What is Air Conditioner Lung?

Have you ever found yourself coughing when your air conditioner is running? The problem might be a condition called hypersensitivity pneumonitis; it goes by multiple nicknames, including air conditioner lung. If you feel like you have the flu and you cough and experience shortness of breath a few hours after turning your AC on, your unit may be the culprit.

Let’s learn more about what AC lung is, what causes it, and how you can avoid symptoms.

What is air conditioner lung? 

Besides being a mouthful, hypersensitivity pneumonitis is an inflammation of the lungs and presents as an immune system disorder. Anyone with allergies is likely familiar with the inflamed feeling that takes place in the lungs after breathing in pollen, dust, cat fur, or whatever it is that makes you wheeze. Similarly, air conditioner lung is an allergic reaction that stems from breathing in allergens like dust, mold, fungus, and other pollutants. These contaminants can enter your lungs and make you sick.

What causes air conditioner lung?

The primary cause of AC lung is mold. Mold thrives in a damp environment, so any time your air conditioner collects standing water, it could lead to a moist, moldy mess. 

Although your mental image of mold might be visible fungus-like growth, mold also spreads through microscopic spores that we can’t see with the human eye. These spores travel through the air and can enter your lungs, causing sickness ranging from minor sniffles and sneezes to major issues breathing.

Out of the different molds that might grow in your air conditioner unit, the most dangerous is black mold, or Stachybotrys chartarum. This microfungus can cause severe issues, including lung bleeding. There are also causes of hypersensitivity pneumonitis that are unrelated to your air conditioner: 

• mold from hay, straw, and grain (the condition is also called farmer’s lung)
• bird feathers and droppings
• bacteria in water vapor from indoor hot tubs

What are the symptoms of air conditioner lung?

Air conditioner lung symptoms may vary, but they generally include:

• a dry cough or wheeze
• the inability to catch your breath
• a feeling of tightness in the chest
• fever
• chills
• fatigue
• headache

Symptoms of air conditioner lung typically appear four to six hours after exposure to the allergen and may last anywhere from 12 hours to a few days. The symptoms of A/C lung are similar to those of COVID-19, so it’s probably a good idea to get tested for COVID if you experience any of the symptoms.

How dangerous is air conditioner lung?

Thankfully, if caught early, hypersensitivity pneumonitis can usually be reversed. According to the American Lung Association, visiting your doctor at the first sign of air conditioner lung can mean a better chance of full recovery.

If left untreated, A/C lung can cause scar tissue to develop. Lung scarring is a life-long condition that can lead to trouble breathing and other ongoing issues.

How is hypersensitivity pneumonitis treated?

After learning about this condition, you may be wondering how to treat air conditioner lung. It is usually diagnosed through a physical exam. A series of tests—generally including a chest X-ray, a lung function check, blood tests, and a bronchoscopy—will be conducted to confirm the diagnosis. 

Following diagnosis, your doctor will likely recommend a steroid treatment plan. Avoiding exposure to the allergens that caused the condition is also a vital part of air conditioner lung treatment.

How do I keep my air conditioner from getting me sick?

First, it's helpful to understand how air conditioning works. Be sure to check your air conditioning unit and surrounding areas for standing water. Make sure to empty your A/C unit's water reservoir regularly to prevent mold from developing. Units may leak because of a frozen evaporator coil, a clogged drain line, a rusty drain pan, or a low level of refrigerant. If you notice any smells coming from your AC, it could indicate mold growth. Regularly cleaning your AC unit condensate drain line can help prevent this health hazard from burgeoning.

You should also change your air conditioner filter regularly to prevent mold buildup. For fiberglass filters, you should try to change the filter out every month. An easy way to remember to change your filter is to set a reminder on your phone for the first day of every month. Pleated filters may last up to six months, but you should always make sure to read the filter instructions so that you don’t accidentally let too much time go by between filter changes.

The most important step you can take to avoid AC lung is to ensure that your air conditioner unit is properly maintained so that the air in your home is as clean as possible. Signing up for an American Home Shield® home warranty plan means that you’ll have air conditioning warranty coverage. If your unit experiences an issue due to wear and tear, it will be repaired—and if we can’t repair it, we’ll replace your AC unit, subject to the limitations and exclusions of your contract. That’s not all—ShieldPlatinum™ members get one free HVAC tune-up per contract term, and ShieldGold™ and ShieldSilver™ members have access to HVAC tune-up services that can be booked directly in MyAccount.

Don’t let air conditioner lung get in the way of your day-to-day. Make sure you keep your unit in tip-top shape, and if you notice symptoms, contact your doctor immediately. 

AHS assumes no responsibility, and specifically disclaims all liability, for your use of any and all information contained herein.