Can air conditioners make you sick? It’s a question more people are asking—especially as air conditioning becomes essential in homes, offices, and cars. The truth is, while air conditioners themselves aren’t inherently harmful, failing to maintain them can turn a comfort into a health hazard.
Dust, mould, bacteria, and other pollutants can build up inside your system over time. Without regular servicing, that same cool breeze meant to provide relief could be circulating airborne irritants into your living space.
Chris Schofield, an experienced AC technician, puts it plainly:
“When you skip servicing, you’re not just risking a breakdown—you’re risking your health. People don’t realise how easily mould and bacteria can take hold in a neglected unit.”
Let’s break down exactly what happens when you neglect your air conditioner, and the hidden dangers you may be inviting into your home.
1. Airborne Contaminants and Health Risks
Your air conditioner pulls in air, cools it, and redistributes it. In doing so, it also draws in:
- Dust and pollen
- Skin flakes and pet dander
- Bacteria and viruses
- Mould spores from humidity
A clean filter can catch most of these—but over time, even filters become clogged and ineffective if not replaced or cleaned.
When these pollutants build up and re-enter your living space, they can lead to:
- Respiratory irritation
- Sinus problems
- Allergies
- Asthma flare-ups
- Headaches and fatigue
2. Mould Growth in Ducts and Coils
Mould thrives in damp, dark environments—like the interior of an unserviced air conditioner. When condensation forms on coils or in drainage pans and isn’t properly drained, it creates a breeding ground for mould.
Once mould starts growing, spores can easily spread through your ductwork and into every room of your home.
Signs you may have mould in your AC:
- Musty or damp smells when the unit is on
- Allergy-like symptoms that worsen indoors
- Visible black or green spots near vents or drip trays
Regular maintenance helps prevent this by:
- Cleaning drainage systems
- Replacing filters
- Sanitising internal components
3. Increased Risk of Legionnaires’ Disease
While rare, poorly maintained air conditioning systems have been linked to outbreaks of Legionnaires’ disease—a severe form of pneumonia caused by Legionella bacteria.
These bacteria can multiply in stagnant water inside AC systems and then become airborne. Inhaling contaminated droplets can lead to infection, particularly in older adults or those with weakened immune systems.
Schofield warns,
“In large commercial systems or even home evaporative units, if water isn’t flushed and sanitised regularly, you’re creating the ideal conditions for bacteria to thrive.”
It’s a reminder that air conditioning isn’t just a mechanical system—it directly influences indoor air quality.
4. Poor Indoor Air Quality and Mental Fog
Even without mould or bacteria, a neglected AC unit filled with dust can significantly lower indoor air quality. This affects not only physical health but cognitive performance.
Dirty air can lead to:
- Difficulty concentrating
- Daytime drowsiness
- Irritability or mood swings
- Dehydration and dry skin
For those working from home or spending long hours indoors, this can have a real impact on productivity and quality of life.
A clean unit circulates fresh, filtered air, which helps regulate temperature, reduce allergens, and maintain healthy humidity levels.
5. Overheating and Electrical Hazards
Neglected units don’t just risk your health—they can become fire hazards.
Dust buildup around electrical components, frayed wires, or blocked airways can cause:
- Overheating compressors
- Short circuits
- Electrical sparks
In worst-case scenarios, these can lead to house fires. A quick servicing can identify and prevent these issues long before they escalate.
Schofield notes,
“We’ve seen units so choked with dust they started tripping circuit breakers every week. One had a wire melted through. That could’ve ended in disaster.”
6. Reduced Efficiency and Higher Energy Bills
Aside from health concerns, failing to service your air conditioner also affects your wallet.
When your system is dirty or struggling to operate:
- It has to run longer to cool your space
- It consumes more electricity
- Components wear out faster
The result? Higher energy bills and more frequent repairs.
Routine maintenance:
- Improves airflow
- Ensures components work properly
- Extends the life of the unit
In most cases, a professional service once or twice a year pays for itself through energy savings and better performance.
7. AC-Related “Sick Building Syndrome”
In shared environments like offices, schools, or apartment complexes, unmaintained air conditioners can contribute to Sick Building Syndrome (SBS)—a condition where people experience symptoms that seem linked to time spent in a particular building.
These symptoms often include:
- Headaches
- Dry throat
- Coughing or sneezing
- Nausea
- Skin irritation
And they typically improve once people leave the building.
AC systems that aren’t regularly cleaned or serviced are common contributors, especially when multiple units share the same air circulation pathway.
So… Can Air Conditioners Really Make You Sick?
The short answer: yes—if they’re not properly maintained.
Your air conditioner should improve your comfort and indoor air quality, not undermine your health. Regular servicing ensures that:
- Filters are clean
- Coils and fans are free of mould or dust
- Drainage systems are clear
- Airflow is safe and efficient
Chris Schofield drives the point home:
“You wouldn’t drink from a dirty water bottle. So why breathe air coming from a dirty machine every day?”
How Often Should You Service Your Air Conditioner?
As a general rule:
- Split systems and ducted units: at least once a year
- Evaporative systems: before and after summer use
- High-use environments (offices, medical spaces): every 6 months
Don’t forget to clean or replace filters every 1 to 3 months, depending on usage and air quality.
Final Thoughts
Neglecting your air conditioner might save time or money in the short term—but the long-term cost could be your health, your safety, and your wallet.
Whether you’re running a home system or managing a commercial property, regular servicing isn’t optional—it’s essential. Because when it comes to air quality, what you don’t see can hurt you.
So, the next time you ask, “Can air conditioners make you sick?”—remember that the answer depends entirely on how well you maintain them.
As Chris Schofield, seasoned AC technician, says:
“Air conditioning should be about comfort—not compromise. A little maintenance now saves you from a lot of regret later.”
