Are Air Purifiers Also Fans? Clearing Up A Common Question

If you’ve been around an air purifier before, you probably already know that most move air. And if they move air, it’s easy to see why you might wonder if air purifiers are also fans.

Not only will I answer this question but I’ll also show you how air purifiers work.

You’ll also find out a bit more about a few that actually do act like fans as well!

The basic question: are air purifiers also fans?

The general rule is “No.” Air purifiers aren’t fans alone. That is, while they do move and circulate air, most can’t do so with the high speed & larger airflow of a basic electric fan.

More importantly, they’re designed for cleaning the air you breathe which in turn makes a large impact on the airflow volume they can offer.

Standard electrical fans don’t have the same restrictions caused by doing other work like an air purifier does. Because of that, ordinary fans can blow air much faster to cool you and the room you’re in.

Read on and I’ll explain why they’re not fans.

First, let’s talk about what a fan is and then what an air purifier is. I’ll then compare the two and explain specifically how they’re different.

What is a fan and how does it move air?

centrifugal fan vs axial fan comparison diagram

Electrical fans come in different styles and serve different purposes. Both use an electric motor to rotate blades which cut through the air and cause it to move from one side to the other, creating airflow. Both centrifugal and axial style fans are used in air purifiers. You may have seen axial fans used in your desktop computer case. The curved blades on a fan cause the motion of air that is so important.

A fan is a device with fixed blades (usually curved) that force nearby air to move from the rear to the front of it in a blowing motion. It’s a common misconception that a fan cools air because it actually doesn’t. Instead, it moves air to create the opportunity for cooling by the evaporation of sweat and convection in an environment.

In other words, fans move a liquid or gas (air) rapidly to allow cooling to occur on you or an object.

Normally they’re powered by an electrical motor that uses many windings of copper wire to produce movement and turn the blades. This is done by allowing electric current to pass through the windings which then creates magnetic fields.

These fields, in turn, push away from other magnetic fields and the rotor, the rotating center section, turns. The fan blades, attached to the rotor, then cut through the surrounding air and the air is forced to move.

Typically the fastest fans have the greatest flow of air.

Evaporation

Sweating is how your body self-regulates its temperature. As your sweat evaporates, your body cools off because it requires heat to convert water to vapor. In still air, however, it isn’t so easy for sweat to evaporate. The air circulated by a fan helps the sweat on your skin to evaporate faster.

That’s why you feel cooler when there’s a fan blowing around you or on you.

Convection

Aside from helping regulate heat by helping your sweat to evaporate, fans also have a role to play in a process called convection. For our purposes, we’ll consider this process as heat moving away from one place to a cooler place. When you feel hot and the surrounding air is cooler, your body cools down by transferring heat to the air.

Air becomes less dense and rises at it’s heated. When you have a fan in the room, it helps to carry this warm air away. Cooler and denser air will settle down and the cycle continues, making you feel cooler.

Fans are generally designed to blow air as I mentioned above, although some fans are designed to suck or pull air. Some examples exhaust fans, vacuum cleaners, and range hoods (like you’ve seen in restaurants or perhaps in a home kitchen).

We’ll leave fans here for the moment and take a look at air purifiers.

What is an air purifier? How does an air purifier work?

diagram of how an air purifier works

Air purifiers work by moving air through filters and trapping airborne elements that cause pollution, allergies, asthma, sickness, and much more. Additionally, with an active carbon filter (a separate type of filter) they can trap odors and airborne chemicals. Some products like this GermGuardian AC4900CA also include a germ-killing feature using ultraviolet (UV) light.

An air purifier is an electrical device that eliminates airborne pollutants in a room.

Most air purifiers contain an electric fan which pulls air to the intake part of the device. Air is then forced through a series of replaceable filters where pollutants are trapped. After the air is cleaned it’s released back into the room.

As the process continues the air purifier will continuously cycle and filter bad elements and odors in a room. The result is fresh, clean, healthy air being left behind.

Air purifier filter types

Image of a GermGuardian AC4100 showing HEPA and activated carbon filtersA small air purifier (GermGuardian AC4100) showing the dense HEPA filter (white) and the activated carbon pre-filter (black). These work together to remove foreign particulates and substances like odors from the air. Neither can work alone to do both functions.

High-Efficiency Particulate Air (HEPA) filters are made of very thin entangled glass threads that are formed into a flat sheet, which is pleated like an accordion. Think of it as being an extremely dense material with gaps far too small to see with the human eye.

This material works to filter & trap 99.97% of airborne particulates and allergens as small as 0.3 microns (that’s 1/1,000,000 of a meter in size).

Activated carbon filters are often used along with HEPA filters because of their porous nature which makes them highly effective at absorbing volatile organic chemicals, odors, and some gases in the air. They may or may not be a part of an air purifier that you buy.

It depends on the design of the product.

Pre-filters are usually made of washable foam or nylon materials that trap larger particles. These are often integrated with HEPA and carbon filters so as not to overwork the more expensive filters. They’re typically a less dense and thinner filter serving mainly just to trap larger elements in the air like dust, insects, hair, and so on.

