Air Purifier vs. Dehumidifier: Which One to Choose?

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As air pollution gets worse with each passing year, the air we breathe become more contaminated. When combined with unreasonably high humidity, air pollution can really impact air quality inside your house.

As a result, your health – especially your respiratory system – can take a big hit.

To improve the air quality in your home, you can use a dehumidifier or an air purifier

However, these appliances cannot be used interchangeably, and they perform different functions.

So, which one is the most suitable choice for your home? To understand that, you need to first understand the key differences between an air purifier and a dehumidifier. 

In this short guide we tell you everything you need to know to make the healthiest choice for you and your family. 

So let’s dive in!

The key differences between an air purifier and a dehumidifier

difference between air purifier and humidifier

When it comes to dehumidifying a home, many people believe that an air purifier and a dehumidifier provide basically the same function. 

However, that’s not true. 

Here’s a breakdown of the key differences between these two devices to help you understand this better.

Understanding an air purifier 

difference between air purifier and humidifier

The air inside your home contains a range of airborne contaminants like mold spores, allergens, dust and other similar particles that damage air quality.

It is essential to get rid of these pollutants, especially mold, since it can be dangerous. 

In fact, breathing in mold spores can result in both short and long-term health complications. WHO and CDC studies show that people with mold sensitivity can experience significant problems with asthma and skin irritation.

Plus, mold spores can also lead to coughing, eye allergies and nasal irritation. Meanwhile, long-term exposure can lead to life-threatening diseases like cancer, neurotoxicity, immunologic disorders, and renal toxicities.

Mold spores also travel fast: they are similar to flower pollen and can float from one part of the house to the other with the slightest draft. So, mold spores can spread all around a house dangerously quickly.   

This is where an air purifier comes in handy. It features a number of internal filters, and the air inside your home is circulated through these filters to remove most of the contaminants present in the air. 

Air purifiers are usually of one of two basic types:   HEPA, or activated carbon

HEPA filter 

does air purifier help with dust

An air purifier with a HEPA filter shows exceptional results. 

HEPA filters can trap up to 99% of airborne contaminants. Plus, they can easily capture contaminants as small as 0.3 microns.

Air passes through multiple layers of filters to eliminate pollutants. Clean air is then pushed into the room. 

One problem with a HEPA air purifier, however, is that you need to change filters regularly to maintain performance.   

Activated carbon filter

what does a dehumidifier do

Mold and mildew lead to damp, musty smells. An activated carbon filter works to remove these smells from the room.

Note that an activated carbon air purifier cannot control or reduce the moisture level of the room. Instead, it only recirculates the home air, which gets rid of the air pollutants.

Understanding a dehumidifier 

what does a dehumidifier do

While the basic function of an air purifier is to get rid of airborne contaminants, a dehumidifier, as the name suggests, eliminates excess humidity from the room. 

A dehumidifier takes in humid air from the room, removes the moisture and releases dry air. The collected moisture goes into a collection tank that you need to empty and clean regularly.

Ideally, your room should have a humidity level below 50%. In order to maintain that, you need a dehumidifier. 

Dehumidifiers can be one of two kinds depending on how they function. One functions using refrigeration, in which the unit cools the air to get rid of the excess moisture, then warms it up again and releases it back.

Other units work on the basis of adsorption/absorption. In the former, moisture sticks to a material in the unit, which you then take out. Meanwhile, in the latter, a material absorbs all the moisture in the air to remove it.  

If you often find mold around the house or see condensation on your windows, chances are the air around you is too humid. Apart from being a breeding ground for mold, high moisture also attracts dust mites.

So, lowering the humidity with the help of a dehumidifier reduces the chances of mold and dust mites thriving. 

Low humidity also helps you relax since high moisture makes you warm and uncomfortable. 

What Does a Dehumidifier Do?

To put it simply, a dehumidifier takes out water from the air, making it difficult for dust mites, mildew, and mold to grow and thrive. 

What Does an Air Purifier Do?

