Difference Between Air Purifier and Dehumidifier

Edited by Diffzy | Updated on: October 02, 2023


Difference Between Air Purifier and Dehumidifier

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Air purifiers and dehumidifiers are increasingly becoming invaluable to people because of the different purposes they serve and the benefits they offer. Some people are unsure whether to buy an air purifier or go for a dehumidifier partly because they do not understand which one they need and partly because they are debating if it is worth buying them.

Good-quality models are well worth purchasing, as they definitely improve the quality of people’s lives. However, people will regret it for the rest of their lives if they buy an affordable but less effective model due to budget constraints (do not be like the miserly Scrooge. Even he turned over a new leaf after the ghosts visited him).

As for whether they need an air purifier or a dehumidifier, people have to think long and hard about what problem they are tackling. Is it excess humidity? Do not think further; go out and buy a dehumidifier. Is it the deplorable air quality? Air purifiers are the people’s saviors in that case. After all, they literally offer a breath of fresh air. Dealing with a combination of contaminated air and dampness? It is better to buy an air purifier and a dehumidifier.

Air Purifier Vs. Dehumidifier

Air purifiers remove air contaminants to improve indoor air quality, whereas dehumidifiers reduce excess moisture and maintain the humidity level in the air.

Difference Between Air Purifier And Dehumidifier In Tabular Form

Parameters of ComparisonAir PurifierDehumidifier
UseAir purifiers remove allergens (such as dust, mold, pollen, and dust mite feces), smoke particles, volatile organic compounds, etc. Moreover, they effectively prevent nosocomial/hospital-acquired infections (that is, they remove bacteria and germs!).A dehumidifier aids in preventing mildew growth and eliminating musty odor as it extracts water from the air.
Working mechanismAir purifiers predominantly use High-efficiency particulate-arresting (HEPA) filters to capture the nasty air particles. People must use activated carbon or other filter types (either as an alternative or supplementary device) to filter out gases and odor molecules.Dehumidifiers pull the excess moisture from the air and collect the water droplets (which may or may not contain microbes and mold) in tanks built for that purpose.
What does it do?It releases clean air into the room.It blows dry air into the room and offers thermal comfort (a state of mind satisfied with the thermal environment. That is, people will not feel too hot or cold.)
Cleaning FrequencyHEPA filters require less frequent cleaning when used along with conventional (usually carbon-activated) filters.People must clean dehumidifiers frequently for the devices to be effective (the plates, if any, in these devices must be washed every week).
Room SizeIt is the preferable option for large rooms, as long as it is positioned in a manner that does not allow air to bypass it.It is much more effective in smaller rooms than the large ones.
BenefitsAir purifier usage helps protect high-risk individuals (the elderly, children, and people with weak immune systems), reduce allergy and asthma symptoms, and sleep better (because of the better air quality).Dehumidifiers protect people’s homes (excess humidity damages walls, floors, furniture, etc.) and increase energy efficiency (when people have air conditioners at home, too).
NoisinessIt is less noisy than a dehumidifier; therefore, people can install it in their bedrooms.It is noisier than air purifiers.

What Is An Air Purifier?

Air purifiers, as the name suggests, purify air. They remove pollutants and allergens (including pet dander) in the air to improve the air quality. These devices are invaluable for people with respiratory health problems. That does not mean only those people should use air purifiers. Fresh or pure air is invigorating and lifts people’s moods. Feeling cranky after a long day at work? Imagine walking into the house only to be welcomed by musty air. Makes the crankiness level increase by a mile, right? Now, imagine walking in and being greeted by fresh, cool air – soothing to the core, isn’t it?

Most people think they need an air purifier if their houses are teeming with air contaminants or when there is a pandemic. That is not the case; all homes, regardless of how often people clean it feverishly, have some allergens or bacteria floating around. Think about how many places people traverse daily. All sorts of unwanted things stick to them and gain entry into the homes. Therefore, people’s immunity systems will thank them for investing in an air purifier.

Types Of Air Purifier

The most popular air purifier types are portable HEPA filters and UVGI. However, other less common air purifiers are available for those looking for something else. The following are the various air purifier types:

HEPA Filters

HEPA filters are the light of people’s lives. They filter (at least) 99.97% of fine particles in the air and are more effective at removing large and small particles than other air purifier types. HEPA filters are portable and do not produce harmful by-products. They reduce bacteria, viruses, fungi, and pollen. What more can one want?

Whole-home Air Purifiers

Do not want to waste time planning where to position the portable air purifiers? Sit back and install a whole-home air purifier into the HVAC system. Sure, this air purifier may not be as effective as HEPA filters, but it does a decent job (removes around 75% of fine particles) and covers a larger area.

Ultraviolet Germicidal Irradiation

UVGI systems use ultraviolet lights to blast bacteria, viruses, etc. However, people will have to install a filter to dispose of the dead microorganisms. As with all portable air purifier types, the right placement is the key to contaminant-free air.

Activated Carbon

Air purifiers with activated carbon adsorb harmful chemicals such as VOCs but are not that effective when removing large particles. That is why these purifiers are used in addition to other filter systems (mostly HEPA filters).

Ionizer Purifiers

These purifiers release ions that attach to airborne particles and electrostatically attract them to collector plates. Ionizer purifiers may be fan-based or fanless. The latter model uses less power but is less efficient at purifying air than the former.

What Is Dehumidifier?

Dehumidifiers are devices that reduce excess humidity. They are not exclusively meant for people living in damp areas. Dehumidifiers are useful installations in any area or room with high humidity or condensation. Basements and bathrooms will benefit a lot from dehumidifiers, as they help prevent water droplets from lingering in a room and reduce the havoc excess moisture causes in homes.

