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Can a Humidifier Start a Fire or Explode?

Humidifiers rely on water to do their job and provide moisture to a room when the air is stale or dry. Since humidifiers run on electricity and essentially evaporate the water inside them, when they run dry, they can cause a fire or explode, right?

A humidifier can start a fire if it overheats, but it can’t explode. When humidifiers run dry, the motor continues to run, which can cause it to overheat, melt the plastic, and start a fire. Steam humidifiers are the most likely type to catch fire, while evaporative models pose the lowest risk.

The rest of this article will discuss this question in more detail. We’ll first give a quick and necessary overview of how humidifiers work, then dive into why a humidifier might overheat and cause a fire. Finally, we’ll talk about how to operate a humidifier safely.

Can a Humidifier Start a Fire or Explode

How Do Humidifiers Work?

Humidity is when there is a concentration of vaporized water in the air. The humidity of air affects how you feel and how comfortable you are in a room.

There are three main ways to measure humidity:

  • Relative Humidity – the present state of humidity in the air
  • Absolute Humidity – the water content in the air
  • Specific Humidity – the ratio of the water vapor mass as compared to the total air moisture

The most common type of humidifier (and the type you’re probably familiar with) is the evaporative humidifier. This type of humidifier is very simple to use, and it is self-regulating.

Evaporative humidifiers have a reservoir that holds the water and dispenses it into a basin. A filter called a wicking filter will absorb the water, and a fan blows the air through the filter.

While the air blows through the filter, it will evaporate the water into the air. The air will then become more humid, which is great for reducing dryness and congestion.

Why a Humidifier Might Overheat

An evaporative humidifier is the least likely to overheat as it does not use heat in its dispersion mechanism.

However, when the water runs dry, it will start to smell and produce dry air.

If an evaporative humidifier runs on an empty water tank for too long, there is a slight risk that the motor could catch fire. However, this is extremely unlikely to happen.

Can a Humidifier Start a Fire or Explode?

Steam humidifiers, on the other hand, are more likely to start a fire. If a steam humidifier runs out of water, the intense heat used to boil the water may cause the humidifier to catch fire.

Almost every steam humidifier has an automatic shutoff mechanism that turns the machine off when the water runs out, so this shouldn’t be an issue. However, there have been instances in which this mechanism has failed and caused a fire to break out.

Can a Humidifier Start a Fire or Explode?

How to Use a Humidifier Safely

Humidifiers are considered pretty safe devices, but there are still a few precautions you should take to minimize your risk of health problems, home damage, or fire.

Use Distilled or Filtered Water

Your tap water may have unhealthy minerals

Using distilled or filtered water helps to minimize these unhealthy minerals as it is water that is already cleared of these minerals. When comparing distilled water to tap water, it is significantly healthier.

Clean the Humidifier Frequently

Every time you use your humidifier, you should clean it. Make sure to clean and completely dry the water tank. You also want to rinse the filter.

It is best to clean your humidifier using either vinegar or peroxide, which will kill any bacteria or mold that has built up. 

To prevent the buildup of bacteria and algae (and the unpleasant odors that come with them), you should use a humidifier water treatment solution each time you refill the water tank.

I recommend the BestAir Humidifier Bacteriostatic Water Treatment (available on Amazon). It’s non-toxic, affordable, and eliminates bacteria and algae before they grow to an unmanageable level.

BestAir Original BT Humidifier Bacteriostatic Water Treatment Solution

Place on a Flat Surface

When choosing where to place your humidifier, you want to ensure that it is flat and stable.

A humidifier that is stable is much less likely to tip over and spill water everywhere. It will also protect young children or small pets from knocking it over and getting hurt.

Can a Humidifier Start a Fire or Explode?

Change the Filters

The manufacturer is going to have instructions on how often to change the filters in the humidifier.

Always pay attention to these instructions to prevent any mold or mildew being released into the air and causing severe health problems.

Keep the Humidifier Away from Heat Sources

Since humidifiers are most likely to be used in the dry and cold months of winter, there is most likely going to be some heat source operating near the device.

Make sure to keep the humidifier away from these heat sources. It is especially important to keep away from space heaters, fireplaces, and heat vents that run hot, as this will significantly decrease your risk of fire.


  • Vincent Steele

    Vincent is a freelance writer based in Santa Ana, California. When he isn't writing articles for Temperature Master, he can be found biking or hanging out with his cat, Shelly.

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