An air purifier basically circulates the home’s air through a filter present inside. This traps contaminants present in the air, including dust mites, smoke, and pollen. As a result, the air moving around in your house is cleaner and, thus, easier to breathe.

Types of Air Purifiers

There are various types of air purifiers, with each boasting one or more of the following cleaning technologies:

HEPA filters

A HEPA filter is known to be highly dense and traps airborne contaminants. The best type of this filter is the True HEPA filter since it can remove up to 99.97% of particles, even those that are as small as 0.3 microns. So, a HEPA filter can effectively remove pet dander, mold spores, smoke, allergens, dust, and particulate matter. 

does air purifier help with dust

Carbon filters 

Such filters are made of highly adsorbent activated carbon that traps VOCs (volatile organic compounds), gases, chemicals, and odors. They not only remove toxic substances but also keep the room smelling fresh. 

Negative ionization

dehumidifier for allergies

This technology releases charged ions in the air that attract airborne pollutants. Since this weighs particles down, it is easier for the internal air filters to capture them. It also causes the contaminants to stick to the surrounding surfaces and fall to the floor. Negative ionization is quite effective and can remove particles as small as 0.01 microns.

UV Light 

UV light can kill viruses, bacteria, and airborne mold by destroying their molecular DNA structure. As air goes through the air purifier, the UV light breaks pathogens, fungi, and microorganisms, leaving behind sterilized and clean air. 

Photocatalytic oxidation

This technology uses broad-spectrum UV light that reacts with a film of titanium oxide, causing oxidation. This method cleans the air with the help of oxidation since it helps in decomposing microorganisms.

Ozone generator 

air purifier vs dehumidifier

This is essentially a fake purifier that does more harm than good, and it’s best if you avoid them. An ozone generator splits the oxygen molecules present in the air into single atoms. These then merge with other oxygen molecules and form ozone, which is bad for the health since it can damage the lungs and further worsen asthma for asthma sufferers. 

Electrostatic precipitators   

An electrostatic precipitator works on the basis of ionization. The only difference is that there’s a collector plate for the dropped particles. 

Types of Dehumidifiers

Dehumidifiers are typically of two types, cool mist, and warm mist. Despite the differences in their working mechanism, both kinds affect the moisture air in the air and reduce humidity.

Dehumidifiers can be further categorized as:


Such dehumidifiers use a refrigeration process that cools a metal plate where the moisture in the air condenses. Then, a fan draws air via the dehumidifier. The moisture then drips into a collection tank.

Mechanical or refrigerative dehumidifiers are most effective in places with high ambient temperatures where the humidity is over 45%.  


dehumidifier for allergies

These dehumidifiers use a special material that can absorb humidity. It is quite similar to silica gel that usually comes with electronics. A wheel containing desiccant inside the dehumidifier slowly turns through the incoming air and absorbs the moisture in the air.

It is the best choice for places with up to 35% of humidity. 


does a dehumidifier help with allergies

Electronic dehumidifiers feature a Peltier heat pump that generates a cool surface to condense the water vapors in the air. You can then drain the condensed water.

Since these dehumidifiers don’t have any moving parts, they don’t make much noise when operating. However, they are not really energy-efficient and are only suitable for smaller areas.

Ionic membrane 

A special type of ionic membrane is used as an ionic pump to extract humidity at the molecular level from sealed enclosures. Such dehumidifiers are ideal for use in industrial areas with water improvement, chemical, or fuel cell applications.  

Makeshift dehumidifiers

These are basically window ACs that work similarly to refrigerative dehumidifiers. These function by sending back the heat exhaust into the room. 

Air purifier vs. Dehumidifier: Key Features 

Whenever you’re in the market to buy an air purifier, here are some things to keep an eye out for:

Change filter indicator

Make sure that the unit you buy has an indicator light that signals when you need to change the filters. This helps to keep your air purifier working at its optimum level.

Smart control

While most air purifiers come with some kind of remote control, recent models now feature smart connectivity that allows you to control your unit wirelessly, either from a tablet or a smartphone. 

