Should You Refinance Your Rental Before Renewal? The Penalty vs Rate-Savings Math

Rates fell. You still have 22 months left on your rental mortgage at 5.94%. The question every landlord asks at this point is the same: do I break and refinance now, or wait it out? The answer is almost always math you can do on the back of an envelope — and almost always different than what your existing lender will tell you.

The Formula

> Net savings = (Old rate – New rate) × Balance × Years remaining – Penalty – Refi costs

That is the entire calculation. Three inputs you control (balance, rate gap, time), two costs you have to confirm (penalty, refi costs).

On rentals specifically, two things bend the math:

1. Penalties on rentals are usually IRD (Interest Rate Differential), not 3-month interest. Even on variable-rate rentals, some lenders apply a higher penalty than they would on owner-occupied. Check the mortgage commitment, not the renewal letter.
2. Refi costs are higher (~$1,800–$2,500 for appraisal, legal, discharge) because there is always a fresh appraisal and new legal on a rental.

Worked Example 1: Big Win

• Balance: $480,000
• Current rate: 5.94% (5-yr fixed, 22 months remaining)
• New rate available: 4.69%
• Penalty (IRD, confirmed with lender): $9,200
• Refi costs: $2,200

Math:

• Rate gap × balance × years = 1.25% × $480,000 × 1.83 yrs = $10,980 saved over remaining term
• Minus penalty + costs = $11,400
• Net over remaining term: –$420 (a near wash on remaining term alone)

But here is what most calculators miss: the new mortgage is a fresh 5-year term at 4.69%. The savings continue for 3 years past the original maturity date because you locked in a lower rate longer.

• Years 3–5 of new term: 1.25% × $480,000 × 3 yrs = $18,000 additional savings vs renewing at today's expected rate

Total net benefit: roughly $17,500 over 5 years. Easy yes.

Worked Example 2: Easy No

• Balance: $310,000
• Current rate: 5.14% (5-yr fixed, 8 months remaining)
• New rate available: 4.69%
• Penalty (IRD): $4,800
• Refi costs: $2,100

Math:

• Rate gap × balance × years = 0.45% × $310,000 × 0.67 yrs = $935 saved over remaining term
• Penalty + costs: $6,900
• Net over remaining term: –$5,965

What about extending past maturity? The fresh 5-year term locks 4.69% versus an unknown future rate. If you assume rates are flat at 4.69% in 8 months, the future savings = $0. To break even, you need rates to rise to ~5.50% by your maturity date — possible, but not a bet that justifies a $5,965 hole.

Verdict: wait. At 8 months out, you are inside the early renewal window for most lenders anyway — you can lock today's rate without breaking. See Refinancing & Renewing a Rental or Investment Property Mortgage in Canada: The 2026 Playbook for the timing playbook.

The Trap: "Blend and Extend"

Your existing lender will almost always offer a "blend and extend" instead of a break. They blend your old rate with today's rate weighted by remaining term, then extend you back to a fresh 5-year. On paper, no penalty.

What actually happens: the "blended rate" is calculated against the lender's posted rate, not their best available. You end up locked in at 5.20% when the market is offering 4.69%. The "no penalty" is offset by 50 bps of permanent overpayment for 5 years. On $480K, that is $12,000 over the term.

Always quote the blend-and-extend, then quote the break-and-refi at a different lender, then pick the cheaper number. About 70% of the time, breaking wins on rentals because the rental discount your existing lender gave you in the first place was small, so the IRD is small.

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When the Math Always Favors Breaking

Three scenarios where you should not even run the calculator:

1. Variable-rate rentals when the discount has narrowed. 3-month interest penalty on a variable is usually $2,000–$4,000. Almost always recovered in 6–12 months.
2. Rate gap of 1.00%+ with 18+ months remaining. Even with a $10K penalty, the math wins.
3. You are refinancing to pull equity anyway. Penalty becomes a cost of the equity, not a cost of the rate switch. Often the right call.

When the Math Almost Always Favors Waiting

1. Inside 6 months of maturity. Use the early renewal window — no penalty.
2. Rate gap under 50 bps. Penalty + costs almost never recovered.
3. Old rate is already below 4.50%. You have a special. Don't break it.

For more detail on the renewal-switch timing playbook, see Investment Property Renewal: Why Your Bank Is Not Offering the Best Rate (And What to Do About It).