Is Your AC Making You Sick?

Have you ever walked into a building on a hot day and been blasted by arctic air — only to suddenly find yourself sniffling, sneezing and feeling generally crummy?

It happens to a lot of people. It’s common enough, in fact, that it has a name: air conditioning sickness. But can air conditioning make you sick, or is it just a myth?

We asked pulmonologist Neha Solanki, MD.

Can air conditioning make you sick?

A properly maintained AC system is unlikely to make you sick on its own. But the atmosphere it creates — cooler air, lower humidity and recirculated indoor air — can sometimes influence your health.

“There’s nothing intrinsic about air conditioning that’s making you sick,” Dr. Solanki states. “It’s the atmosphere it creates that can lead to upper respiratory symptoms.”

It’s like when you feel sick when the weather fluctuates or the temperature outside suddenly changes. The world isn’t making you ill — your body’s just struggling to adapt to its new circumstances. Once it does, those symptoms will fade away.

How AC can contribute to feeling unwell

Your AC unit performs several different functions that change the quality of the air you breathe. Even though those changes are positive, they can still cause cold and flu symptoms while your body’s adjusting.

Air conditioning units act as a:

• Filter: Most AC units use filters to pull irritants out of the air, including allergens like dust, dander and pollen.
• Dehumidifier: When the air temperature in your home changes, so does the humidity level. AC units pass warm air over cooling coils that make the air condense and lose moisture.
• Circulator: Air conditioning helps keep air moving throughout your house, so it doesn’t feel stuffy. This constant circulation ensures that indoor air passes through the filter regularly.

You want your AC to change the conditions in your home — that’s why you have it! But when air quality shifts, your body’s bound to take notice.

Dr. Solanki shares the most common side effects of air conditioning.

Airway irritation

Chilly air from an AC unit can dry out and irritate your airways, leading to respiratory symptoms, like:

• Coughing
• Chest tightness
• Shortness of breath
• Sore throat

“Your respiratory tract, from your sinuses down into your lungs, is very sensitive,” Dr. Solanki explains. “When the air is too cold or too dry, it can trigger an inflammatory reaction and make breathing more difficult, especially for people with conditions like asthma.”

Dry skin and mucus membranes

A drop in temperature — and the corresponding drop in humidity — can dry out exposed skin and mucus membranes. In a heavily air-conditioned room, you may notice symptoms like:

• Dry skin
• Chapped lips
• Nosebleeds
• Dry or irritated eyes

If you’re already dehydrated, you may also notice symptoms like fatigue, headache, dry mouth and more.

What might make you more sensitive?

Anybody can react to a sudden change in temperature and humidity, but you’re more likely to be sensitive to air conditioning if you have:

• Asthma: “People with asthma are especially sensitive to low humidity,” Dr. Solanki notes. “The dry air can worsen inflammation and may trigger an exacerbation.”
• Certain autoimmune conditions: Sjögren’s syndrome, for example, damages the glands that produce moisture, causing dry eyes and dry mouth. “Those symptoms may worsen in air conditioning,” Dr. Solanki says.
• Health issues that cause congestion: Whether it’s the result of seasonal allergies, chronic sinusitis, nasal polyps or something else, you’re more likely to be sensitive to AC if you routinely deal with mucus buildup or drainage.
• Conditions that cause dry eyes: The combination of the air being drier and it circulating through the room can be painful for people with conditions that cause dry eyes, like blepharitis, diabetes and rosacea.
• Lung conditions: If you’re living with asthma, COPD, lung cancer or any other condition that affects your ability to breathe, changes in humidity and air quality could aggravate your respiratory symptoms.

Dr. Solanki notes that you may also become more sensitive to the effects of air conditioning as you age.

“Older adults’ kidneys may not conserve water as effectively as they used to,” she says. “It’s also common for your sense of thirst to decline with age. So, older adults may be less likely to up their water intake in response to dry air. They may also avoid drinking extra fluids due to worries about needing to pee more often.”

Taken together, these factors can make fluid balance a challenge for people over 65 in air-conditioned spaces.

Hormones also play a part.

“Women tend to have higher rates of eye dryness and mucosal dryness because of hormone fluctuations. That can make being in low-humidity spaces more uncomfortable,” Dr. Solanki adds.

Air conditioning and allergies

If you have allergies, air conditioning is both a friend and an enemy.

On the one hand, a good HVAC system filters out a lot of allergens in your home.

On the other hand, the constant churn of recirculated air means the allergens the filters don’t catch are always on the move. And if you aren’t maintaining your system, it can give rise to new ones, too, like mold.

“If you don’t have good filters in your air conditioning system, you’re just putting those allergens back into your living space on full blast,” Dr. Solanki warns.

Is ‘air conditioner flu’ real?

“Air conditioner flu” isn’t a real illness. Yes, a sudden change in your atmosphere could kick off symptoms that mirror an upper respiratory virus. But Dr. Solanki clarifies that there’s no germ specific to air conditioners causing you to feel unwell.

If they don’t, you may be dealing with a real virus — not a case of air conditioning sickness.

Preventing AC-related health concerns

If running your air conditioner leaves you feeling run down, there’s good news: Small changes can make a big difference for symptom management and your overall health.

“A lot of the variables that contribute to AC-related symptoms are actually controllable with home maintenance,” Dr. Solanki says.

You’re less likely to have a negative reaction to AC if you:

• Replace your filters as instructed. If your symptoms are flaring, replace your HVAC filter more often. And check to see if the filters you’re buying are certified Asthma & Allergy Friendly® by the Asthma and Allergy Foundation of America.
• Consider adding an air purifier. Even the best AC unit can’t filter all irritants out of your air. Having an air purifier in your bedroom can remove lingering particles while you sleep, which can help you wake up feeling rested instead of congested.
• Have your air ducts cleaned every three to five years. Getting built-up dust and debris cleared out of your HVAC system will help keep your AC unit running effectively and may improve indoor air quality.
• Do routine HVAC system maintenance. Ideally, you want your air conditioner inspected and serviced every year. If you notice a sudden uptick in your symptoms, that’s another reason to bring a technician around.
• Monitor humidity levels in your home. The U.S. Environmental Protection Agency (EPA) recommends keeping your home’s humidity level between 30% and 50%. If your house falls outside that range, Dr. Solanki recommends using a humidifier.
• Clean standalone or window units thoroughly (and often). “Many people tend not to be as good about the upkeep of these types of air conditioners,” Dr. Solanki notes. Yet these units can collect just as much dust, mold and other irritants, especially when they sit in storage over the winter.

Climate control should be a source of comfort — not one of cold and flu symptoms. If running your AC still does more harm than good despite proper maintenance, talk to a healthcare provider. What feels like “air conditioning sickness” could be an underlying health issue.