Dehumidifier vs Air Purifier [Key Differences]

Air quality is a big concern for people, especially in the age of pandemics and airborne viruses. Dehumidifiers and air purifiers both impact air quality and can improve our comfort level within our homes. So, what’s the difference between them and which one is best for you? 

Dehumidifiers remove moisture from the air, reducing humidity and helping with mold, mildew, and allergy problems. Air purifiers are normally more expensive. They filter particles from the air, helping reduce dust, allergens, pet dander, and other airborne particles that may contribute to illnesses.

Dehumidifier Versus Air Purifier

Dehumidifiers and air purifiers both work to improve indoor air quality. Still, there are many differences between the two pieces of equipment. You may need both to address the issues in your home, or you may only need one or the other. Understanding the differences and similarities will help you make the best choice for your situation.   

Dehumidifier Air Purifier
Cost$50 – $350+$50 – $1,000+
PurposeRemoves moisture from air, reduces humidity level Removes particles/contaminants from air
TypesRefrigerant, Desiccant, portable, whole-house (HVAC)HEPA filtered, UV light, carbon filter, ionizing, whole-house (HVAC)
Useful ForMoist, damp areas, reducing mold and mildew growthAllergies, asthma, odors, smoke, and other removing other particles 

There are dehumidifiers and air purifiers available in many different price ranges. However, air purifiers can be very expensive if you’re looking for a unit with the most advanced technology. 

If you’re looking to remove moisture, dampness, and a musky feel from your home or an area in your home (like a basement or attic), a dehumidifier may be the way to go. Dehumidifiers can also help with the temperature controls in your home if moisture is a big problem where you live. 

However, dehumidifiers won’t do anything to help clean the air or remove pesky particles that you don’t want to breathe in. 

If you want to improve the conditions for allergy sufferers, reduce dust and pet dander in the air, or address smoke and other odors, you’ll need an air purifier for that. Air purifiers are quite effective at removing allergens from the air, especially if you’re sensitive to pollen and pet dander. 

However, if you’re dealing with mold and mildew or a musty, damp smell, a purifier won’t help with that. 

What is a Dehumidifier?

A dehumidifier is a piece of equipment that removes moisture from the air. In areas where humidity is high, the moisture content in the air can cause problems for people inside their homes. Dehumidifiers normally cost between $50 and $300 or more. 

Too much moisture can lead to mold and mildew, cause odors in the home, or exacerbate allergy or asthma problems. Most people are comfortable with a relative humidity level of around 50%. When the humidity level is higher than that, you may want to use a dehumidifier to remove moisture. 

Dehumidifiers work by condensing air to remove water molecules. Air is sucked into the dehumidifier and passes over a coil or coils that are cooled to a very low temperature. 

As the warm or room temperature air is cooled, it condenses down forming water vapors. The air that comes out of the machine is now drier than the air that went in. 

There are several types of dehumidifiers, but they all do the same job. Let’s take a look at some of the most common varieties. 

  • Refrigerant: These are standard dehumidifiers where moisture is removed through the cooling process. As air is cooled it condenses, causing water to collect inside the machine. The cooled, dry air is recirculated into the room. 
  • Desiccant: In rooms that are already cooler than average, a desiccant dehumidifier may be used instead. These units remove moisture from the air using a chemical agent. These are more common in non-residential settings. 
  • Portable Dehumidifiers: These are smaller, lightweight units that can be transported from one space to another. If you’re dealing with a leak or flood, you’ll probably use a portable dehumidifier if needed on a temporary basis. 

Who Needs a Dehumidifier? 

If you live in a place where humidity is a problem, like in hot, moist climates or near the coast, you may have issues with moisture levels inside your home. Homes or rooms with moist, musky odors may have mold and mildew growth due to excess moisture. 

People dealing with dust mites may also find a dehumidifier helpful, since mites typically thrive in damp, humid environments. 

Other times a dehumidifier may be useful is if you’re dealing with a recent flood or leak inside your home. Excessive moisture in the air will make it harder to get a flood cleaned up as it will take longer to get everything dried out. 

