A 120-Room Student Dormitory Had 14 Days to Turn Over Every Room and 31 Still Smelled When the New Tenants Moved In
Last updated: 7 Sep 2026 | 10 Views |
A true story from a 120-room student dormitory near a Thai university
A 120-Room Student Dormitory Had 14 Days to Turn Over Every Room — and 31 Still Smelled When the New Tenants Moved In
When every room has to be ready at the same moment in 14 days, and leftover odour becomes the problem you cannot fix in time
A 120-room student dormitory near a university has only 14 days between old tenants moving out and new ones moving in. Last year 31 rooms still had an odour, and new tenants asked to leave or for a rent reduction. Here is how the dormitory solved it with ozone disinfection and completed every room within the window.
Nongluck, 51, has managed a 120-room student dormitory near a university for nine years. The defining feature of this business is that almost all tenants move in and out together with the academic year, leaving a turnover window of only about 14 days a year.
In those two weeks the team must clean every room, repair what is broken, repaint where needed, and hand every room over on time — already demanding work, made harder because everything must finish simultaneously.
Last year was the worst. Thirty-one of the 120 rooms had new tenants reporting odour within the first week. Seven asked to leave and had their deposits refunded, and another eleven asked for a rent reduction or a different room.
Three kinds of odour the cleaning team could not remove
Nongluck had the team document all 31 problem rooms in detail, and the odours fell into three clear groups — all sharing one characteristic: they were embedded in materials rather than floating in the air.
The first was cigarette smoke, in 14 rooms. Although smoking indoors is prohibited, in practice it cannot be fully controlled. Smoke odour embeds in walls, ceilings, curtains and inside the air conditioner, where wiping down and repainting cannot remove it.
The second was mustiness and mould, in 12 rooms — particularly ground-floor rooms and those facing away from the sun. When a room is shut up for days after the previous tenant leaves, with no ventilation, the odour concentrates further.
The third was cooking and general living odours, in 5 rooms: cooking inside the room, rubbish left behind, and in one case a pet the tenant had kept against the rules, leaving odour embedded in the flooring and in the corners of the room.
Why turnover is the hardest time to solve it
Nongluck explains the problem is not that the cleaning team works badly. It is the constraint of time and the fact that all 120 rooms must be handled simultaneously.
The method the dormitory had always used was opening rooms to ventilate for several days. It genuinely works, but takes at least five to seven days per room — and within a 14-day window that also contains all the other work, there is simply not enough time for every room.
The other method used was repainting, which helps to a degree with smoke odour on walls but does nothing about odour in the ceiling, inside the air conditioner, or in corners paint cannot reach. The smell returns within two to three weeks.
And the factor that makes everything harder is that new tenants arrive almost all at once, so problems all surface at once too. The team cannot work through them room by room the way a building with year-round turnover could.
What it cost, and what cost more than money
The seven rooms that were vacated mean seven rooms empty for the whole academic year, because students look for accommodation at the start of term and virtually nobody looks afterwards — roughly 588,000 baht of lost income.
The eleven rooms asking for rent reductions or room changes reduced income and complicated allocation, because moving a tenant requires a better room to be free — and during a full period there rarely is one.
But the most expensive cost, Nongluck says, is reputation among students and parents, because dormitory choice runs almost entirely on word of mouth between year groups, and parents typically call each other before deciding.
She saw the effect clearly the following year: advance bookings were significantly down on the year before, despite no price increase and the same location within walking distance of the university.
What the dormitory changed, and the following year's turnover
Nongluck consulted the World Health Disinfection team about two months before the next turnover. They surveyed the building and proposed a plan that showed her the problem was solvable within the window she had.
The plan divided the rooms into three groups by severity. Group one was rooms with a history of smoke or strong odour, treated with ozone first, immediately after the previous tenant left. Group two was ground-floor and shaded rooms at risk of mustiness. Group three was everything else.
The sequence the team set was to clean and repair as normal first, then apply ozone as the final step before handover, treating several rooms in the same zone simultaneously to stay on schedule, and ventilating for the specified period before tenants moved in.
The result at the following turnover: from 31 problem rooms down to just 2 reporting any odour, and not a single room vacated. What surprised Nongluck most was that the team finished inside the 14-day window without postponing a single handover.
The real damage
Rooms empty for a whole academic year after missing the start of term
Students look for accommodation only at the start of term, and virtually nobody looks afterwards. So seven vacated rooms stayed empty all year — roughly 588,000 baht of lost income that cannot be recovered within that year at all.
Reputation travelling by word of mouth between year groups
Dormitory choice runs almost entirely on word of mouth between senior and junior students, and parents typically call each other before deciding. An odour problem therefore travels quickly and visibly reduces advance bookings the following year.
The health of tenants who spend all day in their rooms
Students spend far more time in their rooms than people assume, studying and sleeping. Smoke odour embedded in the walls and mould in shaded rooms genuinely affect health, especially for students with allergies or asthma.
