No successful business would accept weeks of zero income without asking why. Yet many landlords live with void periods between tenancies as if they were simply part of the process.
They are not. Every empty day has a cost, and in London that cost is higher than most owners realise.
What a void period actually costs
Take a flat let at £3,000 a month. That is £36,000 a year, or about £99 a day and £690 a week in lost rent.
And lost rent is only the start. While the property is empty, the costs of owning it carry on:
- mortgage payments;
- service charge and ground rent;
- council tax, which the owner normally pays while no one lives there;
- utilities, including standing charges and anything left on to keep the property heated and dry;
- insurance, where many landlord policies restrict cover once a property has been unoccupied for a set number of days, so a long void can leave you less protected exactly when you are most exposed.
In Kensington and Chelsea, where the average private rent was £3,690 a month in August 2026 according to the ONS, the numbers get bigger. In our experience, a well-priced flat in the borough typically lets within about two weeks, while an overpriced one can sit for six weeks or more. Twenty-five extra empty days at the borough’s average rent is more than £3,000 of rent that never comes back.
Why a higher rent can earn you less
Many owners become fixated on the monthly rent. Experienced investors watch something else: annual revenue.
Consider two options for the same flat:
| Option A | Option B | |
|---|---|---|
| Monthly rent | £3,000 | £3,200 |
| Empty before it lets | 0 weeks | 8 weeks |
| Rent received in year one | £36,000 | £32,492 |
The “cheaper” option earns about £3,500 more in the first year. The higher rent only catches up after roughly another eighteen months, and only if the tenant stays that long and nothing else goes wrong.
In other words, a void wipes out a rent premium far faster than the premium can rebuild it. On a £3,200 flat, each empty week costs around £740 of rent, which is nearly four months of a £200 premium.
Why voids happen
Voids rarely come down to bad luck. The usual causes are:
- Pricing from the wrong starting point. Asking prices on the portals show what landlords want, not what tenants pay. A flat anchored to a figure from a stronger market can sit for weeks.
- Starting the search too late. Marketing that begins when the tenant hands back the keys is marketing that started two months late.
- Slow work between tenancies. Decorating, repairs and cleaning that are only booked once the property is empty add days or weeks.
- Poor presentation. Dark photos, no floor plan and a tired listing lose viewings to better-presented flats nearby.
- Ignoring the season. London’s rental demand rises and falls through the year, and a property that comes to market in a quiet month needs a different plan.
- Waiting for the “perfect” tenant with no income in the meantime.
Seven ways to cut void periods
1. Price to the market from day one
Base the rent on what comparable properties have actually let for recently, not on asking prices. If a well-presented property has had no serious interest in its first week or so, the price is the first thing to look at.
2. Start marketing as soon as notice is served
Since the Renters’ Rights Act took effect on 1 May 2026, tenants can end their tenancy by giving at least two months’ notice. Treat that notice as the start of your marketing window, with viewings arranged in line with the tenancy agreement.
3. Plan the turnaround before the tenant leaves
Book the check-out, cleaners, decorators and any repairs in advance, so the property is ready to show and let within days of becoming empty.
4. Present it properly
Professional photography, a floor plan and a clear, specific description are not extras. They decide whether a tenant books a viewing at all.
5. Keep the good tenants you have
The cheapest void is the one that never happens. Responsive maintenance and fair, well-judged rent reviews keep reliable tenants in place for longer.
6. Make the gap earn
If the right long-term tenant has not been found by the time the property is empty, it does not have to sit idle. Under a hybrid letting strategy, it launches as a serviced apartment for short and medium-term stays, within London’s 90-night rule, and earns while we find the right tenant without pressure.
7. Work with the season, not against it
Know when demand in your area peaks and dips, and plan tenancy end dates, pricing and works around it.
Voids and the Renters’ Rights Act
The new rules make void planning more important, not less:
- Tenancies no longer have fixed terms, so a tenant can leave with two months’ notice at any point, and voids are harder to predict.
- Advertised rents must now be stated, and landlords cannot accept offers above them. Bidding wars can no longer rescue a property priced too low, and an overpriced one simply sits. Pricing it right the first time matters more than ever.
- Choosing the right tenant matters more, because ending a tenancy now needs a legal ground. That puts even more weight on not being rushed into an applicant by a mounting void.
Know what your voids are costing you
If you do not know your average void length, your cost per empty day, and how your achieved rent compares with the market, you are managing on instinct. We offer a free Property Performance Review: no pitch, no obligation. We look at your current setup, achieved rent against market rate, your void periods and your management costs, and tell you honestly where you stand.
Sources: ONS, Private rent and house prices, UK: September 2026 · Gowling WLG, Renters’ Rights Act 2025: 1 May 2026