There’s no doubt that air conditioning can be a life-saver. The recent heat dome event over the Pacific Northwest shows how deadly high heat can be without air conditioning. While air conditioning might help you avoid heatstroke, it can also come with some risks of its own. People who spend much or all of their day in an air-conditioned environment can be at an elevated risk of some types of illness.
One of the features people promote about air conditioning is that it works as a dehumidifier, taking moisture out of the air. This can make the air feel more comfortable. However, the moisture that’s taken out of the air doesn’t just disappear; it condenses in or on the air conditioner unit. This creates a wet environment that can accelerate microbe growth either in the air conditioning unit or in places impacted by the dripping water. Of particular concern is black mold, which can grow in many areas with intermittent or constant wetting. Spores from black mold can be dangerous, even deadly.
Often, the water from air conditioners doesn’t stay in a cool area. It can drip out of the air conditioner in the warm outside air or into the casing in the hot part of the unit. This hot, wet environment is especially fertile for microbe growth. Then the air conditioner picks up and spreads the microbes whenever it blows air.
Many diseases are known to spread through heating, ventilation, and air conditioning systems, including measles, tuberculosis, influenza, and SARS. Air conditioning was the original source of Legionnaires’ disease. Early in the pandemic, there was significant evidence that air conditioning could encourage the spread of COVID-19. However, with proper configuration and maintenance (see below), air conditioning can actually prevent the spread of COVID-19.
In addition to growing microbes, an air conditioner can make you more vulnerable to the microbes that you inhale. While dry air from an air conditioner can feel more comfortable, it’s not always healthier.
You might have noticed dry, cracking skin from spending your days in an air-conditioned environment. This can be a painful nuisance, but it’s not the worst thing air conditioning’s dry air can do to you. You might have also noticed that your nose and throat can feel dry from spending time in air conditioning. This isn’t just uncomfortable; it can be dangerous. The mucus membranes in our nose and throat have an important role to play: they catch many bacteria and other microbes before they enter the body. In other words, your mucus membranes are your first line of defense against invasion. If they are too dry, bacteria and other microbes are free to pass into your body, where they can potentially infect you.
The cold, dry air fostered by air conditioning is also ideal for the spread of many viruses, including those for the common cold. In addition, air conditioning encourages people to gather around the unit, almost the exact way people congregate in the winter when colds and cases of flu can leap easily from person to person.
Because of the way that air conditioning can foster the growth of bacteria and then spread it around, central AC is often linked to sick building syndrome (SBS). SBS is when a building becomes the site of a high number of mysterious illnesses. These illnesses often feature common nonspecific symptoms like:
These symptoms spread through the building, though they may cluster in places where the air conditioning blows hardest or is set at the lowest temperature. Studies of SBS have shown that people might be up to 5 times more likely to develop certain types of illness if they spent much of their day in an air-conditioned environment.
On the other hand, air conditioning doesn’t have to make you sick. There are ways to reduce the risks of illness associated with air conditioning.
First, when you install an air conditioning unit, make sure it has access to clean air. One of the problems with air conditioning is that people congregate in areas where the same air is being recycled again and again, facilitating the spread of illness. You can also consider installing a UV purification unit, which has been proven to reduce the risk of AC-related illness.
It’s important to be aware of what happens to the water that condenses on or around the air conditioner. If your air conditioner has a tray to collect water, make sure it gets emptied regularly. Don’t let water accumulate near the air conditioner, travel to the warm side of the conditioner, or drip on the wall or floor of your house. If you do have a place where water sometimes drips, clean the area regularly with a bleach solution to discourage the growth of black mold.
Next, clean your air conditioner regularly. The dirt and dust that accumulates on an air conditioner’s condenser coils can be a source of fungus and other organisms that can make you sick. This dirt also serves to feed the microbes as they grow, letting them grow into large colonies. Regularly change air filters on the air conditioner.
Don’t set your air conditioner too low. You might think it’s comfortable to drop the temperature into the low 60s, but this temperature can make you more vulnerable to sickness. Finally, don’t spend all day in an air-conditioned environment. Take some time to get out of the building at lunch and on breaks.
You can also potentially avoid AC sickness by switching to a different cooling method, such as an evaporative cooler. An evaporative cooler doesn’t condense water; instead, it evaporates it. This means that an evaporative cooler isn’t going to accumulate water that overflows from the unit. A properly functioning evaporative cooler won’t lead to water accumulation unless you spill water while filling the unit.
An evaporative cooler also draws from a supply of fresh air, so it helps you turn over the air in your home or workspace. This reduces the concentration of microbes in your home and can help protect against the spread of illness.
An evaporative cooler humidifies the air, which can help your mucous membranes protect you from sickness, as well as keeping your skin from drying out.
While an evaporative cooler makes the air cooler, it doesn’t usually lead to the kind of cold temperatures that can make illnesses more likely.
Since 1990, Portacool has been making evaporative coolers at our Center, Texas manufacturing facility. We’ve become recognized leaders in the industry, and we have a good understanding of when air conditioning is the best choice and when it’s not.