Do I Need A Dehumidifier If I Have An Air Purifier?

Air purifiers and dehumidifiers both can help make a great difference in your quality of life. But do you need a dehumidifier if you already have an air purifier?

I’ll cover that and much more here. Read on to find out the facts!

Do I need a dehumidifier if I have an air purifier?

do I need a dehumidifier if I have an air purifier section image

The short answer is yes, if you have high humidity or dampness problems but have an air purifier, you still need a dehumidifier. A dehumidifier and an air purifier help with different problems.

Dehumidifier vs air purifier purposes

You’ll want to use an air purifier when dealing with:

  • Allergies
  • Cigarette smoke by-products
  • Odors (not related to dampness like from moisture such as in a basement)
  • Dust mites
  • Pet dander and hair
  • Dust or building material residue

You’ll want to use a dehumidifier when dealing with:

  • You feel hot and sweat much more, such as when tropical or other high-moisture conditions are present
  • Dust mites are growing
  • Moisture or dampness is present in your home

As you can see, these are two very different things and two different goals. Dehumidifiers work by using a refrigerant system (much like an air conditioner) to condense and trap moisture in the air.

Air purifiers circulate the air (without heating or cooling it) and filter out unwanted microbes, dust, dander, and other contaminants which they trap in filters.

How do I know if I need a dehumidifier?

It’s pretty simple to know if you need a dehumidifier. There are two ways you can tell:

  1. By recognizing the effects of high humidity (excessive moisture in the air)
  2. Measuring your air’s moisture using a humidity gauge

If your humidity gauge shows 60% or more, you definitely need a dehumidifier. At around 60% and above the human body tends to begin perspiring more and we feel uncomfortable as we can’t cool off properly, much like when you visit tropical countries and sweat a lot.

ThermPro TP50 humidity and temperature gauge

As seen in the picture here, a digital humidity and temperature gauge makes it a snap to know for sure the humidity level where you are. They’re also affordable and last a LONG time on batteries!

Personally, I strongly recommend using a humidity gauge for better results. That’s because we can’t rely on how our bodies feel at any given time to know the air condition.

How we feel (warm, cool, sensitive or less sensitive) can change from one moment to the next based on what’s going on with us at any given moment.

You’ll want to bring the humidity level down to about 50-55% generally speaking. Less can be fine, but it will mean a dehumidifier will have to run more, consuming more electrical power and driving up your electric bill.

Can you use a dehumidifier and air purifier in the same room?

can you use a dehumidifier and air purifier in the same room

Yes, you can use a dehumidifier and an air purifier in the same room without any problems.

Generally speaking, it tends to be the case that dehumidifiers are used in a basement or an area of the home with mold issues or high levels of moisture. That’s because of how moisture is typically more present in basements due to the damp earth around them.

Air purifiers, on the other hand, are best used in the rooms of your home that you’re in the most and where you breathe the most air or have the most significant air quality problems (such as dust, pets, and so on).

What will a dehumidifier do when near an air purifier?

They’ll work fine in the same room. Because they do such very different jobs, they won’t affect each other and you won’t notice any difference.

However, as dehumidifiers have fans and move air, you don’t want to place one very close to an air purifier as you don’t want to disturb airflow through the purifier. Likewise, you don’t want an air purifier set on high fan speed to obstruct your dehumidifier’s operation.

A dehumidifier will remove excess moisture from the air which makes it harder for mold or mildew to grow, helping to reduce things like mold spores and dust mite growth and activity. An air purifier, on the other hand, will circulate the room’s air and extract and trap these contaminants to ensure the air quality is as good as it can be.

If a dehumidifier is set to make the air significantly less moist (say below 30-40%), some airborne particulates like dust, dust mite by-products, pet dander, and so on can increase as the air is drier. However, this will be offset and dealt with by a good quality air purifier.

Additionally, it’s not recommended to set a dehumidifier that low as it’s below a comfortable level for humans, pets, and especially children. Therefore, it’s wouldn’t make sense for that to happen in the first place.

NOTE: The most important thing to remember is that you must keep your windows closed when using a dehumidifier or an air purifier. Neither one can work as intended if the windows are open!

Where to put a dehumidifier in the room

If you’ve got problems with moisture in areas of your room, then you should try placing a dehumidifier in the center of the room as it’ll be able to draw in moisture from all areas of the room.

Try to not place the air purifier too near to your dehumidifier or near any other electronics in the room as they may interfere with each other. If you’re dealing with a direct source of dampness (such as a leak or outside moisture/air entering a room) then it’s fine to move it closer to that.

You should always follow the manufacturer’s recommendations if provided. Generally speaking, use 1-2 feet from nearby walls at least and at least several feet from an air purifier, if possible.

Where to place an air purifier in a room

These guidelines generally work well for air purifier placement:

  • You should try to place your air purifier in the area (room) where the air quality is the worst.
  • Most air purifiers need roughly 1-2 feet spacing (2 feet is ideal) between themselves and walls or furniture.

Air purifiers of the correct size and Clean Air Delivery Rate (CADR) rating will circulate the room’s air efficiently as long as the airflow is not blocked or restricted. Most work fine on the floor, either in the middle near a wall, the center of the room, or another location such as a corner where airflow is unobstructed.

Notes on using the same electrical outlet

Dehumidifiers that use only several hundred watts are most likely fine, but for larger dehumidifiers with 1,000W or high energy use this can be an issue. For power-hungry models, you’ll want to use outlets from separate electrical circuits for your dehumidifier and purifier.

That’s because in the United States and many other countries, electrical wiring is limited to about 1,500-1,800 watts per circuit breaker or fuse. Too much power drawn and you’ll blow a fuse or trip a breaker. Dehumidifiers, just like air conditioners, use a compressor to circulate refrigerant which requires a lot of electrical power.

What is better for allergies – a dehumidifier or an air purifier?

what is better for allergies dehumidifier or air purifier

If you have allergies to dust, pet dander, or pollen then an air purifier is what you need to remove allergens and irritants and reduce your symptoms greatly.

However, if you’ve got excessive moisture in an area of your home then you could have mold growing which will cause allergies to worsen. That’s a different problem entirely although the symptoms can be similar to allergies.

If you’ve got mold growing in your home, you should get a professional out to sort it and then always continue to use a dehumidifier in that area of your home to keep moisture levels down.

A dehumidifier will also reduce the spread of dust mites and mold growth which can also lead to allergen problems. If mold is a constant issue then you should use both a dehumidifier and an air purifier to keep your allergies under control.

The role of humidity and humidifiers for allergies

If the humidity levels in your home are too low (dry air symptoms), then this can also cause some allergen-like symptoms, so you should consider getting a humidifier to moisten the air. A humidifier allows you to get your room or home’s moisture level up to a healthy and comfortable level, reducing symptoms.

Dry air also brings some other issues directly related to allergy symptoms:

  • The drier the air, the more easily allergens and other contaminants are able to circulate and trigger symptoms.
  • Dust and other material particulates are more easily distributed in dry air.
  • Likewise, pet dander and dust mite contaminants are more present in very dry air.
  • Your nasal and breathing passageways dry out, making you susceptible to irritants and even sickness.
  • Dry skin becomes an issue and people with skin-related disorders will have more problems in a very dry air environment.

An air purifier is more recommended than a dehumidifier for people who struggle with allergies as it’ll reduce allergens in the air and also keep the air nice and clean to prevent any respiratory issues from worsening.

Grant Williams

About the author

Grant is a professional engineer by trade and has experience with both maintenance and do-it-yourself home projects. He enjoys sharing his expertise & ideas with others to help them improve their comfort and quality of life. Read more »

Leave a Comment