How do Humidifiers Work? Research Suggest they Have Benefits

Do you ever wake up with cracked lips, dry skin, or a sore throat during winter? If so, then you are experiencing low humidity.

Most people think it is the cold that causes these seasonal symptoms, but they result from low moisture in the air.

One of the best solutions for this is to use a humidifier. But before you get one, it is advisable to understand how do humidifiers work.

What does a Humidifier do?

Humidifiers add water into the atmosphere to bring a room or a building’s humidity level up to a bearable range for humans.

When humidity is low, people can begin to experience respiratory difficulties, dry skin, and even itchy eyes. It also intensifies the level of static electricity, increasing the number of shocks we feel when we touch metallic objects.

Why does this happen during winter?

From our elementary science, we know that there is water in the air. The amount of water air can hold depends on the temperature. When it is hot, the air can contain more water and very little when it is cold.

Relative humidity (RH) is the amount of water in the air compared to how much it can hold. The recommended level of humidity is between 30% – 50%.

The level of humidity determines how much sweat on our skin can evaporate. When the RH is at 100%, sweat doesn’t evaporate because the air is already saturated, making us feel hot and sticky.

During winter, low humidity makes all the sweat (moisture) evaporate from our skin, leaving us feeling cool and dry. In fact, we tend to feel colder depending on the level of humidity, even when the temperature is unchanged.

While there is very little we can do about humidity outdoors, we can certainly correct the level in our homes. 

How do Humidifiers Work?

There are different types of humidifiers, with each one working slightly differently. What is common is that they all have a container for carrying water. There is also a fan that will infuse the air with the water that is evaporated.

For greater detail, these are the different types of humidifiers.

Types of humidifiers

1. Steam Humidifiers

One of the simplest types of humidifiers is the steam version. It is also known as a vaporizer, and it does as you would imagine. A steam humidifier uses electricity to boil water before a small fan cools the evaporating water slightly as it is expelled into the room.

This is a small device and is very common because of its ease of use and low price-point. Another benefit of this design is that you can put medicated inhalants or essential oils to improve respiratory problems or make the room smell fragrant.

The downside of this type of humidifier is that the unit gets hot, making it unsafe for children and pets.

2. Evaporative humidifiers

Evaporative humidifiers or evaporators are the oldest and most common type of humidifiers. They are based on the ancient practice of humidifying by placing a bowl of water in a room so that the liquid can evaporate.

The modern, mechanized version has a wicking filter and a fan to speed up the process. It is a type of cool humidifier, so it is safer to be placed around children and pets.

Evaporators are also self-regulating, so the unit will reduce or increase the amount of water being added to the air depending on the RH.

3. Impeller humidifiers 

Another type of cool humidifier is an impeller. It uses a rotating disk revolving at high speed to turn water into droplets. These droplets are splashed against a diffuser that breaks it down even further, and the water rises into the room as mist.

Because of the simple technology, impellers are very affordable. They are also popular with families and pet owners. Their main downside is that they are pretty noisy.

While its basic tech is a financial blessing, it is also a curse. These units are capable of expelling bacteria in water without prejudice. It is, therefore, vital that the filter is changed regularly and the unit is cleaned often.

People with asthma and allergies are advised not to get this, as they can become dangerous when used too often.

4. Ultrasonic humidifiers 

An ultrasonic humidifier has a metal plate or diaphragm that produces ultrasonic vibrations, which break up water and cause it to rise as mist out of the unit. They function similarly to loudspeakers. Unlike speakers, however, they are virtually silent, making them great for light sleepers.

Just like impellers, these units can also release bacteria into the atmosphere. It is best to buy a unit that is antimicrobial and has a filter.

Ultrasonic humidifiers need to be cleaned regularly to prevent mold and bacteria growth. As they are easy to clean, this is not a problem.

5. Central Humidifier 

Finally, we come to the biggest type of humidifier. Central humidifiers are large units that are put in HVAC systems to humidify an entire house or building.

These are the most expensive type but are the only option if you want to humidify several rooms at once. They are also cool humidifiers.

Benefits of Using a Humidifier

Using a humidifier has several benefits for both people and houses.

As mentioned earlier, the most common benefit is that it prevents your skin from drying. While this is usually harmless and does nothing more than make you look pale, dry skin affects people differently. In some instances, dry skin may cause itching, redness, and cracks that bleed.

The same thing happens to our lips when they are too dry. If for some reason, lip balm isn’t enough to keep this at bay, then a humidifier will come in handy.

Besides these minor health risks, a humidifier can also help people that suffer nose bleeds, sinus congestion, head colds, dry throat, and dry cough during winter. For people that sing or speak to large crowds regularly, a humidifier can also help protect their vocal cords because it cleans the air around.

If you or someone in your home has asthma or allergies, a humidifier can make breathing easier. However, it may also cause damage if it is not appropriately maintained. We’ll go into more detail in the next section.

