We tend to think about humidity at home as a definite negative, but did you know that too little can be as bad as too much? For people to stay in good health, we need relative humidity indoors at a certain level. Therefore, it’s a good idea to monitor the humidity levels at home. 
What causes humidity indoors? 
Relative humidity is the saturation of water vapor in the air. The amount of water vapor in the air can change depending on temperature. Higher temperatures can hold more water in the air, but lower temperature air can hold less water, which makes the water vapor condenses on colder surfaces. 
What humidity level is healthy for us and why? 
A human body needs a certain indoor level of humidity to stay healthy – namely between 30 and 50 percent.2 This is because too dry or too humid air each creates certain problems. When the air is too dry, people have dryer skin, irritated eyes and nasal passages, and conditions like eczema worsening. Also, low humidity can make it easier to catch airborne viruses since they are more likely to survive in cool and dry environments. 
Higher humidity comes with another set of serious problems triggering asthma and allergies – mold and dust mites. According to the Australian National Asthma Council, dust mites thrive in humidity levels of 70 percent and above at 20-25 degrees Celsius. Mold can get most active above 70 percent relative humidity as well but can start growing at 55 percent already. 
How to keep the air just right? 
To stay on top of the potential health hazards of too high or low humidity, the first step is to monitor it. Aranet4 air quality monitor offers not only CO2 measurements but also the humidity and temperature readings for keeping your house, office or other spaces healthy and comfortable. Use the monitor to see if you need to get the air drier or more humid.  
For drying the air: 
 – Try to find out where the excess moisture is coming from. Is it vapor from cooking or taking a shower that could be reduced by exhaust fans in the kitchen or bathroom? Are you air drying your clothes indoors and could you avoid that? 
 – If it comes to using a dehumidifier, clean and maintain the appliance well so it doesn’t become a source of biological pollutants.  
 – You could also consider if increasing ventilation or temperature would help.  
 – Since sources of excess moisture can vary, we suggest doing some extra research to pinpoint the problem before trying to fix it. 

If the air is too dry (lower than 30 %): 
 – Consider using a humidifier, but don’t go overboard – set it to turn off or turn it off yourself at 50 % relative humidity and make sure it sterilizes the mist it produces.  
 – You could also try air-drying clothes at home or leaving the bathroom door open when taking the shower. Start small though, as you don’t want it to get too humid or condensation to appear somewhere.  
 – If the air outdoors is more humid than indoors, it could be as simple as opening the windows.  
PRO Tips: 
If using any type of Heating, ventilation, and Air Conditioning systems, make sure you clean and maintain those in good condition. Otherwise, those could become a source of indoor air quality problems themselves.  




  1. United States Environmental protection Agency, What are the main ways to control moisture in your home?. https://www.epa.gov/mold/what-are-main-ways-control-moisture-your-home.
  2. United States Environmental protection Agency,  A brief guide to mold, moisture, and your home. https://www.epa.gov/sites/default/files/2016-10/documents/moldguide12.pdf.
  3. National Asthma Council Australia, Leanne Koster, Indoor humidity and your family’s health. https://www.nationalasthma.org.au/news/2016/indoor-humidity#:~:text=What%20is%20healthy%20humidity%3F,between%2030%20to%2050%20percent.

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