Refinancing An Investment Property Or Your Home: How The Rules Differ

Most people assume refinancing an investment property is just refinancing your home with a slightly higher rate. That assumption quietly destroys more tax deductions, buffers and borrowing power than almost anything else I see. Refinancing an investment is a different game: the bank’s risk lens changes, the tax rules bite harder, and the structure matters more than the headline rate.

Put simply: refinancing your home is usually about cashflow and rate. Refinancing an investment property is about strategy, structure and exit options. If you treat them the same, you’re handing control to the bank and the ATO.

Here’s what I tell my clients when they ask whether to refinance the investment, the home – or both – this year.

Home and investment loans should be structured differently when you refinance.

The 60‑second answer: home vs investment refinance

Refinancing your home loan is mainly about: lowering a non‑deductible debt, improving cashflow, and getting flexible features (offset, splits, redraw) without taking stupid risks.

Refinancing an investment loan is about: aligning your debt with post‑2027 tax rules, keeping interest deductible, protecting buffers and preserving your ability to sell or reshuffle properties later.

Key differences in one view:

• Rates & pricing: investment loans usually cost ~0.30–0.80% p.a. more than comparable owner‑occupier loans (illustrative only).
• Assessment: lenders apply APRA’s 3% serviceability buffer to both, but often shade rental income and are tougher on multi‑property investors.
• Tax: home loan interest is generally non‑deductible; investment interest is usually deductible if loan purpose and records are clean.
• Strategy: you normally want your home debt falling fastest and your investment debt structured cleanly for tax and flexibility.

If you remember nothing else: don’t chase the lowest rate at the cost of messy purposes and cross‑collateralisation.

How banks see your home vs your investment

1. Pricing and risk appetite

With owner‑occupier loans, banks care most about household mortgage stress. Roy Morgan’s July 2026 work shows around 32.5% of owner‑occupier borrowers are now “At Risk”, with 22% “Extremely At Risk”, as the RBA cash rate sits around 4.35%. That’s the political and regulatory hot zone.

Investment lending, by contrast, is where banks quietly ration risk. Expect:

• Higher rates on like‑for‑like products, especially if interest‑only.
• Tighter policy once you hold multiple properties or high LVRs.
• More variation across lenders – some love investors, others quietly price them away.

This is why two borrowers with identical incomes can get very different answers depending on whether the refinance is for a home, an investment, or both.

2. Serviceability – same buffer, different inputs

APRA’s guidance means both home and investment loans are tested with a 3% serviceability buffer above the actual rate. But the inputs differ:

• Home loan refinance: lenders focus on your wages, other debts, kids, and expenses benchmarked against HEM.
• Investment refinance: they also factor in rent (often shaded to 70–90%), existing investment debts, and sometimes higher assumed expenses.

A simple example.

• Existing investment loan: $600,000 at 6.5% P&I over 25 years → repayments ≈ $4,046/month.
• Refinance offer: 5.9% P&I over 25 years → ≈ $3,815/month.
• That’s ~$231/month saving.

Serviceability test: the bank might assess at 8.9% (5.9% + 3% buffer), not 5.9%, and shade rent to 80%. On the same income, you may be able to refinance your home but not the investment, even though both would save cashflow.

This is why I often tell clients: “If serviceability is tight, prioritise getting the home loan right, then clean up the investments.”

For a systematic way to stay ahead of this, see the home loan review rhythm I’ve set out in /insights/how-often-review-and-reprice-your-home-loan.