When that telltale dry skin and congestion hits during dry weather, the most direct solution is to get a humidifier. But is there such a thing as too much humidity? And how do you know how low to set the machine?
It turns out that, yes, there is such a thing as too much humidity in the home. Having the humidifier on too high can lead to mold and mildew growth in the worst cases. Similarly, having it on too low might lead to not getting the best effects from the humidifier. Learn about the optimal humidifier settings and when it might make sense to even get a humidifier.
The ideal humidity level for a good night’s sleep
Humidity is shockingly important for sleep. In fact, too much humidity can cause problems with sleep. The Sleep Foundation states that having too much humidity can actually cause problems with staying in slow-wave NREM and REM sleep. NREM sleep can help with tissue repair, bone/muscle recovery and immune health. Meanwhile, REM sleep helps with memory consolidation.
Further, a study in the journal Biological Rhythm Research found that high humidity can negatively affect sleep. That humidity was also in temperatures above the thermoneutral zone, which is the range of temperature where metabolism can provide enough heat to maintain a constant body temperature. Another study in the International Journal of Biometeorology found that humid heat exposure in particular can have a negative effect on sleep.
The ideal amount of humidity can vary depending on the source. One study in the publication Building and Environment listed 40-60% as the ideal relative humidity. The University of Minnesota Extension lists optimal ambient humidity at 25% in winter and 50% in summer. The EPA states you should ideally keep relative humidity between 30-50% to prevent mold and mildew, while certainly having humidity below 60%.
In general, try to keep your home at between 30-50% relative humidity. Take note of how you feel at different humidity levels, keeping an eye out for any signs of dryness like itchy skin or parched airways. Up the humidity levels if need be, but never have them at 60% or more.
If you’d like to get more humidification in your home, follow the steps below:
1. Figure out if a humidifier is really right for you
You may have to adjust humidity levels based on your local climate. A dry climate may make you feel more comfortable with higher humidity indoors, for instance. You should also be aware of any dust allergies, as a humidifier can cause optimal conditions for dust mites to live.
If a humidifier is not a possibility, you might look into turning down the heater, as heaters can dry out the air. If you live in a climate with some humidity, you might also consider opening a window periodically.
2. Shop for humidifiers
If you decide a humidifier is right for you, research the different types of humidifiers. You might find you prefer a tabletop model or a standing floor model. There are cool-mist and warm-mist humidifiers. Humidifiers also have ratings based on how many square feet they can cover.
3. Learn the control settings and set them to desired humidity level
Higher-end humidifier models allow you to preset the humidity level you want by setting the percentage, such as if you want 45% humidity. These are often referred to as programmable.
Some machines will have a more general humidity level you set, such as a 1-5 setting. The machine will run until the area reaches that humidity level and then shut off. You might also see settings for fan speeds and other customizable features.
With lower-feature humidifier models that don’t tell the humidity percentage, you may have to buy a humidity gauge for your home, also known as a hygrometer, in order to measure humidity levels yourself. Many can also show the temperature.
Signs the air in a bedroom is too humid or too dry
Even if you don’t have a digital tool to tell you how humid your house is, there are other ways to tell if your home is too humid or too dry. The signs below might also help you adjust to your preferred humidity level.
Telltale signs your bedroom is too humid
- You notice more mildew or mold. According to the EPA, you might notice a moldy odor. Here are some tips for getting a musty smell out of a room.
- Your home has blistering paint. The University of Minnesota Extension lists peeling, cracking and blistering paint on both interior and exterior surfaces as a sign of excess moisture in the home.
- You notice worsening allergy symptoms. If your humidifier is on too high or contributing to other moisture in the home, you might notice an uptick in dust and mold allergies from the humidifier, according to the American Academy of Allergy, Asthma and Immunology. Dust mites and mold can grow in high moisture areas.
- You see condensation. The University of Minnesota Extension also lists condensation on the windows during winter as a sign of excess home moisture.
Telltale signs your bedroom is too dry
- You’re feeling dry eyes, mouth, skin and nose. One study in the International Journal of Hygiene and Environmental Health looked at indoor humidity and health. It found that higher humidity might help resolve complaints of dry eye in particular. According to Anderson Air, people also complain about dry mouth, dry skin and dry nasal passages when the humidity is not high enough.
- You’re thirstier than usual. Feeling like you’re sucking down more fluids than usual? Dry air can contribute to thirst.
- Your allergies are being triggered. Allergies can go the other way, too, and affect you more in air that is too dry. One study found that allergic rhinitis was triggered in both high and low relative humidity.
- Your wooden furniture and flooring show heat damage. Anderson Air reports that dry air can cause moisture to evaporate from the home, leaving wooden walls, floors and furniture to fracture, peel, creak, crack or warp.
