dehumidifier not lowering humidity

Dehumidifier not lowering humidity is a tricky situation to deal with. You know there is an issue somewhere but you cannot seem to point it out.

You will quickly notice your dehumidifier underperforming if humidity levels are generally high in your area and only come down with a dehumidifier.

But, you may ask, “Why is my dehumidifier not lowering humidity?” Well, it could be due to many reasons.

Dehumidifier not lower humidity could be due to a faulty fan or bad coils, but it could be due to your large room or a constant source of humidity in the room. 

The Surprise of Dehumidifier Not Working

the surprise of dehumidifier not working

Imagine this: You rise early and ready yourself for the day. It is a wet day, so you switch on the dehumidifier before heading to the kitchen to make some coffee.

You finish off your errands and come back to your room, only to find that the humidity is still over the roof.

How is that possible if you have had the dehumidifier going since you got up?

Several explanations exist for this phenomenon. From the broken fan to the defective coils inside. Anything you can think of might play a role.

Fact: The first dehumidifier was invented by Willis Carrier, an American inventor, in 1902. 

How Does a Humidifier Work?

how does a humidifier work

To understand what might go wrong, you must learn how those dehumidifiers work.

Most dehumidifiers use a refrigeration system to extract air from the space and pass it over a coil cooled to a low temperature.

Refrigeration dehumidifiers are a typical name for these devices.

The moisture condenses on the cold surface, and the water trickles down into the catch basin. 

But, other dehumidifiers are also available. For instance, desiccant dehumidifiers are a popular alternative to the traditional evaporative cooling method.

These dehumidifiers work by circulating air over a desiccant-coated wheel. 

Desiccant is dried and regenerated by passing warm air through it, which removes the water and prepares it for another round of moisture collection.

It has a water collection tank that stores the gathered liquid. 

How Long Does a Humidifier Take to Work?

humidifier work time

If there are no special damp issues and the room the dehumidifier is in is large enough, it might take a few days to a week for the humidity to drop to the desired level.

If the room has been flooded, this timeline does not apply, and one or more dehumidifiers, air movers, and other specialized equipment will be required.

Experts in water damage restoration typically handle these tasks.

Fact: By maintaining the right humidity levels, dehumidifiers can work amazingly well to improve the lifespan of your furniture. 

Dehumidifier Not Lowering Humidity?

dehumidifier fails to reduce humidity

While dehumidifiers may take a while to show results, you should notice some improvement in the air quality soon after you turn a dehumidifier on.

But, if it does nothing to lower humidity, you may have an issue. 

A Faulty Fan

When your dehumidifier misbehaves, you may always want to start by inspecting the fan.

From the outside, your unit may appear to be functioning normally.

But, if you do not have the fan working correctly, your dehumidifier will not be able to draw in air.

You might think everything is fine if you just look at the lights and listen to the noises coming from the appliance.

A problem could be as minor as a faulty fan motor or as obvious as bent or cracked blades.

Fact: Rock salt is a natural dehumidifier and may help when your dehumidifier is not functioning properly. 

Fixing a Faulty Fan

fixing a faulty fan

To fix the issue, you have to access the internal parts of your dehumidifier. It should not be that tricky.

Although there will be some variation from model to model, the general procedure should be the same:

  • Wait a few minutes after carefully turning off your dehumidifier.
  • Take off the filter and front plastic panel and unscrew the cover plate.

After that, you may remove the cover and gain easy access to the fan’s motor and bearing.

  • Check the blades for signs of bending or tearing.
  • Use a multimeter to ensure the motor is running smoothly.

If you detect any damage or malfunction, you will need to replace the broken part.

There are a ton of how-to videos you can watch online if you are a visual learner. 

A Bad Coil

a bad coil

Just like a faulty fan, a bad coil can also make your dehumidifier stop working effectively.

Since your coils are not moving parts, this can be a little more difficult to detect than a broken fan.

In case you are unfamiliar with the function of these parts, it truly helps to learn more about them first.

Every dehumidifier has two coils: one for hot air and one for cold air.

While the former warms the air and sends a current of drier air back into your room, the latter condenses the surplus moisture in the air that the fan has drawn in.

If either of these coils is unclean or broken, your appliance may give the appearance of functioning, but will not actually remove excess moisture from the air.

Fact: Ignoring your coils can lead to a loss in their ability to remove moisture from the air, which can lead to serious problems like leakage and overheating. 

Fixing Bad Coils

fixing bad coils

If you think bad coils might be the case, you must immediately cease all use of the dehumidifier.

The answer is to clean the coils in the same way that you access the fan.  

When you find your coils, wipe them off with a moist cloth to eliminate any debris.

This should get them back to regular operation and have your device dehumidifying once again. 

A Large Room

Sometimes, your dehumidifier is just not enough to handle a very large room.

It means you may need to invest in more dehumidifying equipment for your house to get better results.

As you probably already know, different models of dehumidifiers are suitable for different room sizes to effectively remove excess moisture from the air.

a large room

For instance, you are asking for trouble if you try to dry out your massive living room with a model not made for such a task.

Reducing humidity with an appliance made for a smaller room will be less effective in a larger room, but it should still function.

If you use a moisture meter and see that the percentage has not changed, the issue is not the size of the space, but rather the unit itself.

Resolving the Issue

A dehumidifier or those absorbent pellets commonly seen in hardware stores could be the answer, but only if you detect a significant drop in humidity levels.

The pellet solution will be significantly less expensive initially, but will require constant upkeep due to their limited lifespan. 

High Humidity Source

high humidity source

If there is a constant source of high humidity, a dehumidifier may not be able to successfully reduce the humidity level in the room.

In order to get the most out of your dehumidifier, you need to find out what is causing the excess moisture in the first place.

If there is a leak in the room, whether it is a plumbing line or the roof, the dehumidifier will not be able to keep up with the constant supply of moisture.

The same is true for external sources of moisture that leak into the room, such as leaking windows or walls, which can lead to uncomfortable levels of humidity. 

Resolving the Issue

Fixing the leak or upgrading the room’s insulation are two examples of managing high humidity sources.

Taking these steps can ease the burden on the dehumidifier and keep humidity levels down.   

Clogged Filters

clogged filters

Reduced efficiency due to blocked or dirty filters is a common problem with dehumidifiers.

As time passes, the filters become clogged with dust, debris, and other particles, lowering the dehumidifier’s efficiency. 

Resolving the Issue

To keep the filters unclogged and functioning properly, routine maintenance is essential.

You should refer to the manual to find out how to clean or change the filters properly.

You can keep the dehumidifier working well and reduce the humidity in the room by maintaining the filters on a regular basis


Dehumidifiers not lowering humidity is a cause for concern. Sometimes, your room is a bit too large for your dehumidifier to handle the humidity effectively.

But, even in that case, it will bring some change and lower humidity to some extent.

If there is no change in the humidity levels and your dehumidifier seems to be working, it could be due to a faulty fan, bad coils, or even clogged filters.