When it comes to your household, the main benefit of a humidifier is that it can lower your electricity bill. As the RH level increases, our bodies feel warmer than the actual temperature. Therefore, you can lower the heater setting when using a humidifier, thus reducing your energy consumption.

If you have hardwood floors, low humidity can cause them to dry quicker and crack, similar to how it affects the skin. Low RH also causes glue in furniture to dry, which will make it weaker over time and compromise its integrity. 

The last significant benefit of a humidifier is to control or decrease static electricity. Electrostatic discharges (ESD) can damage sensitive electrical devices causing them to function at a reduced capacity or stop working prematurely.

Risks Associated with Humidifiers

– Burns

The most common problem with humidifiers is burns. This is a problem that happens with steam humidifiers. However, due to their medicinal benefits (when infused with an inhalant or essential oils), they remain a common and often necessary option.

If you must have a warm mist humidifier, ensure you keep it out of the reach of children, other vulnerable people, and pets. It is best to put a cool-mist humidifier in kids’ rooms.

– Condensation buildup on walls

When too much moisture is released, condensation can build up on walls and other surfaces. Condensation is the result of warm moist air coming in contact with cold, drywalls. This leads to the growth and rapid spread of mold.

To prevent this, position the humidifier in a central location and buy one with an in-built humidistat. That way, it will automatically switch off when it reaches the recommended RH level.

– Unclean humidifiers cause sickness

Dirty water tanks and filters in humidifiers are a source of bacterial growth. They can also spread allergens, minerals, and microorganisms, thus compromising the health of people with respiratory problems.

Newer designs try to protect against these threats by inserting antimicrobials, ionic sticks, UV light, and other forms of disinfectants. However, units should still be cleaned regularly.

How to Maintain a Humidifier

Each type of humidifier is used differently, so it is important to read the manual before use. Using a humidifier the right way will prolong its life cycle, help you get more out of it, and prevent accidents such as burns, spills, and shocks.

Another important aspect when it comes to maintenance is cleanliness. While dirty humidifiers can be dangerous for people with asthma and allergies, they can also affect people without respiratory conditions.

Dirty humidifiers can cause inflammation in the lungs and cause flu-like symptoms. Even though impellers and ultrasonic humidifiers are the typical culprits, every type of humidifier should be cleaned regularly to reduce risks.

How to Keep a Humidifier Clean

Below are some of the ways to clean a humidifier

  1. Clean your humidifier every three days – no matter how advanced your system is at fighting germs, you should clean it at least every three days. Unplug the machine and clean the tank with chlorine bleach, a 3% hydrogen peroxide solution, or any other disinfectant the manufacturer recommends. This will get rid of mineral and film buildup in the tank.
  1. Change the water often – the last thing you want to see in your water tank is a layer of film or other mineral deposits. One way to prevent this is to change the water frequently. Most humidifiers run for a maximum of 18 hours, so the tank can be cleaned every day and topped up with fresh water.
  1. Use distilled or demineralized water – as much as the humidifier filter will help prevent the spread of minerals and microbial, it can’t do much when mineral levels are too high. Minerals breed bacteria, block the air passage and cause crusty deposits to form. Depending on where you live, it may be better to use distilled water instead of tap water.
  1. Change the filters as recommended – a dirty filter might be worse than no filter, so it is imperative to change it as often as the manufacturer says. When kept in optimal conditions (the humidifier is cleaned regularly), most filters can last for up to three months. Some wick filters can be cleaned, so they won’t need to be changed as often.
  1. Get a specialist to check your central humidifier – the good thing about central humidifiers is that they require less maintenance. However, they still need to be checked at least twice a year, depending on how often you use them and the type of water in your area. It is best to get the HVAC repairer to do so rather than DIY.
  1. Replace old humidifiers – when a humidifier begins to build up deposits that are difficult to clean, it is time to get a new one. If this happens before the warranty runs out, then that could save you some money. In either case, getting a new one will be much better for your health and is worth the investment.
  1. Store humidifiers properly – before you put away your humidifier for summer, ensure you drain and clean it thoroughly. When it is time to bring them back out, clean them again and replace the filters, cartridges, and other parts recommended by the manufacturer.

A final maintenance tip that isn’t really for the humidifier is to keep the surrounding area dry. When you notice any condensation buildup or the floor getting wet, switch off the humidifier. Wet floors might mean a leaking device, while condensation means you are using the humidifier too much or on a high setting.

Overusing the humidifier will cause it to wear out quickly.


Humidifiers are very effective at improving the RH levels, which positively affects human skin, lips, lungs, and respiratory health in general. They also protect furniture and hardwood floors from damage.

People with asthma and breathing conditions are required to speak to a doctor before getting a humidifier because when they are not used or cleaned properly, these devices can do more harm than good.

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Melanie Mavery is an aspiring HVAC technician who is fascinated by the trends and opportunities in the HVAC industry. She spends most of her day writing content on home improvement topics and outreaching to prospects.  She's always looking for ways to support HVACs!