Quiet operation

Of course, everyone would like to have a powerful unit that can purify the air quickly and efficiently. However, you wouldn’t want it to keep you up all night. So, when choosing an air purifier, make sure that it doesn’t produce a lot of noise. 

Eco Mode

If you often worry about high energy bills, look for a unit that features an Eco mode. This mode can either keep your air purifier on standby or simply turn it off when it doesn’t detect indoor pollution for thirty minutes.

So, the eco mode works as a great energy saver and is definitely a nice feature to have. 

Meanwhile, if you want to buy a great dehumidifier, make sure to look out for the following features:


dehumidifier vs air purifier

A humidistat lets you program your dehumidifier such that it maintains the desired level of humidity in the room. Generally, 30 to 50% of humidity is ideal for comfort.

A humidistat can be in different forms depending on the model; it can either be a number setting, or it could just be a low, medium, or high setting option.

Tank capacity

Water Tank Capacity

To make sure you make the most of your dehumidifier, you must choose the right size depending on the room where you plan to use it. Your chosen unit should be able to extract enough moisture from the air without wasting energy or working too hard.

For a large room, like a living room, it’s best to go for a unit with a medium to large tank. While such units do cost more, they provide more convenience.


If you don’t have time or find it a lot of hassle to drain your dehumidifier’s bucket every time manually, make sure you get a unit with a drain port that you can connect to a gravity hose or a condensate pump.

Both of these will ensure automatic drainage, taking away the hassle.

Programmable timer:

To make sure you breathe in air with the ideal humidity when you get home, it’s best to choose a unit that you can program to turn on before you reach home and switch off when there’s no one at home.  

Buy an Air Purifier if:

does a dehumidifier help with mold
  • There’s no musty mold smell at home. 
  • Odors from smokers, cooking, or pets stay in the air and irritate the lungs and eyes.
  • You want a dust remover to help reduce dust and have a healthier environment at home. 
  • Someone in your family suffers from respiratory issues, allergies, or asthma and needs clean air to breathe.  
  • The air in your home maintains the ideal humidity levels. 
  • You want to get rid of pet dander and allergens from your home.  

Buy a Dehumidifier if:

does a dehumidifier help with mold
  • You live near or along the coast, where the air is very humid. 
  • You find excess condensation or moisture on your pipes or windows.
  • Your home often smells musty or has the characteristic smell of fungi, mildew, and mold. 
  • You want to prevent dust mites from spreading. 
  • You want to slow down or reduce the growth of mold in your basement. 
  • Someone in your family has respiratory problems, and humid air only makes them worse.  

Price & Maintenance 

Maintenance and Price

Whether you buy a dehumidifier or an air purifier, maintenance is important. When it comes to dehumidifiers, it’s best if you clean them weekly. You will have to empty the bucket and wash the permanent filter and the plates.

You will also need to clean the coils and buckets frequently. You should also check the coils for frost since it can decrease your unit’s efficiency. Regularly cleaning your dehumidifier can extend its lifespan and prevent mold growth. 

More often than not, people buy a dehumidifier to place it in their basement since there’s no sunlight and the ventilation is poor. A dehumidifier usually has a typical box shape and is available in different sizes to house the reservoir.

The good thing is there are no recurring filter costs when it comes to a dehumidifier.    

Meanwhile, the maintenance of air purifiers involves replacing the filters after every six months. To know when it is time to change the filter, look out for the filter indicator light, or you can just follow manufacturer guidelines.   

Some units also feature a washable filter that you need to clean periodically. Generally, owning an air purifier can be a bit expensive because of the recurring costs of the filters. The price of filters varies from as low as $10 and goes up to $1000.

Energy Efficiency

Energy Consumption

Considering all the factors, both devices will cost you the same in terms of energy costs. Whether it is an air purifier or a dehumidifier, the average monthly cost, if it runs all day, should be $6-10, depending on the electricity rate and your model’s wattage.   


Can you use a dehumidifier to get rid of mold?

Prevent Mold with Dehumidifier

While both air purifiers and dehumidifiers help with mold, it is best to choose the latter. A dehumidifier removes the extra moisture from the air, thus inhibiting the growth and reproduction of mold.

