If you run a UK HMO, you know the spreadsheet line that quietly destroys the year. Vacant rooms. A 5-bed HMO yielding £3,000/month at full occupancy drops to £2,400 the day one room sits empty — an 18% gross yield drop that compounds across the months while you re-list, view, reference, and finally move someone in. Each empty-room week costs roughly £140–£200 of lost rent on a UK regional HMO; £180–£260 on a London HMO. Three weeks of vacancy on one room is typically enough to wipe out the property's net profit for that month.
Most HMO landlords absorb it. A growing minority list the empty room on Packhood as storage for the gap weeks. Not a person — boxes. Identity-checked renter, fixed monthly fee, 4-week minimum commitment, no AST created, no impact on the existing housemates. The room earns £100-£200/mo for the in-between period instead of £0, and the income is fully reversible the day the next sharer moves in.
Below: the actual maths on a 5-bed HMO, why this is genuinely fine alongside an HMO licence (it isn't subletting, it isn't a tenancy), the housemate-consent angle, and the 21-day operational pattern most HMO landlords settle on.
Vacancy economics on a typical UK HMO
Take a 5-bed HMO in a regional UK city — Sheffield, Leeds, Nottingham, Newcastle. Rooms let at £600/month each, all bills included. Fully occupied: £3,000/mo gross. Standard expenses (mortgage interest, bills, council tax, agent, maintenance, contingency): roughly £2,200/mo on a leveraged HMO. Net at full occupancy: ~£800/mo.
One vacant room reduces gross to £2,400/mo, but expenses don't move (bills are absorbed centrally on most HMOs). Net falls to £200/mo. Net profit drops 75% on a single empty room.
Average UK HMO room vacancy in 2026 runs 14-21 days between sharers. So even a "well-run" HMO loses 12-18 days of rent per room per turnover, with most rooms turning over 1-2 times a year. On a 5-bed property that's ~50-150 days of vacant-room-equivalent annually. £1,000-£3,000 of lost rent per year on a £36k gross HMO.
Storage hosting between sharers can recover £75-£200 of that per turnover. On a 5-bed property with 1.5 turnovers per room per year, that's £560-£1,500/yr of recovered income across the portfolio.
Why this isn't subletting and isn't a tenancy
Two questions every HMO landlord asks before they list. The honest answers:
"Will my HMO licence still be valid?" Almost certainly yes. HMO licensing under the Housing Act 2004 covers properties where 3+ unrelated people share facilities. Storage of boxes by a non-resident isn't "occupation" in the licensing sense — the renter doesn't sleep, eat, or live in the room. The room is being used for storage, not as living accommodation. Some councils may want to be informed; very few will object. Always check with your specific council if you have a Mandatory or Selective HMO licence — but the answer is generally fine.
"Won't this break the AST structure with the other housemates?" No. Each housemate has an individual room AST (or is on a joint AST in some setups). The empty-room storage booking is a separate licence agreement covering only that one room — it doesn't touch the other tenancies. The kitchen, bathroom, and common rooms aren't part of the storage booking. The renter has no right to enter common areas.
"What about the existing housemates' contracts?" Most HMO ASTs have a "quiet enjoyment" clause and possibly an explicit "no commercial use" clause. Storage of boxes by someone who isn't living there is unlikely to violate quiet enjoyment (the renter visits ~1.7 times in a 4-month average booking, less in the 1-2 month bridge use case). The "no commercial use" clause typically applies to the housemates running businesses from the property — not to the landlord using a vacant room. Get explicit consent from the existing housemates anyway. They're often happy because storage rentals don't bring noise, smells, or shared-bathroom queues.
The housemate consent script
Existing housemates need to be on board. The right way to ask is in writing, with the framing that protects their interests rather than asking for a favour.
Suggested email: "Hi all — Sarah's room will be empty from the 14th. Rather than chase a new housemate immediately, I'm planning to list it as box-only storage on Packhood for 4-6 weeks while I find the right next housemate. The renter would be checked via Stripe Identity, would visit max 2-3 times across the booking, and wouldn't have access to the kitchen, bathroom or living room. I won't take a discount on your rent for this — your bills allowance stays the same. Any objections?"
This wording works for three reasons: (1) it explicitly carves out the common areas, removing the housemates' main worry; (2) it acknowledges their existing rent isn't changing; (3) it gives them a vote, not just notice — most housemates feel respected by being asked.
In our data, ~85% of UK HMO housemates say yes to this email within 48 hours. The 15% who push back usually want a small reduction in their share of bills (the storage renter does count as occupants for utility-load purposes, however lightly). A £15-20/mo reduction across the housemates often closes the deal.
The 21-day operational pattern
Most HMO landlords settle on a clean 21-day cycle:
Day 0: Sarah moves out. Photograph the room, list it on Packhood at 5% below the local storage market rate. Apply a 1-month minimum commitment.
Day 3-7: Storage renter applies. Identity-verify, book, agree move-in.
Day 7-9: Renter moves boxes in. Smart-lock or keysafe gives them access to the room only. Common areas remain locked from them.
Days 7-30: Run the parallel housemate search (SpareRoom, your usual channels). The room is "earning" rather than "empty."
Day 25-35: New housemate found, signs AST starting Day 45. Notify storage renter that the booking ends Day 38.
Day 38: Storage renter collects boxes. Room cleaned.
Day 45: New housemate moves in.
Net: 3-4 weeks of storage income (£75-£200) recovered on what would otherwise have been a pure-loss vacant-room window. Across a 5-bed HMO with 8 turnovers a year, that's ~£600-£1,600/yr extra net.
When NOT to do this
Storage hosting on an HMO room isn't always the right call. Three situations to skip:
(1) Your HMO licence has explicit conditions about non-resident occupants. Some Mandatory HMO conditions in tighter-regulation councils (Liverpool's Selective Licensing area, parts of Newham, parts of central Manchester) include language about non-resident use. Read your specific licence; if in doubt, call the licensing officer.
(2) Your existing housemates are objecting. If they say no, take it as a no. Storage income on one room isn't worth a fractured relationship with three paying tenants.
(3) Your turnover gap is short. If you've already found the next housemate and they're moving in within 10 days, the operational overhead of listing storage for a one-week gap usually isn't worth it. The break-even is about 21 days of vacancy — under that, just absorb.
How to start
List the room as storage. Twenty minutes — five photos with your phone (one wide of the empty room with the light on, two corners, the room door, the entry route), three sentences of description ("Single room in 5-bed HMO in [postcode], 11m² floor space, 2.4m ceiling, no kitchen/bathroom access included, available [date] for 4-6 weeks"), price 5% below the local Packhood storage median, Stripe Identity verification.
Most HMO listings designed this way book in 3-7 days. The renter pool is healthy — flat-dwellers, students between terms, anyone who needs short-term storage and is happy with a single-room footprint.
The take
HMO landlords are running a tight operation where every pound of vacancy compounds against the net yield. Storage hosting on the gap weeks won't fix the underlying turnover problem (only good housemate selection and tenant retention does that), but it makes each turnover financially less brutal.
On a 5-bed HMO with 1.5 turnovers/room/year, you're looking at £600-£1,600/yr of recovered income — not a fortune, but the kind of money that pays for the boiler service, the gas safety check, or the unexpected electrician callout. The kind of money landlords usually have to find from somewhere.
List the empty room. Twenty minutes. Closed-loop with the next AST. Recoverable income on space the property's already paid for.