Dehumidifier Icing Up? Here are 4 Common Causes and Fixes

Josh Mitchell

Written By

Josh Mitchell

Expert Reviewed By

Holly Curell

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One of my friends had a serious humidity problem in her garage and she asked me to take a look at why her dehumidifier wasn’t solving the problem.

I checked on it and noticed an ice build-up on the front, and when I asked her about it she said she didn’t even realize that ice was a problem!

She couldn’t have been more wrong.

An ice build-up will stop the dehumidifier from working properly, and if you don’t fix the issue quickly, it can cause serious damage to the appliance.

The good news is that you can often fix a frozen dehumidifier, but you need to know what the problem is.

In this guide, I’ll explain why your dehumidifier is freezing up and show you how to quickly solve the issue.

Key Takeaways

  • The most common cause of dehumidifier icing up is a room temperature below 60 degrees Fahrenheit. Move your dehumidifier to a warmer room to remedy this issue quickly.
  • More serious issues that can cause icing include blocked air flow, faulty fan or faulty sensors. This can also be a telltale sign of a dirty and not well maintained unit.
  • Turn the dehumidifier off when it ices up for at least 12-24 hours. Avoid using it in winters and try running it in short cycles. 

4 Reasons Dehumidifiers Freeze Up (And How To Fix The Issue)

For my friend, it was just because her garage was too cold so all we had to do was install a heater.

However, there are a few different reasons why a dehumidifier freezes up.

When we talk about a dehumidifier icing over, we aren’t talking about the whole device suddenly becoming frozen.

It usually starts with just the dehumidifier coils, but the ice can spread. I have seen icicles form on the front of the appliance!

Cold condenser coils are used within a refrigerant dehumidifier to extract moisture from the air.

These condenser coils can become covered with frozen water, causing issues with the whole dehumidifier.

Other types of dehumidifiers, like desiccant dehumidifiers, won’t freeze over, because there are no condenser coils.

If your refrigerant dehumidifier has frozen then there are 4 common issues:

1. Low Room Temperature

does dehumidifier ice up

A dehumidifier evaporator coil can freeze in temperatures below 60 degrees Fahrenheit.

The refrigerant within the evaporator coils can’t handle temperatures that low and will make the dehumidifier freeze internally.

In most cases, the fan blades will still draw air in, but the dehumidifier won’t cool the air or draw any moisture out.

This is the most common reason I’ve seen for dehumidifiers freezing over.

Solution

The simplest solution to stop the dehumidifier icing up is to move it to a warmer room.

If you can’t move the dehumidifier then I would recommend using a heater so the room returns to an ambient temperature.

As the temperature rises the warm air will unfreeze the cold coil and it will be able to remove excess moisture again.

ACLAB Note:

You also need to consider if you have the right type of dehumidifier for the conditions. There are specialized dehumidifiers that are suitable for very cold weather.

Basements, garages, and crawl spaces all have a lot of excess moisture, but they can be very cold.

In these spaces, standard refrigerant dehumidifiers will have issues, so I would recommend buying a specialist model or a desiccant dehumidifier.

TL;DR: Low room temperature is one of the most common causes of dehumidifier freezing up. Refrigerant dehumidifiers aren't designed to work severely cold weathers.

2. Blocked Air Flow Or Faulty Fan

Poor airflow can mean your dehumidifier freezes because the condensed water doesn’t drip into the water tank.

Instead, it remains on the coils and will freeze, leaving you with an iced-up dehumidifier.

Poor airflow can be caused by a faulty fan motor or by a dirty air filter which is causing a blockage.

It can also be because the dehumidifier is placed near walls or furniture which blocks the dehumidifier fan and restrict airflow.

Solution

First, clean the dirty filter and move the dehumidifier so there is 3ft. of clear space on all sides to allow for adequate airflow.

I would recommend placing the appliance in the center of the room and getting into a routine of cleaning the filter every 1-2 months.

