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Air Conditioning in a Phnom Penh Apartment: Smells, Leaks and Maintenance

NovAsia · updated July 23, 2026

Prepared by the NovAsia Editorial Team

In Phnom Penh, residents often notice an air conditioner only when it stops cooling or when a wet mark appears beneath the indoor unit. Between those two points, the system may continue to run for months while airflow weakens, the room develops a heavy smell and electricity consumption rises without one obvious cause.

For a tenant, this becomes a dispute about who should call and pay the technician. For an owner, it is a recurring operating cost that is easy to underestimate. The equipment itself may not be fundamentally broken. The result can come from several small factors together: clogged filters, a poorly laid drain, a damp wall, an outdoor unit that cannot reject heat effectively and a habit of setting an unnecessarily low temperature.

In Phnom Penh's hot, humid environment, air conditioning is not a minor appliance. It affects sleep, indoor odour, moisture, finishes, rental satisfaction and how the apartment performs during the rainy season.

Cold air does not prove good condition

During a viewing, the air conditioner is often switched on for a few minutes. Cool air comes from the grille, and the agent or owner concludes that the unit works. That test only proves that the system can start and produce some cooling.

After a week of normal use, different questions matter:

A poorly maintained system can create the appearance of normal operation. Air immediately at the outlet feels cold, but low airflow means the room cools slowly. The compressor runs longer, the electricity meter continues to turn and the resident begins to accept excessive running time as normal.

Daikin's consumer maintenance guidance notes that dirty filters restrict airflow and increase the energy needed for cooling. The manufacturer often recommends frequent filter cleaning, although the appropriate interval in a real Phnom Penh apartment depends on dust, pets, nearby fit-outs and daily operating hours.

A filter is also a useful indicator of management quality. Where it is covered in dense grey dust and produces an odour at start-up, the coil, drain pan and drainage line may also have received limited attention.

Smell and water can have several causes

An odour from an air conditioner does not point to one automatic diagnosis. After a long period without use, dust may be the main cause. Moisture on the heat exchanger and in the drain pan can make biological odours more noticeable. In other cases, the source is not the appliance at all but the wall behind it, a cabinet or an area repeatedly wetted by condensate.

A common sequence is a faint wet line below the indoor unit in the morning. It is wiped away, the equipment continues to run and several days later the paint begins to swell. Possible causes include:

Filter cleaning alone cannot correct those faults.

It is especially important in a tropical climate to distinguish condensate generated by the air conditioner from moisture entering the room through the building. An external-wall leak, balcony waterproofing defect or plumbing issue may first become visible close to the unit and be wrongly attributed to the appliance.

US Environmental Protection Agency guidance on mould consistently places moisture control at the centre of the solution. If the water source remains, an air purifier, fresh filter or cosmetic treatment will not provide a lasting result.

A smell may improve after deep cleaning and return within weeks. That suggests the problem is wider than surface dust. The drain may be backing up, the wall may still be wet or the room may remain persistently humid because ventilation and cooling are inadequate.

Large areas of mould, recurrent leakage or a pronounced odour should not be treated as ordinary housekeeping. They justify investigation of the moisture source and, where appropriate, assessment by an air-conditioning or building specialist.

The rainy season changes the diagnosis

Cambodia has a humid tropical monsoon climate. For an apartment, this means more than a general description of hot weather. A wall that appears dry during one part of the year may become damp during prolonged rain. Drainage that coped in dry conditions may leak. Odours become stronger because surfaces remain wet longer.

During humid periods, an air conditioner has two roles:

  1. reducing air temperature;
  2. removing part of the indoor moisture.

A system used only in short bursts may cool briefly while the room quickly regains heat and humidity. A unit that is too small may run almost continuously without producing stable comfort.

An oversized system is not always ideal either. It can reduce temperature quickly and stop before removing enough moisture, leaving the room cool but clammy. That does not mean every uncomfortable room is the result of incorrect capacity, but capacity and operating pattern belong in the diagnosis.

Observe the room over time:

High humidity does not make every Phnom Penh apartment problematic. It makes weak ventilation, furniture against a damp wall, an unvented bathroom and neglected air conditioning reinforce one another more quickly.

Responsibility should be agreed before a fault

The payment dispute often begins after the first service call. The tenant sees the air conditioner as part of the rented apartment and expects the owner to maintain it. The owner argues that filters became dirty during occupation and normal cleaning belongs to the resident. Either position can sound reasonable when the lease is silent.

There is no single operational rule that allocates every air-conditioning cost in every Phnom Penh lease. Agreements, rental periods and service arrangements differ. In one building, management organises regular servicing. In another, the resident selects a technician and the owner becomes involved only for major faults.

A workable allocation separates several categories:

Everyday care

Periodic professional service

Repair

Pre-existing defect

A tenant should not be made responsible for correcting an old installation defect merely because it becomes visible during the lease. An owner should not be expected to absorb damage that increased because a resident ignored obvious dripping for weeks.

The strongest lease wording is often short:

Clear allocation protects both parties. It encourages early reporting and prevents a small blockage from becoming damaged plaster, furniture and a dissatisfied tenant.

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"Cleaning" can describe very different work

A low-cost service may remove and rinse the filters, wipe the casing and confirm that the unit starts. A deeper service may clean the coil, blower, drain pan and line, inspect the outdoor unit and check operating performance.

Those are not the same product. Compare the scope, not only the price.