Here are some other signs and symptoms that you may have too much moisture in the air: 

  • Dampness (especially in basements, attics, bathrooms)
  • Condensation buildup on windows, mirrors, walls
  • Musky, damp odors 
  • Mold and mildew growth 
  • Indoor humidity at or above 60%

ALSO READ: Different Types of HVAC Compressors

What is an Air Purifier? 

An air purifier works by helping to circulate and filter the air inside a space, capturing particles, dust, smoke, pollens, allergens, and other contaminants before expelling the filtered (purified) air. 

Unlike a dehumidifier, an air purifier does not remove moisture content from the air. So, if you have a problem with mold and mildew, an air purifier may not solve your problems. 

There are several different types of air purifiers. The kinds of particles the purifier will remove from the surrounding air depend on the type of purifier. Let’s take a look at some of the most common air purifier types and what they do. 

  • Ultraviolet Air Purifiers: These purifiers use ultraviolet (UV) light to destroy harmful bacteria, viruses, mold spores, and other pathogens. These are typically small units that filter air through a UV light chamber. These kinds of purifiers may cost anywhere from $50 to $800 or more depending on the size and model. 
  • HEPA AIr Purifiers: These units use HEPA air filtration to remove 99.7% of particles from the air (as long as they’re at least 0.2 microns or larger). These are some of the most effective purifiers on the market for removing allergens and other pollutants. However, they’re not effective for very small viruses and bacteria. They normally cost between $40 and $350 or more. 
  • Activated Carbon: Air purifiers that use activated carbon are best for removing odors, especially for spaces where smoke or gas fumes are a problem. Often, these kinds of air purifiers also include HEPA filters. On their own, they may not be as effective at removing dust, pollen, and mold from the air, but activated carbon air purifiers are the only ones designed for removing odors. These units are typically priced at $100 and up.
  • Ionic Air Purifiers: These are normally larger than other purifiers, but they’re also very quiet. They work by emitting negative ions into the surrounding air which bond with dust, pollen, and other particles. Once the positively charged particles bond with the ions, they get heavy and fall out of the air. These normally cost between $40 and $300 depending on the unit’s size and model. 
  • Permanent/Installed Air Cleaners: These purifiers work alongside your home’s HVAC system to clean the air circulating through your entire home. They normally use HEPA filters and positive ion technology. These air cleaners are more expensive because they require professional installation, but they are very effective at removing over 99.9% of allergens and particles from the air.

Who Needs an Air Purifier?

Air purifiers may be beneficial for people with allergies, asthma, or compromised immune systems. Still, many people purchase air purifiers because they want to improve the air quality inside their home. 

An air purifier can help remove odors, especially those associated with smoke, pets, gasses, and other contaminants. 

Also, anyone who lives in an area with high-chemical content or where chemical gasses are present should consider an air purifier to remove pollutants and other dangerous contaminants from the air inside their home.  

The Bottom Line

Dehumidifiers work to remove moisture and humidity from a space. Air purifiers circulate the air and reduce the particles and pollutants so you won’t breathe them in. Both items improve air quality, but they do so in different ways. 

Aside from the cost and purpose, you may also want to consider the ongoing maintenance of owning a dehumidifier versus an air purifier. If the unit requires filters, especially if they’re high quality HEPA filters, they may be expensive to replace. That’s an added cost you’ll need to consider, otherwise the unit won’t be working properly. 

With a dehumidifier, you’ll need to think about where the water goes once the machine removes the moisture from the air. Most units have some kind of collection tank for the excess water, so that means you’ll need to empty the tank and keep it clean. 

Moisture buildup can lead to the development of mold and mildew, and you won’t want that mixed in with the air circulating through the machine and into your home. 

We all want to breathe clean, healthy air, especially inside our homes. Choosing the right equipment, whether it’s an air purifier or dehumidifier, can help improve the air quality and keep you and your family comfortable, safe, and healthy. 

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