Air Purifier VS Dehumidifier: Which Is Better?

An air purifier is not a dehumidifier despite both can improve indoor air quality and alleviate allergies. They might look and feel the same, but the functionality is on a different spectrum. In this post, we will touch on every little detail about both home appliances, how do they work, and why do you need one. We will also list down the differences between an air purifier and a dehumidifier with a table comparison. At the end of it all, you will have a better understanding of your needs and make the right purchase.
Short answer
Air purifier cleans air. Dehumidifier removes moisture.


PARTU BS-03 True HEPA Air Purifier

What Does An Air Purifier Do?

An air purifier circulates air through a series of filters and traps airborne contaminants. With harmful particulates removed from the air, you will enjoy breathing in purified, clean air. One will feel a gradual improvement in their health physically and mentally. An air purifier can be placed anywhere indoors with the bedroom and living hall the most popular spot. You can even integrate an air purifier in the ductwork of the HVAC system for whole-house purification.

Types of Air Purifiers

  • HEPA air purifier – High Efficiency Particulate Air (HEPA) filter certified to capture 99.97% microscopic particles down to 0.3 microns. Combine with filters such as a pre-filter, carbon filter, HEPA air purifier can remove any types of indoor airborne contaminants.
  • Carbon air purifier/ deodorizer – Uses chemical adsorbent material to neutralize smoke, chemical fumes, and odors.
  • UV air purifier – A proven and safe sanitization technology powered by a germicidal light. Uses ultraviolet radiation to kill bacteria and viruses by damaging their DNA cells.
  • Photocatalytic Oxidation/ PCO air purifier – Uses broad-spectrum UV light to reacts with a thin film of titanium dioxide resulted in oxidization.
  • Ionizer – Diffuse negative ions to merge with opposite positive ion particles in the air. The charged ions will fall due to increased weight resulting in much cleaner air.
  • Electrostatic precipitators – Works just like an ionizer with an extra collector plate to collect the dropped particles.
  • Ozone generator – An unregulated product that can damage lung tissue cells and aggravate diseases like asthma. Ozonator will split oxygen molecules in the air into a single atom. The single-atom will then merge with other oxygen molecules to form ozone.
frigidaire ffad3033r1 30-pint dehumidifier

What Does A Dehumidifier Do?

A dehumidifier draws moisture out of the air to reduce the room humidity level. By keeping the relative humidity level under 50%, it will halt microorganisms from thriving and spreading in a humid environment. The collected moisture will drip down to a bucket or straight to a drainage hole via a garden hose/ built-in pump. The dehumidifier is often placed in the basement due to poor ventilation with no sunlight. You will breathe comfortably without the damp odors and microbes triggering your allergies or asthma.

Types of Dehumidifiers

  • Mechanical /refrigerative – The most common type that works just like an air conditioner. Moist air is drawn in via a fan to the refrigerated coil for freezing. Through condensation, water will be collected in the bucket, and air will be heated and dispersed as mist. Very effective at ambient room temperatures with RH level above 45%.
  • Thermoelectric/ peltier/ electronic dehumidifier – Drain moisture by converting energy into temperature differences. The heat generated from the heat sinks will create a cool surface for condensation and water collection. With no moving parts to account for, The entire humidification process is silent and energy-efficient. Commonly found in smaller dehumidifiers.
  • Desiccant dehumidifier – Often used in a renewable humidifier due to the smaller parts and silent operation. Works just like a desiccant packet that reduces humidity through moisture absorption material. The rotating wheel belt will automatically collect moisture from the passing air until it reaches its max capacity.
  • Ionic membrane – Micro-size dehumidifier that can be found in electronic devices, fuel cells, and water applications. Designed to be maintenance-free and silent by using an ionic pump to remove moisture from sealed enclosures.
  • Makeshift – An uncommon windows air conditioner that sends heat exhaust back inside the room. Operate similarly to mechanical/ refrigerative dehumidifiers.
The Difference Between Air Purifier And Dehumidifier

The Difference Between Air Purifier And Dehumidifier

An air purifier is not the same as a dehumidifier. The difference is a dehumidifier removes moisture from the air to decrease the relative humidity level. It does not clean the air. An air purifier cleans air by trapping harmful pollutants in the air e.g. dust, dust mite, mold spore, mildew, pollen, pet dander, bacteria, virus, smoke, chemical fumes, and odor. It does not manage the humidity level in your home.

For maintenance, the dehumidifier requires a higher cleaning frequency than an air purifier. The bucket requires emptying and cleaning every 1 to 7 days. Doing so will extend the dehumidifier usage life, inhibit mold growth on the bucket, and prevent the coils from frosting. An air purifier requires less care with filter replacement every 6 to 12 months depending on the filter types. Some models use a washable filter that requires periodic cleaning instead of replacing. With routine maintenance on the filter, an air purifier will last for many years to come.

In general, a dehumidifier is cheaper than an air purifier with a price range between $40 to $400 depending on the size. There is no recurring cost to incur. An air purifier can be expensive to own with a price tag of over $400 for the larger model. You will also need to bear a high recurring cost for the annual HEPA/ carbon filter placement.

