Reviewed by the Air Cool Care technical team — Perth-based HVAC and indoor air quality specialists serving Wanneroo, Joondalup, and surrounding suburbs for 15years. Based on hands-on experience assessing air quality in Perth homes and offices.
If headaches, fatigue, or a scratchy throat seem to clear up the moment you leave the office — and come back the moment you walk back in — you’re not imagining it. This pattern has a name: sick building syndrome, and it affects a surprising number of Perth workplaces with sealed windows and ducted air conditioning running most of the day.
The short answer: Sick building syndrome is largely preventable by improving three things — ventilation, filtration, and regular HVAC maintenance. Buildings that rely on sealed, recirculated air without adequate fresh-air exchange or clean ductwork are the most common source of the symptoms. Below are seven practical, evidence-based steps that reduce the risk.
What Is Sick Building Syndrome?
Sick building syndrome (SBS) describes a set of symptoms — headaches, eye and throat irritation, fatigue, difficulty concentrating, and respiratory irritation — that occupants experience while inside a specific building, with symptoms easing or disappearing after they leave. Unlike a single diagnosable illness, SBS is linked to the building environment itself: poor ventilation, contaminated ductwork, off-gassing materials, or inadequate humidity control.
Offices, especially those with sealed windows, centralised ducted air conditioning, and open-plan layouts, are among the most commonly affected environments.
1. Improve Fresh Air Exchange, Not Just Recirculation
Many commercial HVAC systems are set up to recirculate indoor air with minimal fresh outdoor air brought in, which conserves energy but allows CO2, volatile organic compounds (VOCs), and airborne particles to build up over the day. Where possible, increasing the fresh air intake ratio on the system — even during business hours when the building is occupied — measurably reduces the concentration of indoor pollutants.
If you’re not sure what your building’s current fresh air ratio is, this is worth raising with your HVAC technician at the next scheduled service.
2. Clean and Inspect Air Ducts Regularly
Ducted systems that haven’t been cleaned in several years can accumulate dust, mould, and debris that gets circulated through the building every time the air conditioning runs. This is one of the most common and most fixable contributors to sick building syndrome in Perth offices, particularly in older buildings or those that have never had a professional duct clean.
A professional air duct cleaning service removes this buildup at the source, rather than relying on filtration alone to compensate for a dirty system.
3. Maintain Filtration Appropriate to Occupancy
Standard HVAC filters are often sized for basic dust capture, not the finer particulate’s and allergens that affect sensitive occupants. Upgrading to a higher-rated filter — and replacing it on schedule rather than waiting until it’s visibly clogged — significantly improves what actually gets removed from circulating air.
Our air filter replacement service can advise on the right filter rating for your building’s occupancy and layout.
4. Control Humidity Levels
Both very dry and very humid indoor air contribute to SBS symptoms. Low humidity dries out eyes, throat, and skin; high humidity encourages mould and dust mite growth inside ductwork and on surfaces. Perth’s climate swings between dry summer heat and humid winter conditions, so HVAC systems need to be actively managing humidity rather than just temperature.
5. Address Mould and Moisture Sources Promptly
Water stains, musty odours, or visible mould around vents, ceiling tiles, or window seals are a direct contributor to poor indoor air quality and should never be left unaddressed. Mould spores circulated through a ducted system affect the entire building, not just the room where the moisture originated.
If you notice any of these signs, a professional inspection should happen before the next service call, not at it.
6. Reduce Indoor Pollutant Sources
New carpet, furniture, paint, and cleaning products can off-gas VOCs for weeks or months after installation or use. Choosing low-VOC materials where possible, ventilating well after any renovation or new furniture delivery, and using fragrance-free cleaning products all reduce the chemical load on indoor air.
7. Schedule Preventive HVAC Maintenance, Not Just Repairs
The single biggest factor separating buildings with chronic SBS complaints from those without is whether HVAC maintenance is scheduled proactively or only happens when something breaks. Regular servicing — checking coils, drainage, ductwork, and filtration together — catches the small issues that compound into building-wide air quality problems before occupants start noticing symptoms.
Signs Your Building May Have an Air Quality Problem
- Headaches, fatigue, or irritated eyes/throat that improve after leaving the building
- Musty or stale odours, especially when the HVAC system first switches on
- Visible dust around vents or a noticeable increase in dust on surfaces
- Complaints clustering in specific rooms or zones rather than the whole building
- It’s been more than 2-3 years since the last professional duct clean or filter service
Frequently Asked Questions About Sick Building Syndrome
What are the most common symptoms of sick building syndrome?
The most common symptoms are headaches, fatigue, eye and throat irritation, difficulty concentrating, and respiratory irritation. A key indicator is that symptoms ease after leaving the building and return upon re-entry.
Can duct cleaning really prevent sick building syndrome?
Duct cleaning addresses one of the most common contributing factors, dust, allergens, and mould circulating through a building’s ductwork. Combined with proper ventilation, filtration, and humidity control, it’s a significant part of prevention, though not the only factor.
How often should office HVAC systems be serviced to prevent SBS?
Most commercial systems benefit from professional duct cleaning every 2-3 years and filter checks every 1-3 months, though buildings with higher occupancy or older systems may need more frequent servicing.
Is sick building syndrome only a problem in offices?
No. While it’s more commonly discussed in commercial buildings due to sealed windows and centralised systems, homes with poor ventilation, uncleaned ducts, or moisture issues can produce the same symptoms.
The Bottom Line
Sick building syndrome isn’t an unavoidable side effect of modern office buildings — it’s usually a sign that ventilation, filtration, or ductwork maintenance has fallen behind. Addressing the seven areas above, starting with a professional inspection if it’s been a few years since the last one, resolves most cases at the source rather than masking symptoms.
Servicing Wanneroo, Joondalup, and surrounding Perth suburbs. Learn more about our indoor air quality services or get a free quote today.