Do Electric Fan Heaters Dry The Air? (Yes And No)

Many people will tell you that electric fan heaters dry the air in a room. That is their honest perception through uncomfortable experiences of itching eyes and dry tongues.

It’s not technically true that these appliances dry out the air by removing moisture from the air. However, it’s definitely true that it can feel that way.

This article explains what’s going on in plain English. And we’ll give you plenty of tips on how to prevent that uncomfortable dry air feeling.

Do Electric fan heaters Dry The Air?

Let’s walk through what happens when you run your fan heater. Of course, it warms up the air nearby.

As the air temperature increases, the capacity of that air to retain moisture also increases. In other words, warm air can hold more moisture than cold air.

Some heating appliances add moisture as well as heat to the room. Gas heaters do so. But your electric fan heater doesn’t add moisture to the air.

So, your fan heater has warmed the air but hasn’t added any extra moisture to it.

But we’ve said that warmed air can hold more moisture than when it was cold. That’s the important point to understand.

The key to why you feel that the air is drier is that the “relative humidity” has dropped. If you’re not sure what that means, then we’ll explain it now in really simple terms.

Dry the airr

Relative humidity

Relative humidity is the amount of moisture in a room divided by how much moisture the air could hold at its current temperature.

Here’s the simple equation:

When your fan heater warms the air, it has increased the air’s capacity to hold moisture.

However, the amount of moisture remains the same.

Basically, you increased the bottom part of the equation while leaving the top of the equation unchanged.

That means that the overall relative humidity has decreased. And the decreasing amount of relative humidity is what we experience as dryness in the room.

Why Falling Relative Humidity Feels Like Dryer Air

Because the warm air can hold more moisture, it wicks moisture from your exposed body parts more quickly.

The moisture evaporates from your skin, eyes, mouth, and sinuses and is held in the surrounding air.

As we said, the overall moisture in the room hasn’t been reduced. But your body moisture has transferred into the air around you.

You feel your skin getting drier which can eventually feel like itching. Your mouth gets drier which can make your tongue stick uncomfortably to the roof.

Your throat gets drier which can move from an irritating tickle to an itch.

Your nasal passages and sinuses get drier which can lead to headaches.  

The solution isn’t to throw out your fan heater! Our next section gives you plenty of tips.

Tips On Preventing Dryness In A Room

Remember the equation in the previous section where we pointed out that the top half had stayed the same? That was the moisture level in the room.

Your electric fan heaters do not add moisture but you can do so in another way. One way to do so is to purchase a humidifier to offset the fan heater.

However, that isn’t usually necessary. There are other solutions that shouldn’t cost you anything. Some will be more suitable than others, depending on your accommodation.

Household plants

The trick here is to add plenty of potted plants around the room and keep them well-watered. Some of that water transfers into moisture in the air.

The best choices are plants with wide leaves.

A More Technical Explanation Of Relative Humidity

Spray bottle

A simple plastic spray bottle is a lot cheaper than a humidifier. By spraying water droplets around the room every hour or so, you should mitigate the dry air experience.

Of course, this is an active solution. If you’re feeling a little lazy, try the next tip.

Damp sponge

Don’t want the hard work of watering plants or spraying the air. This one is for you.

The solution is to wet a sponge, put it into a bowl, and place the bowl in a corner.

The heat will slowly evaporate moisture from the sponge.

Drying your clothes

If you’re like me, you sometimes hang wet clothes on a rack to dry them at a safe distance from a radiator.

This actually helps with increasing the moisture in the room.

Drying your clothes

Warming a pot of water in the room

Warming a pot of water will ensure that some moisture evaporates into the air.

You can do this by placing a pot of water on a heated radiator. Of course, if your only source of heat is the electric fan heater, this isn’t feasible.

The alternative method is to place a pan of water by a window that receives sunlight. Again, the evaporating moisture alleviates the relative humidity problem.

Are you rolling your eyes and thinking that you haven’t seen the sun in weeks? That’s why I put this one near the end.

A More Technical Explanation Of Relative Humidity

Relative Humidity was the only technical term I used in the plain-English explanation of why the room feels drier.

I omitted a few other terms to avoid getting too complicated. Here, I’ll give a more complex explanation.

The absolute humidity is the amount of moisture in the air, while the relative humidity is this quantity divided by the capacity of the air to hold moisture.

The rate of evaporation measures how fast the moisture vaporizes, which of course is dependent on the room temperature.

The rate of condensation measures the reverse of evaporation. Think of water appearing on your windowpane. This rate depends on other factors such as air pressure.

Relative humidity is the rate of condensation divided by the rate of evaporation…times one hundred.

RH = condensation rate / evaporation rate * 100

Penn State

Low relative humidity means that the evaporation rate is considerably higher than the condensation rate.

Dean Casey
About Dean Casey

Hi, I'm Dean Casey, the founder and chief editor of

With over 15 years of experience in the HVAC industry, my passion is helping homeowners achieve optimal comfort and energy efficiency in their living spaces. As a certified HVAC technician and consultant, I have developed a deep understanding of home heating systems, insulation, and energy-saving practices.

I started this blog to provide well-researched, practical advice to homeowners looking to improve their home's heating performance and reduce energy bills. Whether it's comprehensive guides, hands-on product reviews, or expert tips, my goal is to share valuable information with you, my readers.

I enjoy spending time with my family and exploring the great outdoors when I'm not busy writing and researching. I'm also an avid DIYer, always eager to tackle new home improvement projects and share my experiences with you.

If you have any questions or comments about home heating, please don't hesitate to reach out through the contact page on the website. I'm always happy to help!

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