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How to Clean Your Humidifier Properly


Bringing a shiny new household appliance home is always exciting — particularly if the device promises an end to your dry skin, sore throat, and inflamed nose. Approximately 10 million humidifiers are sold in the United States every year. Whether you bought a humidifier already or are just about to, the goals are simple: increased comfort and improved indoor air quality.


To achieve them, however, you need to do more than set your brand new humidifier up and turn it on. Without proper maintenance, humidifiers can easily become counterproductive, and even turn into low-key biological weapons that pollute your air instead of improving it. What do you need to know about keeping your humidifier clean, and your air safe?


What Are Humidifiers?


Humidifiers are appliances designed with the aim of increasing the relative humidity in a space — which means that they add water vapor to the air around you. Each type of humidifier does this in a slightly different way. Some humidifiers are portable, so they can be moved from one room to another fairly easily. Others, so-called central humidifiers or whole house humidifiers, connect to your HVAC system and add humidity to your whole property.


Not all humidifiers are equally good, however:


  • Steam vaporizers work by heating water to create steam, and a sub-category called warm mist humidifiers cool this steam before releasing it into the air. Evaporative humidifiers use a fan to release water vapor present on an absorbent material. Although some of these humidifiers feature tanks of standing water, many do not. The Environmental Protection Agency has found these types of humidifiers to be safest to use.
  • Ultrasonic humidifiers are portable in nature and vulnerable to the accumulation of pathogen-attracting minerals within their tanks. Cool mist humidifiers, also called impeller humidifiers, make use of rotating discs to transfer water vapor to the air. They, too, may accumulate  limescale. According to the Environmental Protection Agency, these humidifiers have the highest risk of dispersing bacteria and mold into the air. Although they tend to be more affordable, these humidifiers are not generally recommended.


Who Needs a Humidifier?


Many people purchase humidifiers during the winter, when the heating has dried the air in their home out, making them uncomfortable. Others decide to buy a humidifier because they have allergies, and they have heard that humidifiers can help alleviate symptoms like a runny nose, sinus pressure, a sore throat, and itchy, inflamed, eyes.


Before you decide to install a humidifier, it is important to consider whether you need one. A humidifier can help you if the relative humidity levels in your home are often too low — and that means below 30 percent. When your indoor air is too dry, a number of uncomfortable symptoms can follow, in addition to some more serious complications:


  • The symptoms associated with chronic respiratory conditions such as seasonal allergies and asthma can grow more severe, and acute conditions like common colds can also feel worse.
  • You may become more vulnerable to viral respiratory illnesses such as cold viruses and COVID-19.
  • You may suffer from uncomfortably dry and flaky skin. This is especially true if you already had a skin condition such as eczema or psoriasis.
  • You may have nosebleeds more frequently.
  • You will become dehydrated more easily, and will have to pay close attention to your water intake.


Installing and using a humidifier can combat these discomforts. However, that does not mean that a humidifier is the right solution for every household — when the air becomes too humid, that, too, has the potential to lead to health complications. Excessively humid air, meaning relative humidity levels of over 50 percent, carries different risks:


  • Dust mites thrive in high-humidity environments. These tiny arachnids are present in almost all homes, but if your humidifier causes the humidity in your home to become too high, they will flourish. A dust mite problem will trigger allergy symptoms in many people, including the symptoms you may have been trying to alleviate by using a humidifier; a sore throat, sneezing, headaches, and red and uncomfortable eyes.
  • Mold easily takes hold in the same humid conditions. Aside from causing characteristic allergy symptoms, very much like dust mites do, a mold infestation can potentially saddle you with even more severe health problems. Some mold species are toxic, while others can cause systemic infections. Mold may build up inside humidifiers as well as settling on walls and other surfaces, including in hidden spots.


You want the relative humidity levels in your home to fall within the ideal range of 30 to 50 percent — not below it, but also certainly not above it. That is why, before bringing a humidifier into your home, it is crucial to first purchase a humidity monitor to check whether the air within your most important rooms is truly too dry. If it is not, and the humidity range already falls between 30 and 50 percent, a humidifier will not help you. Even if your air is indeed too dry, it is important to choose a humidifier that has a humidistat. This “humidity thermostat” will make sure that your appliance switches off once it detects that your humidity levels have reached 50 percent.


