8 Best Filterless Air Purifiers of 2021 Compared & Reviewed

Best Filterless Air Purifier
Photo: GreenTech

Filterless air purifiers remove unwanted particles from the air with no filter. This leads to improved efficiency, easier maintenance, and more energy-efficient devices.

You save money in the long term because there are no filters to change. Filterless air purifiers are also quieter and they kill the germs, making them more effective devices.

In this filterless air purifiers review, we offer you the following list of the market’s top offers, followed by a concise buying guide to help you make the right choice.

Types of Filterless Air Purifiers

Types of Filterless Air Purifiers
Photo: Airfree

1. Ozone Generator

Ozone is an oxidant gas, and this means it can break up other chemicals, such as smoke odors and so on.

An ozone generator intentionally creates ozone to fill the room, although many other purifier types create it by accident.

A good example is the Vivosun 2Pack air purifier set.

The problem with ozone is that it isn’t safe for humans, so it’s only safe in unoccupied rooms. And while the effects are minimal, its oxidizing effect can cause long-term degradation to different indoor materials.

2. Electrostatic Precipitation

This method of particle removal from the ambient air involves drawing in air, charging the particles in that air with either negative or positive ions, then attracting the charged particles with a plate that has an opposite charge, before releasing the air.

So, if the air is negatively charged, for example, then it will pass by a positively charged plate, which then magnets the particles carrying the charges, and cleaning the air. A good example is the Airfree T800 air purifier.

3. Ionizers

Ionizers are like electrostatic precipitators, in that they charge particles in the air.

But while electrostatic precipitation involves the drawing in, charging, and releasing of air, ionizers release the ions into the room and since they have no collector plates, the particles end up sticking all over your home.

4. Ultraviolet UV Cleaners

Ultraviolet Germicidal Irradiation or UVGI is another method that passes air through a chamber and then treats that air with a dose of ultraviolet rays, to destroy the DNA of the airborne microbes and eventually kill them.

This method can kill many micro-organisms, but a third-party certification of the device’s effectiveness is often necessary.

5. Thermodynamic Sterilization

Also called TSS, this means the use of heat to kill micro-organisms.

Here, the purifier’s core is heated to about 200° C (392° F) and the ambient air is passed through it, which results in the death of up to 99.9% of micro-organisms because of the high heat.

This air is subsequently cooled before being released back into the room.

Best Filterless Air Purifiers Buying Guide

How to Buy the Best Filterless Air Purifiers
Photo: Airfree

1. Coverage Area

Air purifiers come with a rating of the room size they can handle, and this is usually given in square feet. What you want here is a device with the same or a higher rating, so you are sure your filterless air purifier will work well.

If you are unsure about your space, then measure the length and the width, and multiply them to get the product. So, if your room measures 10 feet by 8 feet, for instance, then you’ll need an air purifier that’s rated for at least 80 square feet or higher.

2. Purifying Method

Another important feature of filterless air purifiers is their purification method because this helps to determine their effectiveness.

Ozone generators, for instance, are good in odor removal, while UV cleaners or thermodynamic sterilizers are more effective in killing micro-organisms.

The goal here, therefore, is to figure out what’s bothering you most and then get an air purifier that specifically targets such particles.

3. Energy Consumption

Depending on their purification method, the different filterless air purifiers out there use different levels of electric power.

So, if the electricity bill is an issue for you, then it might be worthwhile to look closer at each device’s energy-consumption rating.

4. Noise Level

Filterless air purifiers are silent units, so you’ve got nothing to worry about with ionizers and ozone generators.

You may, however, need to look closer with thermodynamic sterilizers and electrostatic precipitators, as they can feature fans that move air, and thus, make some noise.

5. Third-party Certifications

Manufacturers often make attractive claims to help sell their products, but many of the products don’t measure up to the claims.

The same goes for filterless air purifiers, so this means you must check and rely on 3rd-party certifications to confirm an air purifier’s advertised features.

8 Best Filterless Air Purifiers of 2021 Reviewed




GreenTech PureAir50

1. GreenTech PureAir50 (Best Overall)

  • Ionizer & ozone generator
  • Compact design
  • Low 3-watt consumption
  • Attractive price
Vivosun 2-Pack

2. Vivosun 2-Pack (Best Budget)

  • Low-priced offer
  • Pack of 2 units
  • Low power consumption
  • Simple instructions
Airfree Onix3000

3. Airfree Onix3000 (Best Premium)

  • Safe technology
  • Up to 650 square feet
  • Quiet operation
  • 2-year warranty
Clarifion GL-139

4. Clarifion GL-139 (Best Compact)

  • Compact & sleek
  • Lowest power consumption
  • Ideal for traveling
  • LED indicator light
Airfree T800

5. Airfree T800 (Best Thermodynamic)

  • Sleek & compact purifier
  • Thermodynamic TSS technology
  • Up to 180 square feet
  • Low & attractive price
IonPacific Ionbox

6. IonPacific Ionbox (Best Ionic)

  • Powerful ionizer
  • Up to 500 square feet
  • Dual-voltage power supply
Airfree Lotus