On the other hand, an air purifier can get rid of the mold spores present in the air, but it cannot terminate the problem at its root. 

Can a dehumidifier help deal with allergies?

Again, while both devices can help, an air purifier is a better choice in this case. Air purifiers remove the pet dander, bacteria, dust, mold spores, and allergens present in the air. However, a dehumidifier can only inhibit mold growth and the spread of dust mites. 

Is a dehumidifier more suitable for dealing with dust?

does a dehumidifier help with allergies

When it comes to dust mites, you can benefit from using both air purifiers and dehumidifiers together. An air purifier traps and gets rid of the dust from the room, thereby eliminating the dust mites’ food source.

Meanwhile, a dehumidifier lowers the humidity, ensuring that dust mites can’t thrive. 

Is it possible to use an air purifier and a dehumidifier in the same area?

Yes, there’s no problem with using a dehumidifier and an air purifier in the same room. Just make sure to leave some distance between them so that they do their job efficiently.

Can a dehumidifier clean air?

dehumidifier for allergies

This is the prime difference between an air purifier and a dehumidifier; the latter cannot clean the air. It can only help maintain the ideal humidity level by removing the excess.

However, it does contribute towards cleaning the air; it prevents bacteria, mold, and other particles from growing, which could otherwise cause health issues.

Can an air purifier eliminate cigarette smoke?

A HEPA-rated purifier can drastically lower the cigarette smoke particles in the air, while HEPA air purifiers with chemical adsorbents can get rid of smaller VOCs, too.

However, the only way to completely get rid of cigarette smoke is to avoid exposure to it.   

Is a dehumidifier or air purifier better for the basement?

If your basement suffers from a basement issue, you will need both an air purifier and a dehumidifier. The former will trap the mold spores already present, while the latter can help get rid of the excess moisture.

Can a dehumidifier cool the room?

Yes, since dehumidifiers reduce humidity, they can clean a room. High humidity levels in the air can make the room feel hotter due to the excess moisture.

However, dehumidifiers can remove the water vapor and make the room feel cooler.  

Where should I place my dehumidifier?

Ideally, you should place a dehumidifier in a room with moisture problems. Try to keep it as close to the room’s center as possible so that it can extract water vapor from throughout the room. 

Can an air purifier dry out air?

An air purifier cannot dry out air since it does not remove moisture from the air. It only traps the particles present in the air with the help of the filters present inside. So when the air purifier is running, there’s no change in the relative humidity of the air.

Air purifier vs. Dehumidifier – which one to purchase?

Since both dehumidifiers and air purifiers have their own specific functions, it’s impossible to name one of the two essential; it all boils down to your needs. While an air purifier helps reduce contaminants in the air, a dehumidifier lowers the moisture to make the area less humid.

So, when deciding between the two devices, consider the problems you are facing and then choose accordingly!

  • Purpose

  • Beneficial for

  • Gets rid of

  • Suggested humidity

  • Types

  • Size range

  • Purifies Air

  • Filtration

  • Humidity Level

  • Noise Level

  • Average Cost

  • Maintenance

  • Air Purifier

  • Uses air filters to remove airborne contaminants and circulate clean air

  • Asthma patients and allergy sufferers

  • Smoke, bacteria, mold spores, pet dander, allergens, dust, etc

  • Varies

  • UV lights, adsorbents, ozone generators, ionizing, filter

  • Small to large

  • Yes

  • Multi-stage

  • Not affected

  • Soft to Loud

  • High

  • Quarterly to yearly check

  • Dehumidifier

  • Extracts moisture from the air, lowering the humidity level of the room

  • Allergy sufferers; also lowers damp odors

  • Dust mites, mildew, and mold

  • 50%+

  • Makeshift, ionic membrane, electronic, desiccant/adsorption, air conditioners, refrigerative/mechanical

  • Small to large

  • No

  • Single

  • decreases

  • Average to loud

  • Average

  • Needs regular cleaning and maintenance

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