The strain on a team working to a very tight window
The team must clean, repair, repaint and hand over 120 rooms within 14 days. When odour problems cannot be solved by the usual method in time, the team is under pressure and quality elsewhere suffers, spreading the problem further.
Why the usual fixes fail
Opening rooms to ventilate for several days
It genuinely works, but takes at least five to seven days per room. Within a 14-day window containing all the other work, there is not enough time for every room — and in the rainy season leaving rooms open lets more humidity in.
Repainting the walls
Helpful to a degree with smoke odour on walls, but it does nothing about odour in the ceiling, inside the air conditioner, in the corners or in the flooring — so the smell returns two to three weeks after the new tenant moves in, which is the hardest moment to deal with it.
Air freshener and deodorising products
These mask for hours or days, and when the original odour returns the tenant feels something was concealed, which produces greater dissatisfaction. For tenants with allergies, the fragrance itself can make symptoms worse.
Cleaning the air conditioner alone
Necessary and worth doing in every room, but insufficient, because smoke and musty odour are not only in the air conditioner. They are embedded in walls, ceilings, curtains and flooring, so servicing the unit addresses only part of the problem.
Replacing all the curtains and soft materials
Genuinely helpful but very expensive multiplied across the rooms, and it still leaves the odour in walls and ceilings, which cannot be replaced. Many dormitories find that new curtains absorb the room's odour again within weeks.
You need a method that is fast and reaches every material in the room at once
Traced to the root, the dormitory's constraint was never knowledge of what to do. It was time: clearing odour within a 14-day window alongside all the other work, across 120 rooms simultaneously.
What is needed is therefore a method that reaches every material in the room in a single operation — walls, ceiling, curtains, flooring, inside the air conditioner, inside the wardrobe and the bathroom — where wiping and painting reach only surfaces a hand can touch.
Ozone is a gas, so it fills the room's volume and penetrates everywhere air reaches at the same time: into air conditioning ducts, behind cabinets, under the bed and into the fabric of the curtains. That capability matches this job's constraint precisely.
And because ozone reverts to oxygen once the process ends, it leaves no residue in a room a student will live in — something parents care about a great deal when they ask.
10 reasons ozone disinfection service solves it
1. The gas fills the room and reaches every material at once
Odour in a room is never in one place. It is embedded in walls, ceiling, curtains, flooring, air conditioning ducts, wardrobes and the bathroom. Being a gas, ozone reaches all of them simultaneously — unlike wiping and painting, which reach only surfaces a hand can touch.
2. Short enough per room to complete 120 rooms in 14 days
This is the decisive factor for a dormitory. Ventilating takes five to seven days per room. Ozone treatment takes far less time per room and several rooms in the same zone can be treated together, so all 120 finish inside the available window.
3. Handles smoke, mustiness and living odours together
Dormitories face several odour types at once with different causes. Ozone acts on the organic compounds producing them across a range of types, so a single process addresses them all rather than needing a different method for each.
4. No residue in a room a student will live in
Ozone reverts to oxygen once the process ends, so nothing remains in the room — something parents care about greatly when they ask, and quite unlike deodorising products that leave both fragrance and chemical behind.
5. It also addresses mould in shaded rooms
Ground-floor rooms and those facing away from the sun tend to have recurring mould problems every year. Ozone treatment addresses both the odour and the mould causing it, reducing how quickly the problem returns in those rooms.
6. It reaches inside the air conditioner and the ducting
Part of the smoke and musty odour sits inside the air conditioner and its ducting, which routine servicing reaches only partially. Gas treatment reaches it far more thoroughly, and is best done after the unit has been serviced.
7. It can be planned by zone, so the schedule is genuinely controllable
The team can plan treatment by zone, several rooms at a time, so the dormitory can commit to handover dates and tell incoming tenants in advance — something room-by-room ventilation can never support.
8. A professional team assesses and prioritises rooms by severity
Not every room needs the same time. Having an experienced team assess and group rooms by severity makes the best use of time and resources and is what allows the work to finish inside a very tight window.
9. A clear, auditable safety procedure
Ozone must be applied in unoccupied rooms with ventilation for a defined period before entry. The World Health Disinfection team follows the procedure every time — securing the room, posting notices, and ventilating before handing it back.
10. It becomes a selling point with tenants and parents
A dormitory that can state every room is disinfected and deodorised before handover has a clear differentiator in a market that otherwise competes on price and location — and it is exactly what parents, who pay the bills, care about.