7. Airfree Lotus (100% Efficient)

  • 100% efficient air purifier
  • Up to 650 square feet
  • Silent operation
  • 2-year warranty
Airfree Tulip

8. Airfree Tulip (With Changing Lights)

  • Changing night light colors
  • Slim & beautiful
  • Up to 450 square feet
  • 2-year warranty

1. Best Overall: GreenTech PureAir50

GreenTech PureAir50

Photo: GreenTech

  • Coverage Area: 325 square feet
  • Cleaning Method: Ionizer, ozone generator
  • Power Consumption: 3 Watts

Combining an ionizer with an ozone generator, this GreenTech PureAir50 air purifier uses just 3 watts of power to remove bacteria, dust, odors, viruses, mold, and much more, while sticking compactly in an AC outlet. This makes it our overall best filterless air purifier on this list.

Its usage is simple. Plug it in and its ion generator gets to work. Then set its ozone generator level using the dial on the device and you’re all set. The ionizer magnets particles out of the air, while the ozone breaks down micro-organisms, giving you a double impact purification.

This air purifier also measures just 2.5 x 3.5 x 4.25 inches, and this makes it travel friendly. So, you can easily take it with you and plug it in your hotel room, office, or any other place you need fresh air.

You must watch out for its ozone generation though because while a high level of ozone (also known as activated oxygen) is very effective in purification, it remains toxic to humans. Fortunately, this unit comes with a dial to regulate its ozone levels.


  • Combines ionization with activated oxygen
  • Small and compact design
  • Uses just 3 Watts of electric power
  • Offered at an attractive price


  • A high concentration of ozone is toxic

2. Best Budget: Vivosun 2-Pack

Vivosun 2-Pack

Photo: Vivosun

  • Cleaning Method: Ozone generator
  • Power Consumption: < 7 Watts
  • Noise Level: 26 to 34 dB SPL

Designed for effective odor removal using ozone generation, this Vivosun air purifier also comes at a low and attractive price. Plus, its price is for a 2-pack set, making it our best budget offer.

Each of the purifiers plugs into an AC outlet and uses slightly less than 7 Watts of power. Just plug it in, adjust its ozone flow level, then leave the room, so it can do its job.

It measures 3.5 x 4 x 2.7 inches, so it’s compact and one of the best no-filter air purifiers for travels and other on-the-road uses. You can also adjust the efficiency between 10 and 50 mg of ozone per hour to get the right purification setting for your needs.

Its major issue is the toxicity of high ozone levels, so you need to follow the instructions and step out of the room while it’s working. Then everything is okay.


  • Low-priced ozone generator offer
  • The package contains 2 units
  • Low power and low noise
  • Backed by a 1-year manufacturer warranty


  • High ozone levels are toxic

3. Best Premium: Airfree Onix3000

Airfree Onix3000

Photo: Airfree

  • Coverage Area: 650 square feet
  • Cleaning Method: Thermodynamic TSS
  • Power Consumption: 51 Watts
  • Noise Level: Silent

Airfree designs the Onix3000 air purifier for passive germ-killing, using a unique and patented thermodynamic TSS core technology. This makes it a very safe and quiet unit, plus a highly effective premium design.

Thermodynamic sterilizers pass air through a core heated up to 400° F to kill the germs in the air. A passive TSS unit, such as this Onix3000 means there is no fan to pull in the air into the machine. Rather, air flows slowly through the machine based on convection principles.

Airfree designed this unit for spaces up to 650 square feet, and although it’s larger than the average ozone generator, it’s still a compact device that’s easy to pack into your luggage, placing it among the best air purifiers without filters in the market.

Its one downside is that it’s one of the costlier air purifiers. Thermodynamic purification uses relatively more power, but it’s also a safer air purification technology.


  • Works with safe thermodynamic technology
  • Designed for large spaces up to 650 square feet
  • Quiet design and technology
  • Backed by a 2-year warranty


  • It’s relatively power-hungry
  • Also relatively costly

4. Best Compact: Clarifion GL-139

Clarifion GL-139

Photo: Clarifion

  • Coverage Area: 54 square feet
  • Cleaning Method: Ion generation
  • Power Consumption: < 1 Watt
  • Noise Level: Silent

For those who prefer tiny footprints, this Clarifion air purifier offers the opportunity to own a compact device. It measures just 6.6 x 4 x 2.9 inches, which is hardly noticeable when sticking into an AC socket.

It’s also a very low-power device, rated at less than one watt. This makes it great for setups where you need not monitor the purifier because it hardly uses any power.

Based on ionization, this air purifier sends out partially charged ions into the air to stick to tiny particles, which then makes them stick to oppositely charged surfaces. It includes a LED indicator light to let you know it’s working, and it removes everything from odors to germs, smoke, and pet dander.

Its major disadvantage is its limit to 54-square-foot spaces, which means you’ll need extra units for larger spaces. It comes at a very low price though, so fewer worries.


