A meeting room that feels stuffy by mid-morning, recurring headaches among office staff, or complaints that ease after people leave work can point to a building issue rather than an individual health problem. Sick building syndrome (SBS) is a term used when occupants experience symptoms linked to time spent in a particular building, but no single, specific illness or cause has been confirmed.

For building owners and facility managers, SBS should not be treated as a vague complaint or a quick reason to clean an air conditioner. It is a prompt to investigate how the indoor environment is performing. Ventilation, temperature, humidity, maintenance condition, occupancy patterns and pollutants can all contribute. The right response is evidence-based assessment, followed by targeted corrective work.

What Is Sick Building Syndrome (SBS)?

SBS describes a pattern: several occupants report non-specific symptoms while using a building or part of it, and those symptoms often improve when they leave. Common concerns include eye, nose or throat irritation, headaches, tiredness, dizziness, difficulty concentrating, dry skin and a feeling of stale air.

The term does not confirm that the building is the only cause of a person’s symptoms. Allergies, infections, workload, lighting, noise, stress and personal medical conditions may also be relevant. Equally, not every indoor environmental problem is SBS. A confirmed exposure to a particular contaminant, such as carbon monoxide or a recognised infection risk, requires a more specific investigation and response.

This distinction matters. Facility teams should take occupant concerns seriously without making assumptions about the cause. A structured investigation protects occupants, supports clear communication and avoids spending on work that does not address the actual problem.

Why SBS Can Affect Building Operations

Poor indoor conditions are rarely limited to comfort. In offices, people may report reduced concentration and more frequent discomfort complaints. In schools, hotels, retail premises and government facilities, the issue can affect user experience and confidence in building management. In industrial settings, heat, dust, process emissions and uneven airflow may add further complexity.

Complaints may also reveal a maintenance issue before it becomes more disruptive. A blocked outdoor-air intake, dirty supply duct, weak exhaust fan, incorrectly positioned diffuser or poorly balanced system can affect conditions in one zone while the rest of the building appears normal.

Malaysia’s warm, humid climate makes good HVAC operation especially important. Air conditioning systems must manage both temperature and moisture while supplying and distributing adequate outdoor air. When systems are poorly maintained, operated outside their intended design conditions or unable to match changing occupancy, discomfort can develop quickly.

Common Building Factors Behind SBS Complaints

There is seldom one universal cause. The investigation should consider the building as a connected system, not just the air conditioning unit nearest to the complaint.

Ventilation and outdoor air supply

Insufficient outdoor air can allow odours, carbon dioxide and internally generated pollutants to build up, particularly in densely occupied meeting rooms, classrooms and open-plan offices. The issue may result from incorrect control settings, blocked intakes, failed dampers, undersized systems or changes in the way a space is used.

More outdoor air is not automatically the answer. In humid conditions, increasing outside air without adequate dehumidification can raise indoor moisture levels and create a different comfort problem. The appropriate level depends on the building use, occupancy, system capability and local requirements.

Uneven airflow and temperature control

A room can meet the thermostat setting while still feeling uncomfortable. One area may receive too little supply air, another may be excessively cold, and stagnant corners may retain odours. Changes to partitions, furniture layouts, tenant fit-outs and occupancy can alter airflow patterns that were once acceptable.

Air balancing helps identify whether air is reaching each area at the expected volume and whether supply and return air are working together. It is particularly useful after renovation, system modifications or persistent complaints confined to certain zones.

Moisture, dampness and maintenance condition

Condensation, water leaks, blocked drain lines and poor humidity control can contribute to damp conditions. These should be investigated promptly, particularly where there is visible staining, persistent musty odour or deterioration of ceiling materials and finishes.

Dust and debris in ductwork, coils, filters and diffusers can also affect cleanliness and airflow. However, duct cleaning should follow inspection findings rather than become a routine explanation for every complaint. The condition of the system, the type of debris present and the likely source of contamination should guide the scope of work.

Indoor sources of pollutants and odours

Cleaning products, renovation materials, printer areas, pantry activities, tobacco smoke, vehicle exhaust near air intakes and kitchen emissions can all affect indoor air. Restaurants and commercial kitchens need particular attention because grease accumulation and ineffective exhaust can allow odours and contaminants to spread beyond the kitchen.

The timing of complaints often offers useful clues. A smell appearing after cleaning, during peak occupancy, after rain or when a nearby process operates can help narrow the investigation.

How to Investigate SBS Complaints Properly

The first step is to record the issue clearly. General statements such as “the air is bad” are understandable, but they are difficult to act on without details. Ask when symptoms occur, which rooms are involved, how many people are affected and whether complaints improve outside the building.

A practical investigation usually combines occupant feedback with a walkthrough inspection and HVAC review. Facility managers should examine recent changes such as renovation work, new furniture, revised operating hours, altered room use, cleaning products, water leaks or maintenance activities. These changes may be more relevant than the building’s age.

The following evidence is particularly useful when assessing a pattern:

• the location, dates and times of complaints;
• the number of people affected and whether symptoms ease away from the site;
• temperature, relative humidity and ventilation observations in affected areas;
• HVAC maintenance records, filter changes, breakdowns and control adjustments;
• photographs or notes of leaks, odours, visible dust, damaged insulation or blocked vents.

An indoor air quality assessment can then measure relevant environmental conditions and support a more objective review. The appropriate measurements depend on the complaint and building type. Testing without a clear question can produce data that is difficult to interpret, so the assessment should be planned around the observed issues.

Turning Findings Into Practical Action

Corrective work should match the confirmed or likely cause. If airflow is uneven, air balancing or diffuser adjustments may be appropriate. If filters are loaded or coils are dirty, planned air conditioning servicing may restore performance. Where inspection identifies accumulated debris in ductwork, robotic duct cleaning can help remove material from accessible internal surfaces while documenting the condition found.

For kitchens, the exhaust path deserves separate attention. Grease-laden ductwork and poorly maintained exhaust equipment are not only odour concerns. Regular kitchen duct cleaning supports safer operation and helps the exhaust system perform as intended.

Some actions are operational rather than mechanical. Adjusting occupancy schedules, keeping supply and return grilles clear, improving communication around renovation works or reviewing cleaning chemicals may reduce complaints without major system changes. A good contractor should explain what is known, what remains uncertain and why a recommendation is suitable.

When to Escalate the Issue

Urgent action is needed when occupants experience severe symptoms, when there is a suspected combustion-gas issue, a strong chemical odour, visible water damage, repeated leak events or possible exposure to a known hazardous substance. Isolate affected areas where appropriate and seek competent professional advice without delay.

For ongoing but less urgent discomfort, do not wait until complaints become widespread. Early assessment is usually more manageable than responding after staff morale, tenant satisfaction or business operations have been affected.

Aircond Clinic helps building teams assess indoor air quality, inspect HVAC conditions, measure airflow and carry out targeted cleaning or servicing where findings support it. The aim is not to offer a one-size-fits-all fix, but to help each building breathe healthier through practical, documented action.

A comfortable building is maintained through attention to patterns, not guesswork. When occupants raise recurring concerns, listening carefully and investigating methodically is one of the most effective ways to protect comfort, confidence and the long-term performance of the building.