If this doesn’t work you may have a broken fan motor. Check for a defective fan motor by running it on high and seeing how much forceful air is being generated.

If there is no noticeable air coming from the air filter you’ll need to replace the fan inside the dehumidifier.

TL;DR: A dehumidifier with obstructed airflow can condensed water freezing up inside. Make sure, the dehumidifier is placed away from walls or objects.

3. Lack Of Cleaning & Maintenance

how to clean a dehumidifier
If your dehumidifier isn’t properly cleaned or maintained properly it can lead to blocked air filters and internal damage.

This can impact how the dehumidifier works and cause it to freeze over. Dirty air filters can also negatively impact your indoor air quality.

Solution

Regularly clean and inspect the device, making sure that the coils do not have ice and that the fan is not blocked.

Remove all dust with a warm washcloth and fully clean the tank with an antibacterial cloth (think Chlorox or Lysol).

The most common reason I see for dehumidifiers breaking down is a lack of maintenance.

I would recommend cleaning your dehumidifier once a month at a minimum. This includes removing the largest pieces and cleaning the interior of the machine.

TL;DR: A dirty and clogged dehumidifier can lead to it icing up. Make sure you perform regular cleaning and maintenance.

4. Sensor Failure/Faulty Coils

Most dehumidifiers work using a humidity and temperature sensor.

When there is too much moisture in the air it will tell the dehumidifier to turn on, and when there’s dry air it will tell the dehumidifier to turn off.

A faulty humidity sensor or humidity control can cause the appliance to run for too long.

This means the hot condenser coils stay cold for longer, which can cause them to freeze over.

Solution

If you notice that your dehumidifier works even when it’s not humid in your home it’s probably a sign that there’s a faulty sensor.

ACLAB Note:

When dealing with bad internal components you should consult a professional who can do repair work but it can get expensive, so for small portable units it’s often cheaper to buy a replacement.

TL;DR: A bad sensor can cause it to run for longer than necessary leading to condenser coils icing up.


How To Fix A Dehumidifier That Has Iced Up Already?

Your dehumidifier will not work properly if it’s iced up so you can’t just leave it to run.

If you notice your dehumidifier freezing, then you need to act quickly or it can cause permanent damage to the appliance.

Here’s what you need to do:

  1. 1
    Empty the tank and remove any excess water.
  2. 2
    Unplug the dehumidifier.
  3. 3
    Move your dehumidifier to a warmer room or somewhere higher within the room (on a shelf or table). Heat rises and the warmer air will help to thaw out the evaporator coils.
  4. 4
    Remove the air filter and clean it with warm soapy water. This should remove any ice.
  5. 5
    Check the fan behind the air filter and look for any visible damage or blockages. If the fan is damaged, it may need to be replaced.
  6. 6
    Heat the room so it’s over 70 degrees. This should thaw out any remaining dehumidifier icing in the appliance.
  7. 7
    Leave the dehumidifier for 12-24 hours in the warmer room so all the ice has melted.
  8. 8
    Clean and dry the dehumidifier and replace all parts. I find it best to leave them for 24 hours so each part is completely dry.
  9. 9
    Reconnect the dehumidifier and turn it on. It should now be de-iced and working properly.
  10. 10
    If the dehumidifier still isn’t working or starts icing up again then I would recommend consulting a professional for help.

TL;DR: Turn the dehumidifier off and place it in a cozy 70 degrees (Fahrenheit) room for 12-24 hours. Make sure you perform thorough cleaning in the meantime.


Preventing The Dehumidifier To Freeze Up (Tips And Tricks)

It’s much easier to prevent your dehumidifier from icing over than it is to remove ice that’s already formed.

Here are the best ways to keep your dehumidifier from freezing:

Keep The Temperature Above 60 Degrees

If your dehumidifier gets below 60 degrees there’s a risk it will freeze. Check the temperature of the room you’re placing it in and make sure it’s not too cold.