  • Compact and sleek design
  • Very low power consumption
  • Ideal for traveling
  • Includes a LED indicator light


  • It’s limited to 54 square-foot areas

5. Best Thermodynamic: Airfree T800

Airfree T800

Photo: Airfree

  • Coverage Area: 180 square feet
  • Cleaning Method: Thermodynamic technology
  • Power Consumption: 42 Watts
  • Noise Level: Quiet

The Airfree T800 thermodynamic filterless purifier uses hot air to destroy airborne particles, such as mold, bacteria, pollens, dust mites, pet dander, and other organic micro-organisms. It works with the patented Thermodynamic TSS technology from Airfree at about 400° F.

This unit is additionally quiet, as there’s no electric motor to drive air through the machine. Rather, it uses natural convention to attract ambient air inside from its base and release clean air through the top.

Further features that make it our best filter-free air purifier with thermodynamic purification are its design and attractively low price. It’s relatively small at 5.1 x 5.1 x 12 inches while weighing only 1.5 pounds.

It doesn’t excel too well with power consumption, as it uses 42 Watts of power, which is way higher than that of the other technologies. However, in its defense, it’s a safer system, so it’s worth the extra cost.


  • Sleek and compact air purifier
  • Fully safe thermodynamic TSS technology
  • A silent operation
  • Offered at an attractive price


  • It has a relatively higher power consumption

6. Best Ionic: IonPacific Ionbox

IonPacific Ionbox

Photo: IonPacific

  • Coverage Area: 500 square feet
  • Cleaning Method: Ionic generation
  • Power Consumption: 1.5 Watts
  • Noise Level: 10 dB

IonPacific’s engineers took many years to create this super powerful ionizer that produces up to 20 million negative ions per second, making it able to completely saturate a 500-square meter space in under 30 minutes.

This impressive performance is enhanced by its very low consumption of only 1.5 Watts, placing it among the market’s best filterless air purifiers for efficiency.

It’s also a well-designed and compact unit, measuring only 6.1 x 4.4 x 2 inches and weighing only 4.8 ounces, so it’s easy to take along, anywhere. Then there’s the built-in dual-voltage design, so you need not worry about converters, and if you like, you could even power it from a USB port.

This is a top-of-the-line ionizer, and so it also comes at a top price, making it costlier than competing offers. It’s 5x higher than average ion generator, however, makes it worth it.


  • Produces up to 20 million ions per second
  • High-quality and efficient design
  • Rated for spaces up to 500 square feet
  • Dual-voltage power supply, including USB


  • It’s a relatively expensive ionizer

7. 100% Efficient TSS: Airfree Lotus

Airfree Lotus

Photo: Airfree

  • Coverage Area: 650 square feet
  • Cleaning Method: Thermodynamic technology
  • Power Consumption: 52 Watts
  • Noise Level: Silent

Featuring a distinct ‘Lotus’ design and a patented thermodynamic TSS technology, this Airfree Lotus air purifier also guarantees 100% efficiency in killing airborne micro-organisms from mold to bacteria, dust mites, and viruses.

Airfree rates it for rooms up to 650 square feet large and the entire filtration process is silent because it uses passive convection to draw air in, heat it to 400° F to kill everything, and then cool it down before releasing it back into the room.

This unit is also larger than most other Airfree thermodynamic purifiers, as it’s 13 inches high, with a 7.7-inch diameter, offering more space for its sterilization efficiency.

Two things, however, draw it down, and they are its power consumption and price, which are both the highest on this list. But then, that’s probably worth it when you need 100% efficiency.


  • A powerful air purifier with 100% efficiency
  • Rated for spaces up to 650 square feet
  • Silent operation
  • Backed by a 2-year warranty


  • It has a relatively high power consumption
  • It’s the costliest offer here

8. Best With Changing Night Light: Airfree Tulip

Airfree Tulip

Photo: Airfree

  • Coverage Area: 450 square feet
  • Cleaning Method: Thermodynamic sterilization
  • Power Consumption: 44 Watts
  • Noise Level: Silent

Airfree’s Tulip is another completely quiet and filterless thermodynamic sterilizer, but it’s slim, beautiful, and comes with a color-changing night light for a lovely ambiance.

It’s rated to cover up to 450 square feet, making it excellent for small areas, such as pantries, bathrooms, and bedrooms. This unit will destroy bacteria, fungi, pollen, dust mites, allergens, and nearly all other airborne micro-organisms.

If you’re the type that loves a stylish interior, then you might feel attracted to it, as it blends well with both modern and classic designs.

One issue, however, is that its passive convection depends on the natural airflow in a room, so it may not always produce optimal results. Adding an electric fan, however, could solve the problem.


  • Beautifully designed air purifier
  • Features a night light with changing colors
  • Rated for spaces up to 450 square feet
  • Comes with a 2-year warranty


  • Could be better with a fan


We’ve reached the end of this filterless air purifiers review, and you should hopefully have found a pick from our list above.

Otherwise, if you need a little help, then we recommend the GreenTech PureAir50 air purifier, as it’s a compact, effective, and cost-efficient unit.

But if you prefer an ionizer-only device, then we recommend the IonPacific IonBox, with its 500-square-foot coverage, 1.5-Watt low power consumption, and 10-dB silent operation.

And if it’s thermodynamic sterilization that catches your fancy, we recommend the Airfree T800 filterless air purifier, with its silent operation, attractive price, and 180-square foot reach.