Before the ozone service
- 31 of 120 rooms with odour reported in the first week
- 7 rooms vacated with deposits refunded
- 11 rooms asking for a rent reduction or a room change
- Roughly 588,000 baht a year lost to vacant rooms
- Advance bookings significantly down the following year
- The old method, ventilation, taking five to seven days per room
After the ozone service
- Only 2 rooms reporting any odour
- Not a single room vacated
- All 120 rooms handed over inside the 14-day window
- Ground-floor rooms with recurring mould clearly improved
- Used as a selling point with parents: every room treated before handover
- Advance bookings the following year higher than before
The service in 3 steps
1. Survey and group the rooms by severity before turnover begins
The team surveys the building in advance and uses each room's complaint history to divide them into three groups: rooms with a history of strong odour, rooms at risk of mustiness and mould, and the rest — then sequences the work so the worst rooms are handled first.
2. Complete cleaning and repairs first, then apply ozone as the final step
Clean, repair, service the air conditioners and repaint first. Then apply ozone as the last step before handover, so all remaining odour is dealt with in one operation with no other work left to interfere with the result.
3. Treat by zone and ventilate for the specified period before handover
Plan treatment several rooms at a time within one zone to stay on schedule, secure the rooms and post notices during the process with nobody present, then ventilate for the specified period before handing the room to the new tenant.
From a real client
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Where odour hides in a room, beyond the reach of ordinary cleaning
The ceiling holds more cigarette odour than anywhere else and is almost never treated, because smoke rises and accumulates there throughout the tenancy. Repainting the walls therefore addresses only part of it, and odour from the ceiling gradually returns into the room after the new tenant moves in.
Inside the air conditioner and its ducting is the second. Odour is drawn into the coil and ducting continuously during use. Routine servicing reaches some of it but not all, and every time the unit runs, the odour is blown back into the room.
Curtains and porous materials are the third: curtains, chair upholstery, mattresses and doormats, which hold odour inside the material. Washing helps but not completely — and new materials will absorb the room's odour again if the room itself has not been treated.
The last is the corners a hand cannot reach: behind built-in wardrobes, under the bed, inside storage voids, and along the joint between floor and wall — where both odour and mould accumulate unseen, and why a room that looks clean can still smell.
Why treatment should be the last step, not the first
Dormitory managers often ask whether to treat before or after cleaning and painting. The answer is that it should be the final step before handover, for three straightforward reasons.
First, cleaning, repairs and painting all generate new odours and dust in the room. Treating first and then doing that work erases most of the benefit.
Second, repainting seals some odour into the wall. Treating after the paint has dried therefore addresses all remaining odour with the room in the condition it will actually be handed over in — the same condition the tenant will live in.
Third, clarity at handover. When treatment is the final step, the team can walk the room after ventilation and confirm immediately that it is ready — which makes the whole handover process systematic and auditable.
Frequently asked questions
How long does one room take?
It depends on room size and severity, but it is dramatically shorter than ventilating for several days, and multiple rooms in one zone can be treated together. The team will assess the site and give you a schedule.
Can people be present in the room or on the same floor?
There must be nobody and no animals in the room being treated. For adjacent areas the team assesses and sets appropriate measures, securing the room, posting notices, and ventilating for the specified period before re-entry.
Is there any smell or residue afterwards?
No. Ozone reverts to oxygen once the process ends. After ventilating for the specified period, the room has no residue and none of the product smell that deodorising sprays leave behind.
Should treatment come before or after painting and cleaning?
After. Complete the cleaning, repairs, air conditioner servicing and painting first, because those generate new odour and dust. Treating last addresses all remaining odour with the room in genuine handover condition.
Can it really deal with smoke odour embedded in the walls?
To a degree clearly different from other methods, because as a gas it reaches the ceiling, the air conditioning ducts, the corners and the curtains — the places holding most of the smoke odour, which repainting never reaches. Severe rooms may need more than one cycle.
How many rooms make it worthwhile?
It is worthwhile even at small scale, because one room left empty for a whole academic year is worth more than treating many rooms. For dormitories where tenants move in and out together with the academic year, the case is stronger still, because all the risk is concentrated in one window.
Does it work for apartments and monthly rentals too?
Yes. The same principle applies to apartments, monthly rentals, rental condominiums and holiday lets, all of which have a turnover window in which rooms must be made ready within limited time.
How is pricing assessed?
On the number of rooms, room size, severity and the timeframe required. The World Health Disinfection team surveys the site and quotes with a working schedule before starting, so the dormitory can commit to handover dates with confidence.
We knew what to do — we just did not have the time
Nongluck's sentence captures the dormitory business precisely: most operators know what needs doing. The real constraint is time, and a method that works but takes too long is, in practice, a method that cannot be used.
Once you frame the problem as one of time rather than knowledge, the solution changes: you need something delivering the same result or better in far less time, and able to handle many rooms at once.
And for a business whose entire year's income is decided in a two-week window, investing to have every room ready on time is not an expense. It is protecting a whole academic year of revenue.
Talk to the World Health Disinfection team about an ozone treatment plan for your dormitory or apartment building, with a schedule that fits your turnover window.
See the ozone disinfection service and pricing — click here
Call 065-556-6294 or add LINE @whd268
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