Why Dehumidifier Has Smell, How To Remove?

Dehumidifier clear and maintenance

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When air conditioner used for a long time, you will feel an unpleasant smell when it running, especially when the air temperature is relatively high ( in summer). When spring enters summer you will find this phenomenon as well. The main reason is that Air Conditioner Filter is already covered with dust.

So, many people clean Air Conditioner once a year, because the dust not only gives off an unpleasant smell but also causes secondary pollution to the environment, which carries a lot of bacteria and viruses, and will affect the health of users.

Dehumidifier will also encounter similar problems. What makes the dehumidifier stink? The stench is usually caused by mold.

If you often smell a moldy odor or a strong sulfur smell from a dehumidifier, usually the source is mold.

The growth of mold needs 4 conditions: no light (ultraviolet ray kills mold), moisture, warm temperature (21 ℃-32 ℃), dust & dirt organic matter.

So where is the source of the odor (mainly from mold) of the Dehumidifier? Let’s give you some knowledge today.

Sources of the Smell


After using a dehumidifier filter for a long time (because the filter has a certain dedusting effect), it will accumulate a lot of dust, which is consistent with the propaganda of many dehumidifier suppliers: it can eliminate smoke.
If the dust doesn’t remove in time, will result in a bad smell.


After the dehumidifier runs for a while, will be lots of moisture on the internal evaporator.

When the dehumidifier turns off, which doesn’t have the function of drying and mildew, will stop running immediately.

So that the internal moisture will always exist, meanwhile it will produce mold and smell for a long time.

After the dehumidification finishes, there will be lots of water vapor on the evaporator. You know, the dehumidifier itself has no drying and anti-mildew function, so can only rely on natural cooling.

In the long-term dehumidification process of the evaporator, there will still be lots of dust, so the dust will become wet, resulting in a moldy and mildew smell.

Dehumidifier Evaporator

Air Inlet And Outlet

This is also a place dust easily accumulates, because of long-term exposure to the air, there will be a peculiar smell.

Meanwhile, more dust is good for more bacteria and viruses, of course, the dehumidifier can remove moisture when working, but the dust (blown out with the wind) will bring out more bacteria and viruses at the same time, which is harmful to your health.

A Dirty Bucket

When your dehumidifier removes moisture from the air, the water gathers in a storage bucket (water tank). Over time, dust particles may accumulate in this bucket.

Dust and dirt as the “food” of mold, coupled with warm water in dark places, can promote mold growth.

dehumidifier wholesale

Water Tank

Fan Blade

Your dehumidifier fan blades may also contain mold and mildew. They come into contact with moist air at warm temperatures, and when dust falls on the blades, it becomes a good place for mold growth.

If the dehumidifier has a bad smell, its dehumidification efficiency is greatly reduced, and the dehumidification effect will perform badly. Especially when the filter is full of dust, it has a great impact on the dehumidification performance, indoor odor is dispersed, causing secondary pollution to the indoor air, and seriously affecting human health.

Other Sources of the Smell

1) The brand-new Dehumidifier (with new materials)  smells like plastic, which will dissipate automatically a few days after usage.

2) Refrigerant leakage probably will cause non-dehumidification and a gas smell.

3) The burning of electronic control system may be causing smell of burning. Please check the electric control box to see the cause of the failure.

4)  If you often smoke, or spray perfume or make-up in the room, then after a long time of air cycle, these odor particles will be adsorbed on the evaporator or filter. So as soon as the dehumidifier starts running, there will be a strange smell.

For that, you must always keep the air clean indoors.

Tips: All of the above are not the regular source of smells, so let’s just briefly mention them here.

how to Get Rid of the Smell?

Clean Storage Bucket

Some dehumidifiers drain automatically, but some dehumidifiers still need to drain manually.

If you own a Modern Household Dehumidifier, you should connect it to your sink, which eliminates the drainage step, but you still need to clean the dirt left in the bucket.

When you discharge water from the bucket, rinse it with a mixture of vinegar and water. Disinfect any mold spores that may still be in the bucket.

Clean Fan Blade

Unplug your dehumidifier power, remove the fan screen with a screwdriver, wipe the leaves with a solution of soap and water (do not use any chemical cleaning agents), remove any debris, such as hair or dirt, reinstall the fan net, and check if have a persistent odor, then clean the fan blade at the meantime.

Fan Blade

Clean Filter Screen,  Air Inlet, And Outlet

you must wipe the air inlet and outlet, then open the panel to take out the filter, rinse and remove the dust, so that there will be no smell.

Clean Evaporator

Actually, you can ask the service company who removes and cleans the air conditioner to help, or after-sale staff the dehumidifier manufacturer.

Note: when buying, try a dehumidifier with a dry and mildew-proof, so its interior won’t easily be damp and moldy.

If you buy a dehumidifier that doesn’t have automatic drying and mildew-proof function, then when no use the dehumidifier, you have to remove the moisture from the internal evaporator, which can also have a mildew-proof effect.

From the below video you can see how to clean the evaporator, but we truly advise you to find service company or supplier to clean inside of the dehumidifier, or Contact Us for help, because DIY cleaning is very easy to damage the machine!



The peculiar smell of Dehumidifier is very annoying, but it exists objectively, so we need to know where this smell comes from, and some methods of how to remove them.

We hope you can learn useful knowledge from this post, and give some help for your daily life.

Any comments?

Welcome leave a message or repost.

About Author

Vic Cheung
Vic Cheung

Hi, I'm Vic! Start working in HVACR field since 2008, our main products included: air conditioning, cold room refrigeration system, water chiller, ice machine, commercial dehydrator, dehumidifier, heat pump, electric motor, and all accessories. Since joined China Speedway Group in 2012, I worked in here more than 10 years, as the general manager of export department, we have established 50+ agent in different countries and areas.
As our experience and strong technical support, we can solve your issue once you have, and our chief engineer has worked in HVACR field since 1997. I am so proud of our knowlege is more and more popular not only for engineer, and for HVACR business new comer, DIY lovers. Hope you are enjoying our articles, if any question or comments just welcome to send me marketing at cn-beyond.com

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China Speedway Group is a professional HVACR products’ manufacturer and wholesaler, we customize different HVACR products and spare parts, especially refrigeration products and parts. Such as air conditioning, refrigeration equipment, cold room solution, ice machine, dehumidifier, electric motor, heat exchanger,copper coil, etc.

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