Most people’s basements are already creepy. Add rotting subfloors, grimy-looking wallpaper, and mold to the mix, and people end up with something resembling the basement in The Conjuring 2 (who else was creeped out by Valak?). As for bathrooms, condensation may be helpful if people have a friendly ghost around that uses the fogged-up mirror to communicate (similar to Bobby Singer in Supernatural), but a nightmare otherwise because it leads to mold and mildew development. That is why it is wise to purchase a dehumidifier to remove the condensation.

Dehumidifiers aid in combating the negative effects of excess moisture. Therefore, it makes it difficult for bacteria, harmful microbes, and spores to form; this ensures that people with allergies and asthmatic problems benefit indirectly from dehumidifiers. Moreover, dehumidifiers aid in drying laundry indoors (yay! No more walking out in the scorching sun to hang the clothes on a clothesline.). Some dehumidifiers have a laundry setting. This feature may seem a trivial thing to rejoice over, but many people love it, as it considerably speeds up the drying process.

Types Of Dehumidifiers

Many types of dehumidifiers are commercially available for people to choose from. Some of the popular types are as follows:

Refrigeration Dehumidifiers

These are the most common dehumidifier type. Refrigeration dehumidifiers have an evaporator coil that condenses and removes water in the air. Their condenser coil reheats the air, and the dry air is released into the room/living space. The condensate (water) collected using refrigeration/heat pump cycles is termed greywater, and some models come with reverse osmosis filters that turn the condensate into potable/drinking water (awesome!).

Desiccant Dehumidifiers

Desiccant dehumidifiers combine moisture with hydrophilic materials such as silica gel and absorb it. Though considered more energy efficient than refrigeration humidifiers, they are not as effective in areas with extreme humidity. Therefore, they can help people reduce their energy/electricity bills, but only if the humidity level is something they can handle.

Spray Dehumidifiers

These humidifiers spray chilled water and air to make the body of air reach its dew point (the temperature at which the air becomes saturated with water vapor). Once the dew point is reached, water condenses faster, making it easy for dehumidifiers to capture the moisture. Spray dehumidifiers are called air washers, as they capture contaminants (such as pollen), too.

Makeshift Dehumidifiers

In a pinch, people can modify air conditioners to work as a dehumidifier. This technique is possible as the mechanisms of both devices are similar. However, air conditioners re-evaporate the condensate to dispose of them. To make them work like a dehumidifier, they must be modified to dispose of the condensed water in liquid form.

However, a makeshift dehumidifier is not as effective as the ones commercially sold. And, there is always a chance that things go wrong when modifying an air conditioner unless people know precisely what they are doing. People without the necessary knowledge should not tinker with it unless they want their families to come after them with a knife.

Thermoelectric Dehumidifier

These humidifiers use Peltier heat pumps to remove excess moisture in the air. They work less noisily than dehumidifiers with mechanical compressors (an immense relief to light sleepers). However, only small thermoelectric dehumidifiers are available, as their designs make them consume more energy to provide heating. Ice buildup may be a problem in these dehumidifiers. Some models have ice sensors, enabling them to turn the device off to allow the coils to defrost. So, ice buildup is not a problem if people opt for such models.

Main Difference Between Air Purifier And Dehumidifier (In Points)

  • An air purifier removes/eliminates microbes, spores, bacteria, and allergens. On the other hand, a dehumidifier reduces the chances of their growth/formation in the first place (after all, damp areas are the favorite nesting spaces of these nasties).
  • Only a few types of dehumidifiers are available compared to air purifiers. Moreover, the different air purifier types can be used in conjunction, and the same cannot be said for dehumidifiers.
  • An air purifier will save a person from the harmful effects of second-hand smoke (a serious concern and not a joke). A dehumidifier is less effective in this scenario.
  • Maintaining a dehumidifier is more work than most people think. People have to check periodically whether any of its coils have frosted, besides cleaning the device regularly. Comparatively, air purifiers require less maintenance. At most, people would have to replace the filters every 6 – 12 months (this might rub people with budget constraints the wrong way, but sometimes, spending money is preferable to spending valuable time checking trivial things).
  • Ozone production (despite the low emission) in ionizer purifiers and ozone generators is a concern for go-green enthusiasts. People experience no such inner turmoil when purchasing any dehumidifier type.


People having trouble with indoor air pollution frequently and those with allergies or asthmatic problems will be better off purchasing an air purifier. HEPA filters are the best air purifier type to purchase; ionizer purifiers release ozone as a by-product, causing people’s allergies and asthma to worsen (though this may not be a concern for perfectly healthy people) even if they release less than 0.05 ppm of ozone.

People living in damp areas where the humidity level is more than 50% will benefit more from a dehumidifier. Alternatively, people can buy both and use the air purifier to remove allergens and whatnots and use the dehumidifier later to prevent the formation of allergens, mildew, etc. That way, people get the best of both worlds; they can breathe pure air while enjoying thermal comfort.


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  • https://www.womanandhome.com/life/homes/air-purifiers-vs-dehumidifiers-which-is-best-for-your-needs-386671/
  • https://www.choice.com.au/home-and-living/cooling/dehumidifier/articles/humidifier-vs-dehumidifier-vs-air-purifier
  • https://www.livescience.com/dehumidifier-vs-air-purifier
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  • https://en.wikipedia.org/wiki/Air_purifier
  • https://en.wikipedia.org/wiki/HEPA
  • https://en.wikipedia.org/wiki/Dehumidifier


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"Difference Between Air Purifier and Dehumidifier." Diffzy.com, 2024. Thu. 29 Feb. 2024. <https://www.diffzy.com/article/difference-between-air-purifier-and-dehumidifier>.

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