What Humidifiers Do: Types and Benefits


Humidifiers are devices designed to increase the moisture content in the air of indoor spaces. They play a vital role in maintaining optimal indoor humidity levels. Here’s a summary of what humidifiers do:

  • Add Moisture: Humidifiers release water vapor or mist into the air, raising the humidity levels in a room or building. This added moisture helps combat dryness in the air, especially during the colder months or in arid climates.
  • Improve Comfort: Proper humidity levels contribute to enhanced comfort and well-being. Humidifiers can alleviate common discomforts associated with dry air, such as dry skin, chapped lips, and irritated eyes and throat.
  • Respiratory Health: Humidifiers are often used to ease respiratory issues. The increased humidity can help soothe coughs, reduce congestion, and alleviate symptoms of conditions like asthma and allergies.
  • Sleep Quality: Maintaining a comfortable humidity level in bedrooms can improve sleep quality. It prevents dry throat and nasal passages, allowing for more restful sleep.
  • Protect Property: Adequate humidity levels can prevent damage to wooden furniture, flooring, and musical instruments, as overly dry conditions can cause cracking or warping.
  • Energy Efficiency: In colder months, properly humidified air can feel warmer, allowing you to lower your thermostat and potentially save on heating costs.
  • Reduced Static Electricity: Adding moisture to the air reduces static electricity buildup, making it more comfortable and safer, especially when using electronic devices.
  • Plant Health: Humidifiers benefit indoor plants by maintaining the necessary humidity levels for their growth and well-being.

What is the Ideal Indoor Humidity?

As I have mentioned, humidifiers are used to increase the humidity of the indoor air. So, how low is low humidity and what would be the ideal humidity in a house?

To start with, there is absolute humidity (which refers to the weight of moisture in the air) and there is relative humidity. In this case we are referring to relative humidity.

Relative humidity is the amount of water vapor in the air, out of the total amount that the air can hold at that specific temperature expressed as a percentage. Temperature therefore influences relative humidity levels (more on that later).

The ideal indoor relative humidity is 30% to 50%. The best humidity levels in winter is between 30% and 40% while the best humidity levels in summer is between 40% and 50%.

Therefore, if the relative humidity in your house is less than 30%, it means that the air is dry hence relative humidity is low. A humidifier can therefore be used to increase the relative humidity of your indoor air.

Humidifiers and Relative Humidity

Relative humidity is usually directly proportional to the temperature of the air. The higher the temperature the higher the relative humidity.

Warm/hot air has the potential to hold more moisture compared to cold air. That is the reason why relative humidity is high in summer but low in winter.

Apart from temperature/weather, location also influences relative humidity. For instance, despite Arizona being a hot state, the average humidity there is way lower compared to that of Alaska.

Usually, areas near water bodies like Florida have higher humidity than areas further away from the sea like Nevada.

In summer, folks in these humid states will most likely need a dehumidifier to remove the excess moisture from the air, thereby reducing the relative humidity. However, folks in arid areas will only need to run an air conditioner since the relative humidity is already low.

When winter kicks in, the cold air in these arid areas will hold even less moisture meaning that the air will be quite dry. And that is where humidifiers come in.

A humidifier will keep releasing moisture into the air until the relative humidity is within a comfortable range. As I mentioned, you need to measure the relative humidity levels in your house throughout the day to see if you need a humidifier.

Apart from a low relative humidity reading, how else can you tell that you need a humidifier? Let us look at that in more details.

Signs You Need a Humidifier

The following are the signs that you need a humidifier in your house. They can also be classified as signs and effects of low indoor humidity.

1. Dry/Itchy Skin

dry skin

A healthy skin will always have moisture in it. Also, there are tiny pores in a human skin which helps in perspiration (controlling body temperature through sweating). A good humidity levels ensures that our skin is not too dry or sticky.

If humidity is low, the air will be dry and it will pull moisture from the skin. The effect of that is that our skin will be left dry and itchy ( worse than the usual winter itch).

2. Dry and Irritated Eyes

Just like the skin, our eyes are always moist. The moisture in the eyes is vital to the overall health of the eye. Again, when the indoor air is dry, it will pull out moisture from our eyes leaving them dry.

Human eyes are covered by a thin membrane (the tear film) which helps to protect the cornea from microbial infections. When the tear film dries up due to low humidity, the eyes become easily irritated and more susceptible to infections.

3. Dehydration

The human body is 70% water. It is therefore natural that the body will lose water to the surrounding if it is surrounded by dry air for long periods of time.

If a part from having a dry and itchy skin you feel dehydrated, the relative humidity in your house is low and you may need to invest in a humidifier.

4. Nose Bleeding

Are you or a member of your family constantly nose bleeding especially during winter? That could be a sign that the air inside your house is dry. If you have a furnace, it will make the indoor air even drier which increases the likelihood of nose bleeding.

Your nose has a delicate tissue/lining called a nasal membrane. Low humidity causes this membrane to dry out and crack and therefore bleed especially when picked or blowing your nose.

5. Respiratory Infections

Many viruses will survive in dry air than in humid air. Apart from that, dry air causes virus particles to lose their mass due to evaporation therefore becoming lighter and more mobile. These particles therefore move with relative ease and are more likely to get to your respiratory system.

Low humidity will also cause the following:

  • Nasal congestion
  • Headaches
  • Dry/sore throat
  • Chapped lips
  • Dry cough

6. Static Electricity

Are you zapped when you touch objects in the house? That is usually caused by imbalance of positive and negative charges in the body which is caused by friction, separation or induction, otherwise known as static electricity.

