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Does A Humidifier Cool The Air In A Room?

If you live in an area where the air gets dry, you will know how essential a humidifier is. Not only does it keep dry skin and chapped lips at bay, but it also has some health benefits.

For people who live in a cold area, however, you may worry that putting the humidifier on to add moisture to the air might also drop the (already) frigid temperature. But does a humidifier actually cool the air in a room?

Cool mist humidifiers cool a room slightly but the added moisture makes it feel warmer. Low humidity causes moisture to evaporate from your skin making you feel cooler. Higher humidity levels slow moisture evaporation helping to retain body heat. Vaporizer humidifiers produce steam and warm the air.

While you may think it should be the other way around, adding moisture to the air will make it feel warmer. Air holds a certain amount of water. Higher moisture levels in the air will help you feel more comfortable.

In this article, we look at how humidifiers change the temperature feel in a room. Keep reading for information on how this works and why humidifiers are important for temperature control in a room.

Does A Humidifier Cool The Air In A Room?

How much moisture air holds depends on its temperature. When the temperature outside drops sharply, the air loses moisture and cannot regain it until the air is warmed up again. 

In many cases, this same cold air that has lost a lot of its moisture is then heated indoors, but no new moisture has been added to it. This makes the air warm but also very dry. Not only is this usually uncomfortable for most people, but it also makes you feel colder.

When an impeller or ultrasonic humidifier is turned on in a room, the water evaporates into the air to increase the humidity. Still, the water droplets produced by the humidifier require heat to evaporate. Evaporation happens by removing heat from the air around the humidifier.

Because of this evaporation, the temperature will drop slightly in a room. This works similarly to how water misters can drop the ambient temperature on a patio or porch in hot months.

However, the drop is only slight and, in many cases, won’t be felt immediately unless you place your hand in the mist. Also, if there is a heat source in the room, this is often producing more heat than the humidifier is removing, and so the net effect is still a warmer room.

When a vaporizer humidifier is used, it will raise the temperature as warm steam is pushed into the air in the room. Again, this will usually only be a small increase.

Why Does It Feel Warmer In A Humidified Room?

Even though a humidifier cools the room very slightly, people often say it feels warmer in the room as soon as the humidity begins to climb.

The reason for this is that the moisture content in the air affects how comfortable it feels for people. Low humidity dries out your skin and lungs and makes a room uncomfortable to be in. 

The amount of moisture air can hold depends on its temperature. Warmer air can hold more moisture. This means that cold air with very little water vapor in it, which is heated, can accept more moisture immediately.

Cold air (e.g., 68⁰F) can only hold about 0.63oz of water. Warm air (e.g., 77⁰F) can hold about 0.78oz of water. If the temperature of the air climbs to 77⁰F but only contains 0.39oz of water, then the relative humidity of that air is only 50 percent. The air can still easily accept moisture.

If you are in a warm but dry room, your skin sweats because of the warmth, but because the air is dry, it immediately evaporates, which cools your skin. This makes you feel colder even though the temperature has been raised.

A room with higher moisture levels will not evaporate moisture from your skin as readily, allowing your skin to retain its heat rather than the cooling effect of moisture evaporating from your skin. You will feel warmer even though the room temperature has not been raised, only the humidity of the air.

We are most comfortable when the relative humidity is about 45 percent. This humidity level ‘feels about right’ for the temperature and for what your body senses the temperature should be. Your skin, throat and lungs don’t dry out.

Do Different Types Of Humidifiers Cool The Air More?

There are three main types of humidifiers:

  1. Vaporizers, or steam, humidifiers heat water using an element and push this moisture into the air.
  2. Impeller and ultrasonic humidifiers agitate the water to the point that small droplets are released into the air as a cool mist.
  3. Wick humidifiers pull water from a reservoir and use a fan to evaporate it into the air.

Because each of these humidifiers delivers moisture into the air in a slightly different way, they can cool or heat the air.

A vaporizer humidifier uses the heat of the steam to cause it to rise into the air. As this is hot steam, it can raise the temperature of the air rather than cool it.

Impeller and ultrasonic humidifiers produce air with a high content of heavy water droplets. Often as this air comes out of the spout, it will immediately settle to the ground. In the same way that a water mister cools the air on a patio or porch, as the water droplets descend, they cool the air around the mist as it evaporates into the air. The coolest air is felt at ground level, where the vapor descends.

Wick humidifiers also cool the air, but because the evaporation of the water is happening inside the humidifier rather than in the air around the humidifier, it can often feel less cool than impellers and ultrasonic humidifiers.

What Are The Benefits Of A Humidifier In A Room?

Not only do humidifiers make a room feel warmer, there are a number of other benefits to running a humidifier in a room:

  1. Improved health
  2. Healthy plants
  3. Energy cost savings 

Here is how each of these are beneficial.

Improved Health From A Humidifier

Humidifiers help to make a home less conducive to germs and fungus. Airborne viruses often thrive in dry air, and raising the moisture level with a humidifier in a room can help to reduce the abundance of germs.

Happier Plants In Humid Rooms

Most plant care experts will tell you that because many indoor plants come from tropical climates, they fare better in humid rooms. Keeping the humidity in a room around 45 percent will keep your indoor plants happy.

Improved Energy Use Because Of Humidifiers

Because a room with higher humidity feels warmer, it may stop you from increasing the temperature in a room or keeping the radiator on for longer. Adding some moisture to the air can significantly change the amount of energy used to heat a room. 

Of course, seasonal comfort is the obvious and unspoken benefit of a room with higher humidity. Not only does the amount of static in the air reduce, but nose irritation and dry skin are less obvious.

A room with higher humidity will feel more like other seasons in the year, slowing down that feeling of a sharp change in season.

Are There Any Dangers When Using A Humidifier?

Note the following when using humidifiers regularly:

  1. Because vaporizer humidifiers produce hot steam, they can scald if you let your skin stay in the steam for too long. Especially for young children and pets, this can be dangerous.
  2. Impeller and ultrasonic humidifiers may harbor bacteria if not cleaned regularly. These bacteria are then pushed into the air with water droplets and can cause breathing problems and mold. Always clean humidifiers regularly and replace water at least every 3-4 days. Where possible, use purified water.

While not a danger, all types of room humidifiers make a small amount of noise. Depending on your tolerance for background noise, this can become irritating. Ultrasonic humidifiers make the least noise, so consider this when choosing a humidifier.


Air humidifiers can make a room slightly warmer or cooler depending on the type of humidifier. The overall effect is a feeling of warmth, though. Because warm and dry air causes your skin to sweat and then evaporate, that sweat makes you feel cooler.

A room with higher humidity will slow this evaporation off your skin and make you feel warmer even though the temperature has not changed. This can not only make you feel more comfortable in a room, but it will also reduce heating costs and keep all your plants happy.

If you are concerned that a humidifier will cool a room, don’t. You will be grateful for the increased feeling of warmth!