Are dehumidifiers good for asthma?

Are dehumidifiers good for asthma? Young girl using inhaler
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Whether you're the type of person who loves the heat, or you thrive in colder temperatures, when the air gets humid in the summer, we can all find ourselves struggling to breathe normally. Humidity refers to the amount of moisture in the air. When humidity levels reach over 50%, we tend to suffer from the heat (opens in new tab) more than usual, as the moisture in the air prevents our sweat, the body's cooling mechanism, from evaporating.

Because high humidity can be so uncomfortable, especially in hot temperatures, many families invest in a dehumidifier to reduce the humidity levels in their homes. Dehumidifiers use a fan to essentially suck excess moisture out of the air and release drier air back into the room, thereby rebalancing your home's humidity levels.

While most people use dehumidifiers to make their homes feel a little cooler and fresher in the summer, you may be surprised to learn that the machines can also be useful for people with asthma. Today, we'll be discussing how the best dehumidifiers can help to ease the symptoms of asthma and why, along with some tips on how to use a dehumidifier to breathe a little easier when things get humid.

Is a dehumidifier good for asthma?

Asthma (opens in new tab) is a frustrating, persistent condition in which a physical abnormality of the lungs results in sensitivity and occasional breathing difficulties. Environmental triggers and excessive bursts of cardio can cause the common symptoms of an asthma attack, such as a cough, wheezing, chest tightness, and breathlessness.

Asthma is a chronic condition that is untreatable, however, doctors can help asthmatic patients manage the condition with education about the common triggers, advice on possible lifestyle changes, and medication. One of the lesser-known tools that can be used in the battle against asthma is a dehumidifier. 

Are dehumidifiers good for asthma? Image of woman sitting with door open

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How is a dehumidifier good for asthma?

As Dr. Jessica Shepherd, Chief Medical Officer of Verywell Health (opens in new tab), told Live Science, dehumidifiers are not recommended as the only tool to manage asthma, but in certain cases, they can be useful. "Dehumidifiers should not be used to manage asthma, however, yes, they can ease asthma symptoms," she says.

As Shepherd explains, dehumidifiers are only useful if high humidity is a factor that is aggravating your asthma.

So far, the scientific evidence on the benefits of dehumidifiers for asthma shows that Shepherd's assessment is pretty spot on: while they can help, they are certainly not all that useful during periods of "normal" humidity levels. 

A 2013 double-blind study from the Cochrane Database of Systematic Reviews (opens in new tab) on the effects of mechanical dehumidifiers on asthmatic patients showed that dehumidifiers made no noticeable impact on asthma control.

• Related: Dehumidifiers on sale (opens in new tab)

However, as the Asthma and Allergy Foundation of America (opens in new tab) notes, high temperatures and thicker air can negatively affect your breathing, which can, in turn, lead to lung irritation and breathing problems. As Shepherd adds, "Heat and humidity create changes in the air which will increase the demand for oxygen. It is also important to monitor the humidity level, especially in the home, with a hygrometer as humidity levels that are over 45% encourage mold, bacteria, and dust mites growth - all of which are common asthma triggers." 

Because of the effects of humidity on asthma, it follows that a dehumidifier could be a useful tool for people who struggle with asthma attacks during the hotter months. However, there's a reason why dehumidifiers aren't considered a standard tool for managing asthma - dry air can also aggravate the lungs. So, to avoid doing more harm than good, dehumidifiers should only be used to help with asthma when the air is extremely damp.

Are dehumidifiers good for asthma? Picture of woman taking in fresh air on balcony

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Is humidity or dryness best for asthmatics?

Many doctors actually avoid recommending dehumidifiers to asthmatic patients, simply because they can make the air excessively dry if used at the wrong time.

As Dr. David Edwards, FEND (opens in new tab) Inventor, pioneering aerosol scientist (opens in new tab), and Harvard University faculty member, notes, while humid air can be bad for asthmatics, dry air can actually be worse. "At low humidity, the upper airways, which necessarily hydrate inhaled air, can dry out, slowing cilia beat frequency that is critical for clearing inhaled debris, and stressing cells," he says. "Low humidity also promotes breakup of mucus into respiratory droplets, which can carry inhaled contaminants deeper into the airways where they can promote respiratory illness including bronchoconstriction."

Edwards points to a peer-reviewed 1977 study from the Journal of Allergy and Clinical Immunology (opens in new tab) that found that exercise-induced asthma (EIA) occurs more frequently in dry air than in humid air. The study even noted, "High humidity of inspired air could be the reason why EIA is less prevalent in swimming, as compared with other modes of exercise." In other words, it's more important to avoid dryness than humidity as an asthmatic. In fact, a little moisture in the air can actually help to ease the symptoms of asthma. 

So, it's best to avoid using a dehumidifier in your home unless you're absolutely sure that the internal humidity levels are above the optimal levels of 40-60%. While dry air may be worse for asthma than humid air, both come with their challenges. As Edwards sums up, "It is very important to maintain a moderate humidity in the control of an air space — whether by dehumidifying a very wet room or humidifying a very dry room."

What are other methods for managing humidity-induced asthma?

While dehumidifiers can certainly help to ease any humidity-induced asthma attacks, they will always work best alongside other medically approved methods for asthma management. As Shepherd notes, these include:

  • Reducing exposure to allergens or irritants that trigger asthma 
  • Getting an annual flu shot 
  • Weight management 
  • Limiting exposure to any allergens including pollen, dust, mold, and pet dander. 
  • Avoiding smoking of cigarettes, vaping
  • Breathing exercises such as the Buteyko technique

Are dehumidifiers good for asthma? Woman blowing her nose

(Image credit: Getty)

The takeaway

Asthma is a complicated chronic condition. Managing your symptoms requires a careful plan, and experience of your unique environmental triggers. While dry air is widely known to aggravate asthma, excessive levels of humidity in your home can also lead to irritation or an attack. Take note of the humidity levels in your home when you tend to experience symptoms. If you notice a pattern related to high humidity, it may be a sign that a dehumidifier could be just the thing you need to keep your symptoms in check.

Meg Walters
Freelance Writer

Meg Walters is a freelance journalist and features writer. Raised in Canada and based in South East London, Meg covers culture, entertainment, lifestyle, and health. Her work has appeared in Cosmopolitan, i-D, Refinery29, Stylist, GQ, Shondaland, Healthline, HelloGiggles and other publications.
When she's not writing, Meg is probably daydreaming about traveling the world, re-watching an old rom-com with a glass of wine, or wasting time on Twitter, where you can follow her @wordsbymeg.