- You’re getting shocked more often. Static electricity can also be more noticeable in dry homes, which is why you may notice more static in winter.
What to do (and to avoid) in order to maintain optimal bedroom humidity
Since humidity can so directly affect sleep, you’ll want to follow the below dos and don’ts for keeping optimal humidity in the bedroom.
Things you should do
Things you should avoid
Common questions about humidity and sleep
Technically neither is a good option. Too dry of a room can cause issues like dry skin, thirst/dry mouth and dried-out nasal passages. Both too much and too little humidity can cause issues like home damage in the form of warped wood or blistered paint. Worsening allergy symptoms can crop up from poor humidity modification. Too much humidity can cause the dreaded mold and mildew. Try to keep room humidity between 30-50%.
The EPA states that 60% or above is the territory where room humidity is problematic. At that point, you risk damaging building structures and furnishings as paint blisters. You might start to notice mold and mildew growth, too. Condensation may start on windows or other surfaces. Plus, the home environment might feel downright muggy and uncomfortable.
High humidity, especially warm weather humidity, can actually disrupt sleep. According to the study mentioned above, high humidity can harm sleep quality. The Sleep Foundation states that high humidity can even interrupt key stages of sleep that help us recuperate, such as the REM sleep stage, which helps us organize our memories.
Dry air can’t cause snoring, but it may make snoring much worse. The Sleep Foundation lists nasal congestion as contributing to snoring, which can be caused by dry air. When interviewed by The New York Times, otolaryngologist Dr. Jolie Chang stated that a humidifier can help with sleep by adding moisture to the nose and throat, but it probably won’t clear up the snoring.
Humidifiers can help with congestion. The National Library of Medicine states that a humidifier can help relieve a stuffy nose and break up mucus. Congestion may also come from dry air, as dry air can irritate and inflame the airways in both your nose and throat. Adding a humidifier can be an easy way to see if dry air is what’s causing your stuffy nose at night.
Wrapping it up
Most reliable sources recommend keeping your home’s humidity around 30-50%. Anything significantly lower could dry out your airways and lead to stuffiness. Anything higher could cause issues like mold growth or damage to the home as paint blisters. If you find yourself suffering from dry weather, adding a humidifier can be an easy way to add moisture to the home. Many humidifiers allow you to preset the machine to keep humidity levels within a certain range. However, if you have dust allergies or live in an already humid climate, a humidifier might not be a good solution.
- American Academy of Allergy, Asthma and Immunology. (2020). Humidifiers and Indoor Allergies. aaaai.org
- Anderson Air. How to Tell if the Air is Too Dry in Your House: Expert Tips. andersonair.com
- Biological Rhythm Research. (2011). Humidity and Sleep: A Review on Thermal Aspect. tandfonline.com
- Building and Environment. (2018). A Review of the Environmental Parameters Necessary for an Optimal Sleep Environment. sciencedirect.com
- Discovery. (2019). Here’s Why Static Shock is Worse in Winter. discovery.com
- Environ Res. Risk Effects of High and Low Relative Humidity on Allergic Rhinitis: Time Series Study. pubmed.ncbi.nlm.nih.gov
- International Journal of Biometeorology. (2005). Effect of Humid Heat Exposure in Later Sleep Segments on Sleep Stages and Body Temperature in Humans. springer.com
- International Journal of Hygiene and Environmental Health. (2018). Indoor Air Humidity, Air Quality, and Health – An Overview. sciencedirect.com
- Michigan State University. (2021). Animal Welfare at the Fair: Thermoregulation and Thermoneutral Zone. msu.edu
- National Asthma Council of Australia. (2016). Indoor Humidity and Your Family’s Health. nationalasthma.org.au
- National Library of Medicine. (2022). Humidifiers and Health. medlineplus.gov
- The New York Times. (2022). How Can I Stop Snoring? nytimes.com
- The Sleep Foundation. (2022). Humidity and Sleep. sleepfoundation.org
- The Sleep Foundation. (2023). Why Do People Snore? sleepfoundation.org
- U.S. Environmental Protection Agency. (2023). Moisture Control, Part of Indoor Air Quality Design Tools for Schools. epa.gov
- U.S. Environmental Protection Agency. (2023). Mold Course Chapter 2. epa.gov
- U.S. Environmental Protection Agency. (2023). What Does Mold Smell Like? epa.gov
- U.S. Environmental Protection Agency. (2023). What is the Difference Between Mold and Mildew? epa.gov
- University of Minnesota Extension. (2023). Do You Have Too Much Moisture in Your Home? extension.umn.edu
- University of Missouri Extension. (1998). How to Prevent and Remove Mildew – Home Methods. extension.missouri.edu