They’re generally used as a 1st stage in the filtering process if provided.

Aside from different filters used, there are also different types of air purifiers. Some use ultraviolet light (UV) rays to destroy mold, mildew, viruses, and other germs in the air as they pass by. There are also ozone-generators and negative-ion air purifiers that remove microbes and gases but produce ozone molecules as a functional by-product. Ozone-producing air purifiers are not approved by the Environmental Protection Agency (EPA).

So, are air purifiers also fans in a way?

AC4825 rear motor and fan illustration
Air purifiers contain electric fans which are used to draw in dirty air and blow out clean, filtered air. The pink arrows in the image point to the centrifugal fans used in this GermGuardian AC4825 purifier. In the center you can see the silver electric motor used to drive them both.

As I mentioned at the beginning of my post, it’s important to understand the difference between a regular fan and an air purifier.

1. Unlike fans, the majority of air purifiers have filters that greatly slow the flow of air through them.

That’s why they’re not capable of moving enough air to cool you or your room. The rate depends upon the purifier’s fan speed in use and efficiency.

These two products are not the same because they’re designed and made for different purposes.

The way they operate is different, too. They’re similar in the sense that both cause the air in your room to circulate. Fans circulate air in a room as a side effect of how they work – often they’re used to blow air directly.

Air purifiers, on the other hand, filter airborne particulates and circulate the air as they go through the dynamics of air purifying. Air circulation, rather than blowing air directly in any particular direction, is critical to how they function.

2. Most purifiers aren’t designed with fans that can move enough air to cool a room.

Purifiers aren’t expected to clean all the air in a room rapidly. It can take anywhere from several hours to a few days depending on the product and the room size. Air purification is a process that takes time.

If you require something that was much faster, it would be much larger in size and more expensive. That isn’t practical and very few people would be willing to pay for that.

There are also some types that don’t have fans. These products don’t add to the normal circulation of air in a room, and thus don’t have the added function of a fan. Ionizers and some ozone generators are good examples of this type.

Examples of air purifiers that are fans

Image of air purifiers that are fans
There are a few exceptions to the rule. A few products on the market actually do act as fans. The Honeywell AirGenius product family (left) and Dyson air purifiers like the Pure Cool purifying fan (right) create a very high airflow in a room much like a fan.

While what you’ve read is true for most, there are a few exceptions to the rule. Some products like the Dyson Pure Cool purifying fan are designed specifically to move large amounts of air to help keep you cool & comfortable.

Others like the Honeywell Air Genius 5 have a different type of filter design which allows a high rate of air to blow just as a fan (and even oscillates to blow air like a fan).

In conclusion

Most air purifiers are not, in the most strict sense, fans. They can’t move large amounts of air rapidly like fans and cannot cool you or your home. There are a few models, however, that are exceptions to this.

Unlike a fan, the typical air purifier:

  • Can’t produce high-speed airflow – the filters inside greatly reduce it
  • Won’t cool you or the room, as the airflow doesn’t extend very far past the purifier
  • Needs a lot of time to circulate the air in a room

As most air purifiers work, they do circulate the air in a room, which is the function of a fan. So in that respect, they do work as fans. But we draw the line there because an air purifier is more than just a fan.

If the ability to cool a room is important to you, plan on purchasing a fan separately. You can, in most cases, use a fan in the same room with an air purifier without any problems!

Hopefully I’ve cleared up the question for you and helped you better understand the differences.

Wondering if you can use a purifier with the windows open? Here’s a helpful post I wrote to answer the question about air purifiers and open windows.

Your comments are welcome!

  1. Hello, I want an air purifier for my daughters room, they have 3 fans in their room, will an air purifier work if the fans are on?

    Reply
    • Hello Lizzy. if the fans those such as box, pedestal, or ceiling fans, yes it’s fine. The fans will be moving air but the purifier will still be cycling & cleaning it.

      If they’re fans that vent air from outside, it will still work but will have to also clean that air, too. If it’s this case I’d leave the purifier running most of the time.

      Thanks!

      Reply
  2. We have a lot of dust on our site & no time to clean it in any significant way before an earthquake retrofit will be happpening. Even keeping our windows closed, a significant amount of far worse dust will be continually seeping in: Can yor recommend an air purifier that doesn’t move or blow the air around noticebly (… you mentioned some that don’t have fans?), –but is super effective at removing particles from the air, & ozone free, & not a humidifier? Thanx!

    Reply
    • Hi Diana. The ones that don’t have fans are usually ionizers or ozone generators and those really don’t do much. A HEPA purifier with a fan is the type that’s the most effective in most cases.

      If you get a good one like for medium or large-sized rooms (you should use an air purifier that’s recommended for a given room size) you can leave it on low or medium if you like to avoid high airflow output. The Winix 5500-2 (better odor filter) and 5300-2 are two very good ones. They helped me with fabric-type dust I had a problem with. They also have an auto-sensing operation feature.

