What Fan Speed For A Dehumidifier?

A dehumidifier is a worthwhile investment to help prevent the buildup of mildew and mold in any building.

Too much humidity can cause avoidable health hazards, making it vital to ensure that your dehumidifier fan speed settings are configured properly, along with other settings.

The highest fan speeds possible should be used at high humidity to help bring the humidity down to a more acceptable level. Once the humidity has been brought down, lower fan speeds can be used to keep the humidity level stable and to save energy.

While there are many types of dehumidifiers out on the market, a common factor for all brands are the fan speeds.

Our dehumidifier has three fan speeds: sleep, normal and turbo.

Which one we use can depend on how the target humidity level we set compares to the current humidity of the room. The dehumidifier will also automatically switch between these fan speeds on certain modes.

Dehumidifier Fan Speed Control
The button on our dehumidifier that we can use to change fan speeds

Figuring out what dehumidifier fan speed is the best for your personal needs and how to use it can be slightly confusing. Read on to learn more about dehumidifier fan speeds and which spaces will benefit from one.

Dehumidifier Fan Speeds

Because different inside spaces will have different levels of humidity depending on their function, each room a dehumidifier is placed in might need to use a different fan speed.

For example, a bathroom will usually be exposed to more humidity than a bedroom, so putting a dehumidifier in a bathroom at a higher fan speed is usually more necessary.

Energystar.gov considers a small to medium room to be less than 2,000 square feet. They consider a larger room to be greater than 2,000 square feet. This classification is for residential buildings such as homes.

To start, if you are in a bigger residential space, it can be best to set the dehumidifier on high fan speed until the humidity goes down.

Depending on your dehumidifier, the device will have different levels of fan speeds.

Some dehumidifiers will only have 2 and others will have 3. These are the 3 standard fan speeds on a dehumidifier:

  • Low
  • Medium
  • High

Low Fan Speed

A low fan speed uses the least amount of energy and moves the slowest.

The low fan speed on our dehumidifier is referred to as ‘Sleep’.

Low fan speed is ideal for saving energy but will reduce performance

The owner’s manual states for Sleep fan speed:

‘Low fan speed, eco dehumidifying and heating modes.’


Medium Fan Speed

A medium fan speed uses more fan speed and moves a little more than the low fan speed setting.

The medium fan speed on our dehumidifier is referred to simply as ‘Normal’.

Medium fan speed offers a compromise between performance and energy usage

The owner’s manual states for Normal fan speed:

Middle fan speed, eco dehumidifying and heating modes.’


High Fan Speed

The high fan speed uses the most amount of energy and moves the fastest. You should use the highest setting if the room is extremely humid and need to get the humidity level down as quickly as possible.

High fan speed is referred to on our dehumidifier as ‘Turbo’.

High fan speed means high performance but higher energy usage

Our owner’s manual states for this Turbo fan speed:

High fan speed, maximum heating, provides maximum dehumidifying and heating performance.’


Does Fan Speed Matter On A Dehumidifier?

Fan speed matters a lot with dehumidifiers.

The higher the fan speed is, the more energy it uses and the faster it will work to lower the humidity level.

Once the humidity is at a comfortable level, you can turn the dehumidifier down. By doing so, the air humidity is stabilized and you will save on energy costs.

While the U.S. Department of Energy (or the DOE) required home dehumidifier manufacturers to follow the new energy standards in 2007, that does not mean that running your dehumidifier at high speeds all day will not raise your electric bill.

It’s important to be conscious how long you run your dehumidifier.

Our dehumidifier has a ‘Smart’ mode where it will automatically adjust the fan speed based on the current humidity level.

Dehumidifier Mode Control
Our dehumidifier in Smart mode, which automatically regulates fan speed

‘In smart mode the target humidity is set to 50% and the dehumidifier will automatically determine the best fan speed and dehumidification rate according to the humidity of the room. The fan speed cannot be changed manually.’