Moving your dehumidifier to a higher location in the room is usually advisable because the air is warmer, but in some cases, you may need to run the dehumidifier alongside a heater to stop it from freezing.

Don’t Use It In Winter

Humidity levels peak in summer and even though it’s wetter in winter, I don’t need my dehumidifier anywhere near as much.

If you avoid using it in the coldest months you can prevent it from freezing over and save on your energy bills.

Run It In Short Cycles

Run your dehumidifier in short 2-3 hour cycles. This stops the condenser coil from running too long and freezing over.

I’ve also found this achieves the is more energy efficient in my home and it saves me money on my bills.

how long to run dehumidifier

Clean The Dehumidifier Monthly

Clean the dehumidifier regularly and remove any blockages from the filters.

You should also scrape any existing ice or debris off the internal components to stop any issues in the future.

TL;DR: Regular cleaning and refraining from operating it in cold temperatures is the best way to prevent dehumidifier from icing up.


What Will Happen When They Freeze Up?

Fan Motor Malfunction

Ice will form on the cold coils within the dehumidifier but eventually, it can spread to the fan motor.

This sensitive electrical component shouldn’t be near any water and if it’s touching ice then it may cause the whole dehumidifier to stop working.

You’ll notice if the fan is broken because no air will go in or out of the dehumidifier.

Jammed Up Blower Wheel & Fan Blade

The blower wheel and fan blade won’t work on a frozen dehumidifier.

The ice can stop them from moving properly and it can cause permanent damage. This will stop air from blowing out of your device.

Humidity Management System

The humidity management system is the set of sensors that tell the dehumidifier when to run and how much dehumidification is needed.

It usually includes a bi-metal thermostat and humidity sensor.

When the dehumidifier is frozen it won’t be able to remove moisture.

This can lead the humidity management system to keep your dehumidifier running constantly, which can cause more frost and other long-term damage.

If this system is damaged then you’ll notice your dehumidifier isn’t turning on and off correctly.

It can become permanently damaged, which means expensive repairs or a completely new dehumidifier.

TL;DR: If the dehumidifier ices up, not only will it not regulate moisture, it will also start damaging internal components.


FAQs

How Does Auto-Defrost Work On A Dehumidifier?

Auto defrost is a setting on dehumidifiers that automatically thaws ice to prevent freezing. An external sensor works to detect ice and when it does it will turn off the compressor system within your dehumidifier.

The fan typically stays on so that the room-temperature air can help thaw the compressor. Not every dehumidifier has this setting, but when they do, it is convenient.

Do Dehumidifiers Work In Very Cold Temperatures?

Refrigerant dehumidifiers should not be used in temperatures below 60 degrees Fahrenheit because it can cause the condenser coils to freeze over.

Other types of dehumidifiers, like desiccant dehumidifiers, can be used in lower temperatures as there are no coils.

What Should I Set My Dehumidifier To In The Winter?

Winters tend to be drier than summers so you can set your dehumidifier a bit higher.

Aim for 45-50% relative humidity during the winter months and 35-40% during the summer months.

Do Dehumidifiers Work Better In Hot Or Cold Rooms?

Dehumidifiers work best in hot rooms because they use cold coils to condense and remove moisture from the air.

However, as long as the room is above 60 degrees Fahrenheit, it should be fine in any room.

Conclusion

I have helped repair lots of frozen dehumidifiers over the years but unfortunately, sometimes the damage is irreparable.

If you notice ice on your dehumidifier, then you need to act quickly. Thaw out the appliance and try to find out what the issue is as soon as possible.

Hopefully, this guide has helped to explain what has left you with a frosted dehumidifier and shown you how to prevent your coils freezing in the future.

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Josh Mitchell

Founder

Josh Mitchell
My name is Josh and I am obsessed with home appliances. From portable AC units to heaters and air purifiers, I enjoy testing, learning and using these devices to improve the air quality inside my family home.

My Favorite Home Appliance?

Midea U Shaped Window Air Conditioner

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