Both air purifiers and dehumidifiers will have a big impact on health especially if those with hypersensitive or asthma. An air purifier can relieve allergic symptoms like cough, sneeze, red eyes, sore throat, nausea, or headache. It can also ease seasonal allergies like hay fever, reduce stress, and improve mood levels. In the long run, an air purifier can protect you from diseases like pneumonia, pulmonary edema, respiratory tract damage, sinusitis, COPD, bronchitis, dementia, and even lung cancer due to air pollution. On the other hand, dehumidifiers can alleviate mold-linked allergies and ailments after long exposure. It can also make your home feel less hot and stuffy thus more comfortable to breathe.

FeaturesHoneywell HPA300
Air Purifier
ivation 30-pint ivaldh30pw dehumidifier
DimensionCompact, tower, portable, and consoleMedium to large depending on the reservoir size
FunctionsCirculates clean air by trapping airborne particles and smokeRemove moisture to decrease the indoor humidity level
Alleviate AllergiesYesYes
Help With AsthmaYesYes
Remove DustYesNo
Stop Mold From GrowthYesYes
Best Used InBedroom, living room, kitchen, study room, office, basement, garageDamp places, during summer
  • Mechanical or refrigeration
  • Absorption/ Electronic desiccant
  • Thermoelectric
  • Ionic membrane
  • Makeshift
Noise LevelSubtle to loudSubtle to very loud
Maintenance3-12 months (filter change)1-3 days (empty water)
  • Compact air purifiers ($20-150)
  • Medium-sized air purifiers ($200–400)
  • Large-sized air purifiers (>$400)
  • Mini renewable dehumidifiers ($30-50)
  • Small dehumidifiers ($40-80)
  • 30-pint dehumidifiers ($100-200)
  • 50-pint dehumidifiers ($150-250)
  • 70-pint dehumidifiers ($200-400)
Dehumidifier and Air Purifier In The Same Room

Can You Use a Dehumidifier and Air Purifier In The Same Room?

Yes, you can use an air purifier and dehumidifier together in the same room. Each device runs on different functionality with the air purifier focused on air cleaning and the dehumidifier focus on moisture draining. For the best performance, make sure to keep them at least a few feet apart as excess moisture could clog the air purifier’s filter and reduce its effectiveness.

In conclusion, both an air purifier and dehumidifier are unique in their own ways. If you are still wondering which one to get, below are the summarized points:

An Air Purifier Would Work Best If:

  • Stay in the city or industrial area with heavy outdoor pollution.
  • Dusty home with eyes, throat, and nose irritation.
  • Lingering odors coming from cigarettes, cooking, chemicals like paint, detergent.
  • Allergic to indoor pets like cats, dogs, birds.
  • There is no musty mold smell detected.
  • Home humidity level is between 30%-50%.
  • Suffer from asthma and other respiratory diseases.

A Dehumidifier Would Work Best If:

  • Live in a coastal area or damp environment.
  • Home humidity level exceeded 50%.
  • During the summer season.
  • Musty smell with sights of mold, mildew, and other fungi.
  • Condensation can be seen on windows or pipes.
  • Air feels heavy and hard to breathe.

Which is Better: Air Purifier Or Dehumidifier?

  • Allergies - Both an air purifier and dehumidifier can minimize allergies and allergic reactions like cough, sinus, sore throat, red eyes, itchiness, headache, and breathing problem. Air purifiers removing allergens in the air to prevent them from causing an allergic reaction. Dehumidifiers drain excess moisture so allergens like dust mites, mold, mildew will not be able to thrive and live.
  • Mold - While both devices will help to a certain extent, a dehumidifier is better for mold. Dehumidifiers reduce room dampness and musty smell by absorbing excess moisture in the air. Without a damp environment, mold spores will not able to grow, reproduce, and spread around the house. Air purifiers remove mold in the air and prevent the fungi from settling on a surface area. It cannot help with non-airborne mold that has settled on the porous ground like the wall, sofa, wooden furniture, or ceiling.
  • Asthma - An air purifier is a better option than a dehumidifier even though both devices can help with asthma. An air purifier removes all airborne allergens that can trigger an asthma attack. A dehumidifier drains air moisture to discourages the growth and spread of asthma irritants i.e. mold, mildew. It does not deal with airborne dust and other non-pathogens allergens that can also irritating asthma symptoms.
  • Dust - Air purifier is the winner here. It can clean the air by removing airborne dust in the house. A dehumidifier only removes moisture and is not designed to remove dust in the air. However, it can reduce the humidity level making it less habitable for dust mites.

Do Air Purifiers Dehumidify

Air purifiers do not dry out the air as it does not have the ability to do so. Its job is to filter the air from airborne pollutants and smoke. Only a dehumidifier is specifically designed to perform dehumidification by removing moisture from the air.

What’s Next: Selecting the Right Model

Once you have made up your mind on which appliances to go with, you will need to decide the right model to buy. There are hundreds of devices out there for both air purifiers and dehumidifiers. Each model will vary in performance, equipment, the price range. Most units are designed to handle a type of particulate matter or specific square footage. Last but not least, understand your need and purchase a unit that can handle the required room size. If you need it to cover a 400 square feet basement, choose a model that supports at least a room capacity of 400 square feet. An air quality monitor and hygrometer/ humidity meter will come in handy to keep track of the indoor air condition. For those that needs humidifying and air cleaning, consider getting an air purifier humidifier combo instead.

Max Fernandez

A loving father and a dedicated reviewer for airfuji.com with more than 1000 air purifiers under his belt. Max Fernandez is also one of the million patients currently suffering from asthma. Feel free to nudge him if you have any questions.
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