That first blast of cold air when you walk into a hot hotel room feels like a small victory. But per pharmacy and hotel industry experts quoted by Metro UK and Bustle, that chilled breeze might come with a catch: if the unit hasn't been properly maintained, it could be circulating bacteria, mold and viruses straight into the room — and your lungs.
Clinical pharmacist Nyrah Saleem told Metro UK that a well-maintained air conditioning unit generally won't cause harm, but one that's ignored can. Water build-up inside an unmaintained unit creates a breeding ground for microbes and mold, raising the risk of infections. The phenomenon is common enough that travellers have coined names for it: Air Con Flu, Magaluf Flu and Ayia Napa Flu. Symptoms range from a stuffy nose, headaches and fatigue to breathing issues and skin irritation. In rare but serious cases, Legionella bacteria in cooling systems can cause Legionnaires' Disease, a severe form of pneumonia that needs antibiotics.
Air quality is the wider issue. A 2024 study in the Journal of Environmental Research and Public Health tested rooms in hotels of different star ratings across four US cities and found 57 of the 139 volatile organic compounds (VOCs) they screened for. The cheapest property tested — rated 2.5 stars — had the highest alcohol readings, a sign of heavy cleaning product use rather than cleanliness you'd want to breathe. The four-star room ranked lower on aromatics, suggesting that paying a bit more can buy you measurably better air. The US Environmental Protection Agency adds that indoor air can be far more polluted than outdoor air, and hotels are particularly prone to it thanks to constant guest turnover and windows that barely open, if at all. Some AC systems are even linked across multiple rooms, recirculating whatever is in the air back and forth.
So what can you actually do? The simplest step, according to former hotel manager Chris Johnston: leave the HVAC off if you can tolerate the heat, since switching on a unit with dirty filters pushes particles directly into the room. If that's not realistic in a tropical summer, there are workarounds. Check hygiene ratings before you book and favour properties with strong ones. It's entirely reasonable to ask hotel staff how often the AC systems are cleaned, or to request a fresh filter for your room. A portable travel air purifier is another option for sensitive travellers. And keep an eye on how you feel during your trip — though it's worth remembering that a holiday sniffle isn't always the AC's fault. You might have picked up a cold before you left home, or be reacting to pollen or something else entirely.
This matters for anyone booking a summer city break or beach escape, but especially for travellers with asthma, allergies or weakened immune systems. A two-minute check of hygiene reviews before booking — and a quick filter question at check-in — is a low-effort way to tilt the odds in your favour. Comfort and clean air don't have to be a trade-off; you just need to know what to ask for.
Via Explore.com.
