Do dust mites make you sneeze every morning? Wake up stuffy-nosed every day? They could be living in your mattress. Dust mites live on mattresses, pillows, carpets, and upholstered furniture worldwide. One of the oldest tips for eliminating dust mites is to buy a dehumidifier. But will it really help? Here’s what the research says.
What Are Dust Mites?
Dust mites are microscopic arachnids. Technically, they’re cousins of spiders and ticks. You can never spot a dust mite with your naked eye. Each dust mite measures around .3 millimeters long. Your mattress could be home anywhere from 100,000 to 10 million dust mites.
They aren’t biting you. You’re allergic to their poop. Dust mites create a protein called Der p 1 in their fecal pellets. When you inhale it, your immune system may go into overdrive. If your body reacts to their poop, you’re going to experience allergic reactions like sneezing, itchy eyes, runny noses, and asthma attacks.
Their diet consists of dead skin cells that humans shed daily. It’s like a smorgasbord for them when they eat your skin cells off your body.
Why Humidity is So Important
Fun Fact: Dust mites can’t drink water from a glass or pool like we do. Instead, they absorb water from the air through their exoskeleton. So, it stands to reason that humidity plays a significant role in their lives.
Dust mites flourish in warm, humid environments. Most experts agree that they thrive the most at a humidity level between 70 and 80 percent. Temperature-wise, they prefer between 68 and 77 degrees Fahrenheit. Coincidentally, that’s why your bedroom is their favorite playground. Humans emit heat and moisture all night long while they sleep.
As the air around them becomes dry, dust mites struggle to gather enough water through their body. Without moisture, dust mites dehydrate and die. Researchers determined that at 75 percent humidity level, dust mites prosper and multiply at will. Below 50 percent humidity, their reproduction rate slows to a near crawl. When the relative humidity dips below 35 percent, dead mites begin to die off after days to weeks.
This direct correlation between humidity level and dust mites is precisely why so many people recommend a dehumidifier.
Dehumidifiers and Dust Mites – What does Science Say?
Research has confirmed this theory many times over. One study from 2000, published by the Journal of Allergy and Clinical Immunology, stated “Maintaining ≤45% RH reduced dust mite allergen levels by about one-half to two-thirds over 3 months.”
Research published in Science Direct agreed that maintaining relative humidity below 50% was one of the easiest ways to control dust mites within your home. When humidity was kept below that 50% mark consistently, mite populations went way down.
However, they add that to completely prevent dust mite populations of Dermatophagoides farinae from multiplying, you would need to maintain humidity levels below 35%RH for at least 22 consecutive hours each day.
Another study done by the National Center for Healthy Housing says dust mites don’t thrive at or below 60% relative humidity. Additionally, they say that lowering the moisture levels in your home makes your living spaces a lot less attractive to these pests.
The American Lung Association agrees with this method of dust-proofing your home. They recommend keeping your home’s humidity level below 50%. Moreover, they believe that using a dehumidifier and air conditioning unit can pull excess moisture from the air.
What should your humidity level be?
Experts recommend keeping your humidity level between 30-50% humidity.
As stated before, at 45% or below, dust mites have a hard time living. Their reproduction rate will plummet when the humidity level drops below that magic number. Although keeping your home around 35% will give you more aggressive results, some people may find this uncomfortably dry. NHS told us that dry air can irritate your sinuses and cause dry skin. Not to mention all the static electricity y’all would get.
So, what should you set your humidity levels at? A safe bet for the average person is around 40-45%. You can purchase a device called a hygrometer to measure your indoor humidity levels. The majority of smart-home platforms offer this feature nowadays, and many thermostats will measure it as well.
Why dehumidifiers alone won’t kill dust mites
Although dehumidifiers help prevent dust mites, they do have limitations.
It takes time. Dehumidifiers don’t work overnight. Studies have shown that it can take weeks or even months of running your dehumidifier to reduce allergens in your home.
Dead dust mites still cause allergies. Ok, so you kill all of your current dust mites with a dehumidifier. What about all the dead dust mites that have built up in your mattress, carpet, and furniture over the years? Dehumidifiers will help stop new dust mites from popping up but won’t remove the allergens that already exist. Remember to clean your sheets regularly and wash them with hot water when you can. Vacuum with a HEPA filter vacuum. Invest in dust mite-proof mattress and pillow covers.
Mites come back when you aren’t consistent. Let’s say you run your dehumidifier for a month and take a break. Bustle assured me that it could cause dust mites to return since one female can lay 40-80 eggs in her lifetime. If the humidity spikes for a week during the summer, you can undo all the work your dehumidifier did in just a few days.
Distribution – where you place your dehumidifier matters. Just because you bought a portable dehumidifier and placed it in your living room hallway doesn’t mean that the moisture is being sucked out of every room at the same rate. Research conducted in northwest England found that “a single centrally located dehumidifier was unable to lower humidity below 50%RH, or prevent dust mite population growth, in larger homes”
Case Study: Eliminating Dust Mite Allergens with a Dehumidifier
Family Overview: The homeowners had ongoing allergy symptoms including sneezing, congestion, coughing, and itchy eyes which were worse in the mornings.
Findings: Indoor environmental monitoring showed the relative humidity in the bedroom averaged between 68–72% causing optimal dust mite growth in mattresses, carpets, and upholstered furniture.
Solution: A portable dehumidifier was placed in the bedroom and humidity levels were monitored with a hygrometer. The family tried to maintain between 40–45% indoor relative humidity which dust mite research shows will greatly reduce their survival.
Results: By the end of the first week, the relative humidity had fallen to 45–48% RH and the dehumidifier was collecting several liters of water each day. The homeowners were also washing bedding weekly in hot water, utilizing dust-mite covers on mattresses and pillows, among other things.
Conclusion: Three months of keeping indoor humidity below 50% RH resulted in much lower dust mite allergen levels in the bedroom. Homeowners noticed less sneezing and itchy eyes in the mornings and better sleep.
Here’s the research article referenced in this article:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3966021/
FAQs
How do I prevent dust mites?
Dust mites love humidity. Keeping your home’s humidity below 50% relative humidity is recommended by most experts. For added protection and greatly slowing their reproduction, keep your home between 40–45% RH.
Will a dehumidifier kill dust mites?
Removing humidity from the air will eventually kill dust mites by depriving them of the water they need to survive. However, they will not get rid of existing allergens that have made their way into bedding, carpets, and furniture.
How long does it take for a dehumidifier to kill dust mites?
Some studies have shown that it can take several weeks to a couple of months of drying out the air to significantly reduce dust mites.
Where do I put a dehumidifier for dust mites?
Because dust mites like to live in mattresses, pillows, carpets, and upholstered furniture, you should put your dehumidifier in the bedroom or where your family spends the most time indoors.
Does humidity cause dust mites?
While there are many factors that contribute to dust mite growth, high humidity is one of the biggest. Dust mites tend to thrive and reproduce quickly once humidity rises above 60–70%.
What else can I do to control dust mites?
Along with controlling humidity, be sure to wash your bedding once a week in hot water (aim for 60°C/140°F), cover your mattress and pillows with dust-mite covers, vacuum with a HEPA filter vacuum and consider removing carpeting and heavy upholstered furniture.
Final Words
Do dehumidifiers prevent dust mites? YES! If you use them correctly, below 50% RH, your home is much less inviting for dust mites. However, you’ll want to pair your dehumidifier with weekly hot washes, vacuuming with a HEPA filter, and dust-mite preventive mattress & pillow covers for the best results.