What Are the Dangers of Not Cleaning Your Humidifier Often or Well Enough?


The Environmental Protection Agency has warned that humidifiers can — unless meticulously maintained — be turned into rather effective microorganism dispersal mechanisms. The types of humidifiers that feature tanks with standing water, from which water vapor is subsequently released into your indoor air, are especially risky in this regard. Both molds and bacteria may build up within the tanks, and these pathogens are then automatically released into your home and therewith your airways.


Using water with a high mineral content in your humidifier carries its own dangers. Although the Environmental Protection Agency has not determined this to be a universal threat to human health, research carried out on rodent subjects has shown that, when the minerals commonly found within tap water are dispersed into the air and inhaled, lung inflammation may follow. The minerals in your tap water, such as calcium and silica, are especially likely to cause irritation in already vulnerable people such as the elderly and those with chronic lung conditions.


In addition, the buildup of these minerals within your humidifier, in the form of limescale, provides an excellent breeding ground for germs.


Failing to clean your humidifier frequently enough can, then, lead to the accumulation of mold, bacteria, and minerals, all of which you and other members of your household are then forced to breathe in. Not cleaning your humidifier as often as you should is not the only danger, however — ironically, people who go above and beyond may face a different risk. So-called “humidifier disinfectants” have been associated with lung injury when traces of these cleaning agents find their way into your airways when you turn the appliance back on, and these specialized products are not recommended.


How Do You Clean and Maintain Your Humidifier Properly?


With so many different humidifier models on the market, each works slightly differently. It is, therefore, crucial to read the instruction manual carefully to find out how to safely take the appliance apart in order to clean it. The general steps you should take to use your humidifier responsibly are, meanwhile:


  • Using distilled water in your humidifier. Never choose tap water. Choosing “purified” water or using demineralization cartridges that the manufacturer of your humidifier may sell are alternative options, but distilled water is your best bet.
  • Cleaning your humidifier at least every three days, with many experts now recommending that humidifiers should be cleaned daily. This regular maintenance should include discarding the water, wiping down all the appliance’s surfaces (inside and out) with a clean towel or microfiber cloth while making sure to remove any grime or limescale, and refilling it with clean water.
  • Disinfect your humidifier at least once a week. The Environmental Protection Agency recommends following the manufacturer’s instructions or, where none are provided, doing so with a three percent hydrogen peroxide solution. After this process, it is crucial to rinse the appliance with water thoroughly multiple times, ensuring that none of the cleaning solution is present when you put the humidifier back into service.
  • Do not allow water to build up around your humidifier. Wipe any accumulation of moisture down as soon as you spot it.
  • Before putting your humidifier away when the winter is over, thoroughly clean and dry the appliance, removing cartridges or filters and making sure no water remains. Clean it again before you resume using it next season.


What Should You Do If You Have Not Been Cleaning Your Humidifier Properly?


It is easy to forget to clean your humidifier as often as you should — but if you are beginning to realize that you have not optimally maintained your humidifier, you may now be concerned about the possible consequences.


If you or anyone in your household has noticed respiratory symptoms like coughing, chest tightness, a sore throat, or breathing difficulties, and you suspect that your humidifier could have something to do with that, stop using the appliance immediately.


Have you, by any chance, spotted the presence of mold within your humidifier, or do you smell mold in your home? A mold infestation is among the more serious consequences of improper humidifier use, and it is important to take proactive steps as soon as possible to prevent long-term health complications.


MI&T can, as a seasoned nationwide mold inspection only company, assess the damage. We will look at your humidifier, but also carry out a thorough visual mold inspection of your entire property. Then, our independent mold inspector takes air samples that are lab-analyzed to tell you precisely what types of mold your humidifier may have been dispersing into the air. Equipped with our mold inspection report, you will know what you need to do to remediate your mold problem. That may begin with discarding your humidifier and, where required, replacing it with a safer model.