs, timeframes and risks, and none is inherently superior in every case. This guide focuses on the implications of using home equity — it does not recommend it.
How home-equity borrowing may work
Borrowing against home equity generally means increasing the amount of debt secured against your property. Mechanically, that could be structured in a few ways:
- Increasing the limit on the existing home loan (a top-up).
- Adding a separate loan split alongside the existing loan.
- Taking out a separate loan secured against the property.
- Refinancing to a larger loan with another lender.
Each of these typically involves a property valuation, an updated application, affordability checks and lender credit assessment. Lenders often cap total secured debt at a certain loan-to-value ratio, and policies differ between lenders. This guide does not show any lender's limits, and no figure on this page is an amount you can or should borrow.
The mortgage-freedom and total-cost impact
Extra debt secured against your home usually means a higher loan balance, possibly an extended loan term, and extra interest over the life of the loan. Even when a home-loan rate is lower than other forms of credit, repaying a smaller amount over many extra years can make the total cost higher, not lower.
Before using equity for solar or energy upgrades, consider:
- How much extra debt you are adding.
- What the repayments would be, and for how long.
- How much extra interest could be paid over the relevant term.
- How the estimated mortgage-free date might change.
- Whether the extra debt is secured against your home.
- What happens if interest rates rise.
- What happens if your income or expenses change.
- Whether you have realistic alternative ways to fund solar or energy upgrades.
As a supporting tool, you can explore how extra borrowing may change a simple loan-to-value estimate: Try the Equity & LVR Calculator. A calculator cannot show whether increasing your home loan is appropriate.
Risks and trade-offs for solar or energy upgrades
- Payback periods depend on your actual usage pattern, not the brochure estimate.
- Government rebates and schemes may reduce how much needs to be borrowed at all — check these first.
- Warranties, installer accreditation and system sizing affect whether the upgrade holds its value.
- Even for value-adding works, the borrowing is still secured against your home and accrues interest until repaid.
With any of these approaches, increasing debt secured against your home can increase the risk of losing the home if the loan cannot be repaid.
Questions to ask before using equity for solar or energy upgrades
- What am I trying to achieve, and is additional debt the only way to achieve it?
- How much extra debt would I be adding, and over what repayment horizon?
- What would the repayments be, and how much extra interest could be paid in total?
- How would my estimated mortgage-free date change?
- Have I genuinely compared the alternatives, including saving first?
- What happens to this plan if interest rates rise?
- What happens if my income falls or my expenses increase?
- How does this sit alongside my other financial goals?
Comparing the alternatives
A brief, neutral comparison — none of these is inherently superior in every case.
Using home equity
May involve a lower interest rate, but the debt is secured against your home and is often repaid over a much longer term — which can mean more total interest.
A green loan or supplier finance
Purpose-built energy finance can carry a shorter term matched to the equipment's payback period.
Saving and paying cash
No interest, no additional debt and no risk to your home — but it requires time and discipline, and may not suit urgent needs.
Related equity and borrowing guides
Putting the numbers into your own mortgage.
Calculators and equity-use guides can help you understand how an idea might work on paper, but they cannot show whether increasing your home loan is appropriate in your circumstances.
A Mortgage Freedom Review may help you see:
- The current estimated payoff path for your home loan.
- How additional borrowing for solar or energy upgrades could change the balance, repayments, term and estimated total interest.
- How staying, requesting repricing or considering refinancing compare under stated assumptions.
- Whether additional borrowing appears compatible with your other mortgage-freedom goals.
This starts an enquiry—not a loan application, approval or recommendation to borrow more.
This guide provides general information about how home-equity borrowing might be structured for solar or energy upgrades. It does not take account of your objectives, financial situation or needs. It is not a recommendation to increase your home loan or to use equity for a particular purpose, and it does not assess borrowing capacity, affordability, product suitability or credit approval.