When summer hits, the air conditioner becomes your best mate. It keeps things cool when stepping outside feels like walking into an oven. But while you’re soaking up that sweet, chilled air, there might be something less pleasant coming along for the ride — and you can’t always see it.
The truth is, if your air conditioner hasn’t been cleaned in a while, it could be doing more harm than good. A build-up of dust, mould, or bacteria inside the unit doesn’t just mess with how it runs — it can also affect your health. Here’s a look at five common health problems that can be linked to a grubby aircon.
1. Breathing Problems and Allergies
This one’s a biggie. Dirty air conditioners often end up full of dust, pollen, mould spores, and all sorts of airborne junk. Every time you turn it on, those particles get pushed into the air and straight into your lungs.
People with asthma or hay fever usually feel it first — sneezing, coughing, itchy eyes, or a tight chest. But even if you don’t have allergies, breathing in that kind of air over time isn’t doing you any favours. Some people notice they wake up stuffy or with a dry throat after sleeping with the aircon on — that’s often a sign the unit needs a clean.
Regularly cleaning your aircon filters is one of the simplest and most effective ways to cut down on airborne irritants and improve your indoor air quality.
It’s especially important to stay on top of this if you’ve got kids or elderly folks at home. Their immune systems don’t cope as well with polluted air.
2. Skin feels dry and itchy
Ever felt your skin feel tight or flaky after hours in an air-conditioned room? Not your imagination.
Air conditioners remove moisture from the air which can dry out your skin. But when the system is also full of dust and grime it can spread irritants that make things worse — especially if you have sensitive skin or eczema.
Some people have reported getting rashes or random itchiness after sitting near a dirty vent. It doesn’t always scream “aircon problem” right away but it’s worth checking when nothing else seems to explain it.
3. Sore, Red, or Dry Eyes
If you’ve ever rubbed your eyes after sitting near the aircon and felt like you’ve been cutting onions, you’re not alone. Eye irritation is surprisingly common when the air conditioner isn’t clean.
It happens for a couple of reasons: the air gets really dry, which messes with your tear production, and airborne irritants can float right into your eyes. If you wear contacts, it’s even worse — your eyes are already working harder, and dirty air just adds fuel to the fire.
A few hours of that and it’s no wonder your eyes end up feeling gritty or bloodshot.
4. Random Headaches and Feeling Wiped Out
Ever walked out of the office or your bedroom and felt instantly better after having a dull headache or just feeling flat? Believe it or not, your air conditioner might be the sneaky culprit.
When filters are dirty, the air quality takes a dive. On top of that, if your unit hasn’t been cleaned properly, it can push out tiny pollutants or even chemical fumes from VOCs (volatile organic compounds) that build up in enclosed spaces.
Some people experience this as part of “Sick Building Syndrome” — feeling off in one place and fine everywhere else. If headaches or general sluggishness seem to go hand-in-hand with aircon use, it might be time to give your unit a proper once-over.
5. Catching Bugs More Easily
This one’s a bit more serious. A poorly maintained air conditioner can actually spread bacteria, and in some cases, even nasty infections. One of the more well-known ones is Legionnaires’ disease, which can develop when bacteria builds up in stagnant water inside the system.
Now, this is more of a concern in larger or older systems — especially in commercial buildings — but it’s still something to be aware of at home. Even mould, which can grow in filters and ducts, can trigger chest infections or make you more prone to getting sick.
If the air coming from your system smells a bit off — musty or damp — that’s usually a warning sign. Don’t ignore it.
So, How Often Should You Clean Your Aircon?
Short answer: more often than most people do.
Here’s a quick guide:
- Filters: Give them a clean every 2–3 weeks if you use your aircon regularly.
- Professional Service: At least once a year — ideally before the hot weather kicks in.
- Ducts (for ducted systems): Every few years, or if you notice dust build-up, bad smells, or weak airflow.
If you’ve got pets, live near a construction site, or use the unit nearly every day, bump those timelines up. Trust your nose too — if something smells off, it probably is.
Why Aircon Hygiene Matters
We tend to think of air conditioners as purely mechanical — they’re either working or not. But the air they pump out ends up in your lungs, your eyes, on your skin. So if the unit is dirty, it doesn’t just affect performance — it affects your health.
Taking the time to clean the filters or book in a proper service might not seem urgent, but it can stop you from getting sick, save you money in the long run, and make your home a much more comfortable place to be.