      Most purifiers don’t disturb the air much unless they’re on their high or “turbo” fan setting anyway.

      Reply
  3. Hope I’m not asking too many questions? They all seem neccessary to understand for purchasing. Here is actually the most important one: Hiw do I tell if I have the required 120V mains required of many of these units? I don’t understand the explanations I found on the net: When I look in the door of my circuit breaker box, the label on the door says 120-240 volt: Dies that mean units will blow a circuit on some plugs, but not others? Times running out to get something delivered on time, so so appreciate if you could answer this one 1st, as i may seem simply get one now & hooe I can return it if not satisfied… But no point if not compatible power situation. Thank you!

    (EDITED FOR SPACE) I managed to find a friend who coukd answer the last one: 120V is standard for USA. But our circuir breaker goes off if we have both delangi(sp?) heater & microwave running. So I guess I am now limited to models that are powerful for a karge room, but energy-saver or advertised not to pull much voltage… The Levoit 133, or IQAir which could be delivered quickly, don’t seem to be that?

    Any comments on 003 micron UltraHepa filters? If they work, I’d prefer a unit that has this as well as the other features. Also, AirDoctor mentioned being sealed so only filtered air comes out of machine, rather than bad air leaking out. Are all good purifiers well sealed?

    Reply
    • Hey Diana although we chatted this weekend I’ll post a reply here in case others have the same questions.

      – It’s not the voltage but rather the current rating, usually something like “15A” (15 amps) and etc. American homes have a maximum power rating allowed by the electrical code for a given electrical power circuit (branch of wiring connected via a circuit breaker). It means that if a heater is drawing a ton of power, for example, on that same breaker (ex.: 1,500W – 1,800W heater) plugging in another item may cause it to trip and shut off power.

      – It also matters how the home or building was wired, because unfortunately they’ll run wire to other room outlets with another circuit that will be powering some other heavy power use appliances. Then using those outlets may trip more easily and shutoff power to other things you’re using (been through this myself).

      The good news is that many air purifiers use somewhere around 15-55W or so depending on the fan setting. But a model like the IQAir has a more powerful fan there and in this particular case can draw a lot more. So while it could trip a circuit breaker on the max setting, it’s a lot less likely when used on one of the lower 3 settings.

      – The model that offers much lower particle size filtering is nice, but not needed for most air quality problems. However, smoke is a different story because it can be especially bothersome due to carrying particles smaller in size sometimes than a standard HEPA filter can totally remove. So if that’s an issue and the additional cost isn’t prohibitive for you, I’d say it might be a good choice.

      – Good quality air purifiers usually have a tight fit around the filter so they’re sealed. The generic replacement filters often don’t even fit right, which means they aren’t sealed and don’t work well. You can see it sometimes in reviews for replacement filters where it turns out they don’t even fit as described which is absurd!

      Thanks!

      Reply
  4. Thank you so much, + great talking to you! We’ll see how it all works.

    I have a new topic question 😊 Do you know anything about water filters, especially the pitcher kind? Once again I’m finding really contradictory reviews on the net. My interest is a unit that offers the best filtration, all other features are of less value; though of course I want one that won’t break!

    Best filtration to me means removing all, or incredibly close to all:

    a. chlorine, lead, flouride, asbestos(& any other things that might nit be in most tap water but can be there because of old plumbing, or work that is being done on your building… by landlirds not concerned about the safety of there tenants), etc;

    b. Low TDS (I’m not confident that the level of radiation that gets in tap water is at safe levels; at least not for people who are already unhealthy).

    I’m not really concerned about bacteria or parasites, I know some get in tap water; but I believe the human body can work w/them far more than the above.

    A. Aquasana says it dies the most & specifically shiws all it covers that all others lack.

    B. Another review says Aquagear does.

    C. None of them remove all TDS like Zero Water… so I’m thinking of getting it along w/one other & fiktering thru both; then adding trace minreals, as i think the effect of drinking water w/everything removed could be very bad, unkess for short term energencies. Zero water i think breaks or leaks though, so ….?

    D. Most reviews, though they say Brita is #1 & highly certified, also say it doesn’t filter out most of the harmful that others do.

    E. Another says ClearlyFiltered does almost as much as A. & B.

    Can you -filter- out the facts, & let me kniw which really filters everything I want out best? 😀

    Thank you!

    Reply
  5. How about carbon monixide detectors? 🙂 We accidentally got one that is a plug in. We read about another plug in that has a backup 10 yr lithium battery, but i read bsd reviews of it not kicking in when power went out. Plus it says it won’t go off when its dark & wake you up… Yet that would seem the most important time.

    Anyways, can you recommend one that’s reliable, & is certified to satisfy the California state requirements & fire marshall(?) approval( these last 2 woukd be stated in the product info.

    Thank you!

    Reply
  6. This was good information. It’s going to be hot again in Seattle – have a purifier – was hoping it would work with my 90 yr old mother and myself. Thank you for being there

    Reply

Leave a Reply to Grant Williams Cancel reply