Air Purifier vs Dehumidifier: Overview and Comparison

Air purifiers and dehumidifiers are both used to make a home more comfortable for someone. Even though both units will make for a more comfortable home, the way they achieve this is very different.

Let’s take a look at what an air purifier is, what a dehumidifier is, and which is the best choice for you.

What is an Air Purifier?

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An air purifier is a machine that uses a fan to move your home’s air through a bunch of filters. The filters will trap and remove bacteria, dust, and pollen to result in healthier air to breathe. The air purifier will then circulate this new, pure air through your house.

In the same way that a Brita filter makes water clean to drink, an air purifier makes your home’s air clean to breathe.

Pros of an Air Purifier

  • Clean dust and debris from the air
  • Results in clean, breathable air
  • Helps to control your allergies
  • Very small, portable, convenient, and inexpensive
  • Helps people who have respiratory issues

Cons of an Air Purifier

  • Can’t control humidity
  • Often, they’re loud when operating
  • Doesn’t alleviate the need to vacuum regularly
  • Filter changing occurs regularly

Who is an Air Purifier For?

An air purifier is for people who have respiratory issues like allergies or asthma. It should also be considered by pet owners since it removes pet dander and gets rid of odors created by pets. Air purifiers are for home use. They can be used to treat just one room or the whole house.

There are also air purifiers that can piggyback off of your HVAC system. I had a friend whose house air was purified before it even got into the room and it resulted in such a different feel.

What is a Dehumidifier

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A dehumidifier, on the other hand, does not do any type of filtering to the air. It uses a bit more science to operate.

What it does instead is it drains a lot of the water out of the air and collects it in a bucket to be disposed of. Though this might not seem like a big deal, high humidity in-home air will give off a musty smell and make the house feel damp. Another downside to high humidity air is it makes you feel hotter and less comfortable.

The way a dehumidifier works is it draws the house air through this system. The warmer house air will pass over cold coils. This makes the moisture in the air condense on the coils. In other words, the water that used to be in the air in vapor form cools and becomes a liquid on the coils. The water then drips down the coils into a bucket that gradually fills up over time. This is all the water that used to be in your air.

Pros of a Dehumidifier

  • Helps the user deal with humidity and moisture levels
  • Remove musty smells as well as mold
  • Very low maintenance to keep them running

Cons of a Dehumidifier

  • Does not filter or purify the air
  • They are also noisy to operate
  • Could lead to overly dry air
  • Water bucket needs to be dumped frequently (especially in smaller models)
  • A lesser-known function of lower humidity in your air is a higher chance of an annoying static shock

Who is a Dehumidifier For?

A dehumidifier is also for home use. It should be used for rooms that have a musty smell, or for people who have a lot of dust mites in their home. It’s also the go-to tool when it comes to relieving high humidity and the concerns associated.

Due to the different sizes offered, a small dehumidifier can be put into a problem area while the rest of the house goes untreated. In my experience, a small dehumidifier in the basement completely got rid of the smell and make the room way more comfortable.

Key Differences

These two systems are used to tackle very different issues. Though, both lend themselves to a more comfortable home.

Either system will treat the air in your home, and result in a more desirable environment.

Let’s take a look at some of the key differences between an air purifier and a dehumidifier.

How They Work

The big difference between a dehumidifier and an air purifier is how they work. Since an air purifier ushers your home’s air through a ton of filters, it takes out all of the nasty microscopic irritants. The result is clean, breathable air.

Dehumidifiers simply take the water vapor out of the air and condense it over cool coils. What this means for you is the air is less humid and the musty smell is taken out of the room. Of course, since there is no filtration system, a dehumidifier does not result in cleaner or more pure air to breathe.


The other key difference between these two systems is the level of maintenance required. An air purifier requires the user to change the filters on semi-regular intervals. Failure to do so will result in the air purifier to stop working and your home’s air to be unfiltered. Depending on what type of filter you’re using, you might find the filter to be a bit expensive.

The dehumidifier, on the other hand, does not have any type of maintenance like this. There is a lot more upkeep, however. Due to how the system works, all of the water in the air is drained out and dropped into a bucket in the dehumidifier.

The water has no way of draining, so the user will have to take the bucket and dump it outside or into a sink. Depending on how large your system is, this could mean dumping the bucket every day or every other day.

Failure to dump the bucket will trip the unit and it will stop pulling the water out of the air until it’s dumped. So you’ll notice the trade-off here. There’s very little mechanical maintenance required for a dehumidifier, but there’s a frequent manual operation to drain the water out.


The last big difference between these two systems is their price. You can find a small dehumidifier for less than $50 in a lot of different stores. A small air purifier will cost closer to $150 or $200.


When it comes to more comfortable air in your home, there are a few choices. The most popular two are air purifiers and dehumidifiers. Both of these units will service the air in a very different way but will result in better air.

Air purifiers filter out all of the tiny dirt, debris, and dander in the air. They are great for pet owners, and they will help you breathe better in your home. There’s more mechanical maintenance and they cost more upfront, though.

Dehumidifiers work by sucking the water out of the air and filling up a bucket with the water. They are less expensive and require very little mechanical maintenance. They just need to be emptied pretty frequently. They will not filter out anything in your air, they just take the excess water out of your air.

Either option has its own merits, and either one could be useful for a homeowner. At the end of the day, which do you need more? Clean air, or dry air?