So, why is static electricity more prevalent in dry air than humid/moist air? That is because moisture is a natural electricity conductor and will therefore act like an earth wire. Dry air however will not help the situation and that is why you should get a humidifier to increase the moisture level in the house.

7. Cracking Wood and Furniture

Again, dry air will pull moisture from wood and other wood products like furniture causing them to shrink and therefore crack. Books and artwork will also become brittle due to lose of moisture.

If you notice wood products in your house cracking (or even gaps developing between wooden floor planks) you need to increase your indoor humidity. A humidifier will definitely help.

Benefits of Humidifiers

The following are the benefits of humidifiers in a house:

  • Keeps the skin and hair hydrated – By adding moisture into the air, your skin and hair will no longer be dry but will instead stay hydrated and healthy.
  • Prevents respiratory infections – A humidifier will increase indoor humidity and as a result virus particles will not move freely in the air. Also, the nasal membrane will stay moist and thus preventing respiratory infections.
  •  Reduces snoring – humidifiers help lubricate the air passage in your system thereby reducing snoring.
  • Protects eyes – When relative humidity is at optimal levels, the tear film stay moist which is vital in nourishing the eye and protecting it from infections.
  • Prevents static electricity – humid air acts like an earth wire and will therefore conduct the electric charges to the ground.
  • Wood products last longer – When relative humidity of the indoor is as it should be, wood products, books and artwork will maintain their moisture levels thereby lasting longer.
  • Add warmth – Dry air makes you feel cold since it pulls moisture from the skin leaving you exposed to the elements. By increasing the moisture levels in the house, the air feels warmer.

Types of Humidifiers

So, what type of humidifier is right for you? Well, let us look at the different types of humidifiers so that you can easily decide which one is the best for you needs.

The following are the different types of humidifiers:

1. Warm Mist Humidifiers

Warm mist humidifiers use an internal heating element to heat water and produce vapor. The vapor is then cooled before being released into the air. They are also called vaporizers as we will see later.

There are people who add essential oils in the water used for warm-mist humidifiers but that is not recommended. Actually, adding essential oils and/or inhalants in the humidifier may damage it and void its warranty.

2. Cool Mist Humidifiers

Cool mist humidifiers use cold water to create a cool mist which is then released in the air. Since these humidifiers don’t heat the water to produce mist, they are safe for folks with children and pets as there is no risk of burns.

There are several types of coo-mist humidifiers which include:

  • Evaporative humidifiers
  • Impeller humidifiers
  • Ultrasonic humidifiers

3. Central Humidifiers

central humidifier

Central humidifiers, also known as whole-house humidifiers are built in your HVAC system to increase the humidity of your whole house. They are the largest in size and also the most expensive.

Unlike other humidifiers, central humidifiers need to be installed by a professional HVAC technician which also adds to their cost. They are however the best humidifiers if you want to increase the relative humidity of every inch of your house.

4. Portable Humidifiers

As their name suggests, portable humidifiers are small in size and can easily be moved from one room to another. They also don’t need to be professionally installed. You just plug them to a power outlet and you are good to go.

The output of portable humidifiers is limited and are therefore used to increase the humidity in only the room they are plugged in. They are however cheaper and easier to maintain than central humidifiers.

5. Evaporative Humidifiers

What happens when you leave a bowl of water out, especially in an area with dry air? As you guessed, the water will evaporate. That is how evaporative humidifiers work, only that they are designed to work more effectively.

Evaporative humidifiers contain a fan/blower, wick filter and a water reservoir at the bottom of the unit. The filter will naturally pull water from the reservoir meaning that it will always be moist.

When the fan comes on, it blows moisture out of the filter which is released into the air in form of a cool fog/mist.

6. Ultrasonic Humidifiers

Ultrasonic humidifiers produce mist by making an inbuilt diaphragm vibrate at an ultrasonic speed. The vibrations breaks down water particles into a tiny particles which are then released in the air as a stream of a cool mist.

Ultrasonic humidifiers are safe if you have kids and are also compact allowing them to fit in tiny spots.

7. Impeller Humidifiers

Impeller humidifiers use a rotating disc (at high speed) to break down water particles into tiny particles which are then released in the air. Because of their small size, the particles can easily remain suspended in the air.

Although impeller humidifiers are inexpensive, they are not common because they are inefficient and are also noisy.

8. Steam Humidifiers

Steam humidifiers are also known as vaporizers. These are the warm-mist humidifiers which increase humidity of the indoor air by first heating water until it vaporizes (turns to steam).

Steam humidifiers have an internal water reservoir and a heating element. The element heats the water and once steam is formed it is released in to the air as a warm mist. The steam is cooled before being released into the air.

Steam humidifiers are powerful humidifiers but care should be taken especially if you have kids and/or pets since they can burn.

Maintaining Humidifiers

Humidifiers are very helpful in increasing indoor humidity which makes your house comfortable to live in. However, they can make you sick if you don’t properly maintain them.

Poorly maintained humidifiers can easily become a breeding ground for mold and bacteria. Mold can make you sick and also cause bad smells in the house.

The following are the steps to take to clean/maintain you humidifier in proper working condition:

  • Use distilled water – water from faucets contains minerals which can be deposited inside the humidifier.
  • Regularly (daily if possible) change the water. Unplug the unit, dry its inside surfaces then refill it with distilled water before plugging it back.
  • Regularly clean the humidifier using bleach or hydrogen peroxide solution. Twice per week would be ideal.
  • Change the humidifier filter regularly – check the manufacturer on the frequency with which to change it.
  • When storing a humidifier, throw away used filter/cartridges then clean and dry it.

Wrap Up

And basically that is everything about humidifiers. I hope that by now you know if you need a humidifier in your house and the type that you need.