Interest Only Versus Repayment Mortgage Choices

A holiday-let listing can appear to work comfortably until the mortgage is put into the monthly model. That is where the choice between an interest only versus repayment mortgage becomes more than a personal preference. It changes the cash left after costs, the occupancy needed to break even, the capital you build, and the risk you carry if bookings soften.

For a holiday-let buyer, neither structure is automatically better. An interest-only mortgage can protect operating cashflow in seasonal months. A repayment mortgage steadily reduces debt but asks the property to support a much larger monthly commitment. The right decision depends on the deal’s proven earnings, your available cash reserves, your intended holding period and your credible exit plan.

Interest only versus repayment mortgage: the core difference

With an interest-only mortgage, your regular payment covers the interest charged by the lender, but does not reduce the original loan balance. If you borrow £250,000, you still owe £250,000 at the end of the mortgage term unless you have repaid or refinanced it separately. You need a realistic repayment vehicle or exit route for that balance.

With a repayment mortgage, each payment includes interest and a portion of the capital borrowed. In the early years, interest makes up much of the payment. Over time, more of each payment reduces the balance. By the end of the agreed term, assuming every payment is made, the loan should be repaid in full.

The practical difference is immediate. At the same rate and loan size, an interest-only payment is materially lower. That may make a marginal holiday-let deal look investable. But lower monthly payments do not make the property cheaper. They defer the capital repayment question.

Why this decision matters more for holiday lets

Long-term residential landlords can often model income around a relatively stable monthly rent. Holiday-let revenue is less predictable. It may be strong in school holidays and weak between November and February. It can also move quickly with local supply, weather, guest reviews, travel trends and changes to agency ranking or advertising costs.

A mortgage model therefore needs to work beyond an annual gross-revenue headline. The key question is whether net income covers mortgage payments after all realistic operating costs, including management or booking fees, cleaning, utilities, maintenance, insurance, laundry, consumables, local charges, accounting and periods when the property is empty.

A repayment mortgage raises the fixed monthly outgoings that must be met even when occupancy falls. That can be entirely appropriate for a well-capitalised investor buying a property with reliable demand. It is less comfortable where the deal only works under an optimistic occupancy assumption.

Interest only can provide useful breathing room during low season, but it should not be used to disguise weak underlying economics. If the property cannot cover an interest-only payment, ordinary costs and a sensible reserve under a cautious revenue case, it has a more fundamental problem than mortgage structure.

A simple cashflow illustration

Consider a £300,000 holiday let bought with a 25% deposit and a £225,000 mortgage over 25 years. Assume an interest rate of 6% for illustration only.

An interest-only payment would be about £1,125 a month, or £13,500 a year. A capital repayment payment over 25 years would be roughly £1,450 a month, or around £17,400 a year. The precise figures vary by lender, rate, fees and term, but the difference is large enough to affect a deal screen.

That additional £3,900 a year has to come from somewhere. If your average net contribution after direct booking costs is £150 per occupied night, the repayment structure needs roughly 26 more profitable nights each year simply to cover the extra mortgage cost. In reality, the calculation should use your full operating model, because some costs rise as occupancy increases.

This is why break-even occupancy should be visible. Calculate it under both mortgage structures, then test a lower-revenue case. If repayment finance takes the property from a sensible break-even position to one that requires consistently high occupancy, the deal may be carrying more risk than the headline yield suggests.

When interest-only finance may suit a holiday-let investor

Interest only can be a rational choice where the investor is deliberately prioritising cashflow resilience. A property with pronounced seasonality, higher utility costs or a substantial furnishing and maintenance requirement may benefit from lower fixed debt payments, particularly in the first years of ownership.

It can also suit an investor who has a clear and evidenced plan for the capital balance. That may include planned sale proceeds, an investment portfolio, surplus business cashflow or a repayment strategy built outside the property. The point is not that every plan must be complicated. It is that “the property will probably go up in value” is not a repayment strategy.

Interest only may also leave more cash available for the work that protects guest income: replacing tired furnishings, fixing a leaking roof promptly, improving photography or holding a reserve for a quiet period. For short-stay property, these are not cosmetic details. Deferred maintenance can damage reviews and future booking performance.

There are trade-offs. Your debt remains high, refinancing options may depend on loan-to-value and lender criteria, and a fall in property values can make the eventual exit more difficult. The mortgage payment may be lower, but the financial exposure remains.

When a repayment mortgage may be the stronger choice

A repayment mortgage is often a good fit where the property produces a conservative surplus after all costs, not just in a peak-year forecast. It reduces leverage over time, builds equity without relying entirely on price growth and removes the need to find a large capital sum at the end of the term.

For an investor with a long holding period and stable personal finances, that certainty can be valuable. It may also support a more disciplined acquisition decision. If a deal only works on interest only, forcing it through a repayment model can reveal whether the purchase price or borrowing level is simply too high.

The main drawback is reduced flexibility. In a quiet year, the lender still expects the same payment. A repayment structure does not remove the need for cash reserves, particularly for a holiday let where income can be uneven and major repairs rarely arrive at convenient times.

Do not let tax assumptions decide the mortgage

Tax can affect the net return from a holiday let, but it should not be the sole reason to select interest only or repayment. The Furnished Holiday Lettings tax regime was abolished from April 2025, changing the position for many owners. Finance-cost treatment can differ depending on whether you own personally or through a company, alongside your wider circumstances.

Get current advice from a qualified tax professional before relying on any tax saving in your purchase model. More importantly, model the property on a pre-tax cash basis first. The mortgage must be paid from real cash, not from an assumed tax outcome.

Build the mortgage decision into your deal screen

A disciplined comparison uses the same revenue and operating-cost assumptions for both options. Do not make interest only look safer by pairing it with an optimistic booking forecast, then assess repayment against a cautious one.

Start with a realistic annual revenue range rather than one advertised figure. Deduct all operating costs, allowing for replacement items and maintenance rather than treating them as exceptional. Then apply each mortgage payment, include lender fees where relevant, and calculate the annual surplus or shortfall.

Run at least three cases: a cautious case, a base case and a stronger case. For each, identify the break-even occupancy or revenue required. Finally, ask whether you could cover the mortgage and essential costs for several weak months without borrowing more money or relying on personal income you cannot comfortably spare.

Holiday Let Investor’s deal-analysis approach is built around making those assumptions visible. A spreadsheet will not remove risk, but it can show whether the risk is being paid for through a sensible purchase price and adequate cashflow.

Questions to settle before applying

Before choosing a product, establish the loan-to-value you can support without draining your contingency fund, the rate you can still afford at renewal, and whether the lender accepts your proposed holiday-let use. Specialist lending criteria can differ from standard buy-to-let criteria, particularly for Airbnb-style lets, seasonal properties, limited companies and personal-use arrangements.

Also test your exit. If you choose interest only, what specifically clears the balance and what happens if property values are flat when you need to act? If you choose repayment, can the business absorb the higher payment after a poor booking season, a boiler replacement and an increase in insurance premiums?

The best mortgage is not the one that produces the highest projected cashflow on a sales sheet. It is the one your holiday let can support under credible assumptions, while leaving you enough room to respond when the real world does not follow the forecast.