Why Does Humidity Matter to You?

Humidity In The Summer

(image from

Do you hate the sticky feeling of humidity in the summer? The way it can make you miserable and hot? You can step out of the shower and instantly feel just like you did before the shower.

Or maybe you love the moisture, and you can’t stand dry air. Your skin just gets really dry. It cracks and itches. Your lips split and you spend the entire next week trying to get it to heal as it splits over and over again.

Chances are, you’ve gone through both sides of it. The negative effects of high humidity are often felt in the summer in humid climates, while the winter will usually dry the air out.

Humidity is the amount of moisture from water in the air. It can make you feel hot and miserable, or dry and itchy. But besides just making you uncomfortable, humidity is actually an important part of maintaining your health. Whether you love dry air or humid air, it’s important to know the risks from air that’s too dry or too humid. Before getting started, you might already be wondering what the optimum level of humidity is. According to the studies that support the information here, the best humidity level for your health is between 40% and 60%.

High Humidity Health Risks

If you’ve ever been somewhere more humid than you’re used to, you’ve probably felt how much hotter it feels when it’s more humid, even at the same temperatures. The extra moisture in the air makes it harder for your body to cool off by sweating. Because of this, your body can start overheating if you aren’t careful. The effects of overheating can start off with cramps, rashes, and exhaustion, which can all eventually lead to heatstroke.

But in addition to overheating, high humidity in the home can cause problems that lead to chronic health issues. This means that even for high humidity lovers, you need to be careful about allowing your home to be too humid.

High humidity promises you the following issues covered further below:

  • More numerous, bigger dust mites
  • Higher risk potentially dangerous mold and fungus growth in your home
  • Worse indoor allergy symptoms or asthma problems
  • Increased spread of infectious bacteria and viruses
  • Higher concentrations of volatile organic compounds in your air (VOCs)

To start, moist homes will worsen allergy symptoms from mites. That’s because mites, which are one of the biggest sources of indoor allergies, grow better in humid environments. You’ll get bigger mites and more of them. On the same note, molds and fungi also do better in humid environments, many of them needing at least 60% humidity to grow at all. Molds are an often overlooked cause of long-term health issues. If you live in a humid home and you deal with unsourced breathing or coughing issues (maybe using the word issues too much), it’s worth talking about your symptoms with a doctor.

Dust mites thrive in the humid homes

Dust mites thrive in humid homes (image from

If you suffer from asthma or severe indoor allergies, you’ll doubly want to avoid high humidity in your home to prevent making yourself any worse from dust mites and molds. And whether you have these conditions or not, there are additional reasons to keep humidity at more optimal levels.

Studies have also shown that humid environments are related to the spread of bacteria and viruses. The first reason is that certain bacteria and viruses thrive in humid conditions. The second is that people in humid conditions were found to have higher chances for infection. To be fair, it’s not clear from these studies if this chance is directly due to humidity or other factors such as poor ventilation, which can trap moisture.

On top of reducing bacteria and virus infections, avoiding extra moisture and keeping your home ventilated also helps you keep your home low in volatile organic compounds (VOCs). VOCs are organic chemicals that can come from regular household things like the varnish or paint used on your furniture and walls. The same study on bacteria and viruses showed that humid environments lead to higher concentrations of VOCs in your air.

If you love dry climates, all of this might sounds great for you. Unfortunately, however, the answer isn’t to keep your house as dry as possible.

Look Out for Low Humidity

Too much humidity sounds like a bad situation, but many of the same risks from high humidity are the same in really dry environments, too. Here’s what you still have when the humidity in your home starts dropping below 40%:

  • More numerous, bigger dust mites
  • Higher risk potentially dangerous mold and fungus growth in your home
  • Worse indoor allergy symptoms or asthma problems
  • Increased spread of infectious bacteria and viruses
  • Higher concentrations of volatile organic compounds in your air (VOCs)

Two out of five left. Not too bad, right?

But here are some bonuses you get from not having enough humidity:

  • Higher concentrations of ozone (O3) trapped indoors
  • Increased risk during respiratory infections
  • Dry, scaly, and itchy skin, which can lead to inflammation and sores

Starting with the same symptoms from before, how does dry air, like humid air, also lead to increased spread of bacteria and viruses?

Just like in high humidity, some bacteria and viruses thrive in dry conditions. You just can’t seem to win. And unlike humid environments, dry environments make it easier for droplets of viruses to float around in the air, which also increases the infection rate.

On the topic of chemicals in the air, although dry air reduces the level of VOCs in the air, you end up with more ozone in your air instead. Ozone can form in your home when VOCs react with other chemicals in sunlight, which is why there’s a direct trade-off between ozone and VOCs as you lower the humidity. Too much ozone can cause coughing, breathing issues, or irritation in your throat. Ozone is a common source of free radicals in the air, which lets it react freely with organic material like body tissue, leading to the health problems described.

Cold, dry air can make your coughing issues worse

Cold, dry air can make your coughing issues worse (image from

Another common concern about dry air is that it can dry out and irritate the sensitive lining of your nose, throat, and lungs. If you’re healthy, your body will do okay, but if you’re already sick or susceptible to respiratory infections, dry air can make it worse for you. So if you’re sensitive to respiratory issues from dryness, be sure to do some extra research on the best humidifiers for your needs.

One of the most direct health issues felt in dry places is dry skin. On top of just drying out your skin, dry air can make your skin scaly and itchy. If you have chronic skin issues like eczema or psoriasis, dry air can be absolutely horrible for your condition. With sensitive skin, you can get irritating bumps, rashes, or even blisters. And when you’re at home, using heating systems can dry out the air even further. Usually, you can solve skin issues with the right regimen of lotions or creams, but like with anything else, it’s better to address your problems at the source–in this case, the humidity level of the air.

What Can You Do?

Now, knowing about the different risks from humidity, here are some things you can do to deal with either high or low humidity.

Reducing Moisture in High Humidity Environments

  • AC or heating in your home will often dry out the air on its own
  • For very humid environments, consider using a dehumidifier to reduce the moisture in the air
  • Prevent humidity from making your home moist in the first place. Here are some common sources of humidity:
    • Cooking or boiling water, keep your pots and pans covered when you can
    • Laundry, vent your dryer to the outside or close any doors to your laundry machines

For really dry homes, you can consider doing the opposite of everything above.

Increasing Humidity in Dry Homes

An Air-O-Swiss humidifier

An Air-O-Swiss humidifier (image from

  • Consider installing a swamp cooler for the summer in very dry climates
  • Increase humidity by using a humidifier to maintain the best moisture levels for your health
  • Take advantage of regular sources of humidity at home
    • Leave cooking or boiling water open to the air to help humidify your home
    • Vent your dryer inside to improve humidity levels
    • Try out these other ways to humidify a room

Read More About Humidity


Arundel, A V et al. “Indirect Health Effects of Relative Humidity in Indoor Environments.” Environmental Health Perspectives 65 (1986): 351–361. Web.

Leon, L. R. and Bouchama, A. 2015. Heat Stroke. Comprehensive Physiology. 5:611–647.

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