When To Turn On A Dehumidifier Fan

Too high of a humidity can be harmful to humans and the homes we live in. It can cause health issues and damage a building’s structural elements over time. These effects might be slow or sudden.

Here are some things to look out for if you think your home may have a problem in regards to excess humidity:

  • A musty smell
  • Mold
  • Mildew
  • Vermin such as cockroaches
  • Condensation on walls, windows, and furniture
  • Wood starts to warp and bend
  • Your own body sweating

If you notice any of these signs, then you should be sure to lower the humidity in the building right away.

The easiest way to do this is by using a dehumidifier on max settings (include fan speed) until humidity comes down to acceptable levels.

How Much Humidity Is Too Much Humidity?

30% to 50% is considered the best humidity range for air quality.

This range is the most comfortable for humans to breathe in. It also limits bacteria growth as bacteria love wet spaces. More than that is considered too humid and less than that is considered to be too dry.

If the temperature is cold outside, 30% to 40% is the ideal comfort level.

Setting our dehumidifier to 40% target humidity

Energy Star has a classification for humidity levels over 50%. These categories scale how bad the humidity is in three levels:

  • 50% to 75% is a little to moderately damp
  • 75% to 90% is very damp
  • 90% to 100% is wet

If the humidity level is over 50%, mildew, mold, and bacteria will eventually thrive.

Spaces To Use A Dehumidifier Fan

Humidity can accumulate anywhere and in any type of building, especially the home. The home is one space where a lot of people spend a majority of their time.

Some common residential rooms you might find dehumidifiers are:

  • Bedrooms
  • Living rooms
  • Basements
  • Crawl spaces
  • Laundry rooms
  • Attics
  • Bathrooms

These are all rooms that are vulnerable to increased humidity.

Whether you live in a drier region, such as Arizona, or a wetter area, such as Florida, bathrooms and laundry rooms are especially likely to become humid. When you shower or simply hang your laundry up to dry, these actions cause condensation to accumulate.

Dehumidifiers are used in commercial buildings as well. They might even be in types of places you do not expect. Examples of commercial buildings are as follows:

  • Ice rinks
  • Swimming pools
  • Office buildings
  • Industrial buildings
  • Manufacturing plants
  • Warehouses

These are all types of buildings that can become extremely humid. Indoor swimming pools are especially vulnerable to humidity due to both the heat and the water evaporating from the pool.

Fan Speeds In The Home

A dehumidifier’s fan should be set to a higher speed when using it in bathrooms and laundry rooms.

Once the Relative Humidity (RH) reaches a comfortable 30% to 50%, turn the fan speed down to keep the RH level stable.

To save more energy, it’s also possible to turn the dehumidifier off until the humidity rises again.

In rooms that are not exposed to as much humidity, such as bedrooms or living rooms, you can keep the fan speed at lower levels.

If there’s a high percentage of humidity in those rooms, put the fan on high until the humidity goes down. This will keep your electric bill lower than it would have been if you consistently kept the fan speed on high.

Attics typically have low humidity levels, so a dehumidifier would not be useful when placed in these parts of your home.


The proper fan speed for a dehumidifier really depends on the size of the space you are trying to dehumidify.

At first, the fan speed should be set to high then lowered once the humidity level in the room is around 30% to 50%.

This will save both energy for the environment and keep any utility bills reasonably low.

The longer the fan runs at high speed, the more energy it will use. By dehumidifying a house or any other commercial building, you can save money in the long run.

It’s cheaper to keep a building dehumidified than it is to have to rip everything apart because there is black mold all over the walls, ceilings, and floors or fix whatever the humidity destroyed.

Further Reading

What The Numbers On A Dehumidifier Mean

The Best Time Of Day To Use A Dehumidifier

What Should I Set My Dehumidifier At?

When Should I Turn Off My Dehumidifier?

What Are The Settings On A Dehumidifier?