A useful quotation identifies:

Surface cleaning can improve smell. It will not solve poor cooling caused by a refrigerant leak, a blocked outdoor coil, fan failure, incorrect capacity or power problem.

The reverse mistake is to assume every weak system needs "more gas". Refrigerant should not disappear regularly from a sound sealed circuit. If the level is genuinely low, the technician should consider leakage. Repeated top-ups without identifying the cause create a temporary improvement and a recurring bill.

Ask what was done rather than accepting "the air conditioner was serviced". A current work record or clear service description is stronger evidence. Test the appliance after the service under normal conditions, not for two minutes.

For an owner, servicing should be part of the asset's lifecycle. Routine cleaning does not remove the eventual need to replace old equipment. A furnished investment apartment needs a reserve for repairs and replacement, particularly where units run for many hours per day.

Why electricity consumption can rise

Air conditioning is often the largest variable electrical load in the apartment. A higher bill therefore appears to prove that the system is defective. In practice, consumption depends on several connected factors:

A dirty filter restricts airflow and can lengthen operation. Similar effects come from a gap under a door, an unshaded glass wall or equipment that is too small for the space.

Selecting an extremely low temperature does not normally make a residential split system produce "extra-cold" air. It tends to keep the system running longer because the target may be unrealistic for the room.

A move can also change consumption without a fault. Remote work adds daytime cooling hours. The bedroom and living room may operate together. The resident may use cooling longer during humid weather.

Do not judge by one invoice. Compare:

A combination of weak airflow, continuous maximum operation, unusual noise, odour, icing and deteriorating cooling justifies diagnosis. One expensive month alone does not.

Inspect each unit before renting

Air conditioning rarely requires rejecting an otherwise good apartment where the condition is clear and responsibilities are agreed. The warning sign is a combination of smell, moisture evidence and reluctance to discuss service history.

Before signing:

  1. Run every unit for at least 15 to 20 minutes.
  2. Check airflow and cooling across the room.
  3. Listen for vibration and rattling.
  4. Smell the air at start-up and after running.
  5. Inspect below the indoor unit and around pipe penetrations.
  6. Look for swollen paint, recent patches or staining.
  7. Confirm when the last substantial service took place.
  8. Ask who pays for routine service, diagnosis, repair and replacement.
  9. Confirm the process for selecting a technician.
  10. Photograph the equipment and surrounding finishes at move-in.

Do not assume the bedroom is covered because the living room is cool. Confirm which rooms have independent units and whether the installed capacity matches their use.

Where one unit smells or cools slowly, a reasonable solution may be professional servicing before move-in followed by a second test. Where fresh paint covers a damp patch and nobody can explain the source, the issue is no longer merely the price of cleaning.

Condition reports protect both sides

Move-in photographs should include:

This prevents old damage from being attributed to the tenant and gives the owner a point of comparison if a new issue develops.

Report water and abnormal symptoms promptly. A useful message states:

The tenant should not dismantle or electrically test the unit without qualification. The owner or manager should not keep requesting photographs while active water damages the property.

When ordinary service is not enough

Use a qualified technician where there is:

Water near electrical components requires particular care. The unit should be isolated safely and inspected rather than repeatedly restarted.

Large mould areas or moisture returning after cosmetic repair may require investigation of the building envelope or plumbing, not only the air conditioner.

A technician should explain the cause, not merely propose a familiar service. Repeated gas charging, drain clearing or board replacement without a diagnosis is a sign that the owner needs a more complete assessment or second opinion.

Air conditioning is part of the apartment's quality

A well-performing system is almost invisible. It cools without odour, dripping or constant attention. That is why it receives less attention during a viewing than the view, furniture or balcony.

In Phnom Penh, the condition of climate-control equipment often reveals how the apartment is managed. Clean systems, dry finishes and a clear response process suggest that ordinary maintenance is taken seriously. Dust-heavy filters and painted-over water marks suggest the opposite, even where the lobby looks expensive.

For the tenant, the practical question is not who cleans a filter under an abstract rule. It is whether the apartment remains comfortable and a fault can be resolved quickly. For the owner, the question is not the price of the next service visit. It is whether delayed maintenance will become damaged finishes, vacancy, compensation and equipment replacement.

This material is for general information and does not replace a technical inspection of the air conditioner, electrical system or building. Recurrent leakage, burning smell, abnormal heating, sparking or significant mould requires professional assessment rather than routine cleaning alone.

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Sources

  1. Daikin Industries — official consumer guidance on air-conditioner filter cleaning and the relationship between restricted airflow and energy use. Checked 23 July 2026.
  2. United States Environmental Protection Agency — *A Brief Guide to Mold, Moisture and Your Home*, updated 18 February 2026. Used for the principle that moisture sources must be corrected.
  3. United States Environmental Protection Agency — current indoor-air-quality materials on biological contaminants, humidity and ventilation. Checked 23 July 2026.
  4. World Bank Climate Change Knowledge Portal — Cambodia climate profile, used for general context on the country's humid tropical monsoon climate.

Frequently asked

Does the tenant have to pay for air-conditioner cleaning?

There is no single rule for every lease. Routine maintenance, repairs and correction of pre-existing defects should be allocated clearly in writing.

Will cleaning remove a mould smell?

Sometimes, where the source is the filter or indoor unit. The smell will return if a leak, damp wall or drainage problem remains.

Why can an air conditioner still cool poorly after cleaning?

The cause may be a refrigerant leak, dirty heat exchanger, fan fault, incorrect capacity, weak installation or a problem with the outdoor unit rather than the filters.

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