Photo of Feature PanelAir purifiers come in all shapes and sizes and contain a lot of different options.

When comparing two air purifying products, it’s important that you know how each of the different features work.

That way you’ll be able to make a better-educated decision on which product is best for your needs.

In this guide, we’ll go over all of the various features and options you’ll find on air purifiers so you know how each one operates.


A pre-filter is used to capture the largest particles possible from the air. This feature is used to prolong the life of the main filter inside the air purifying device.

Since it traps large particles, it allows the main filter to work more diligently at capturing smaller particles like pollen, dust, pet dander, etc. without wearing out too fast.

HEPA Filter

A HEPA filter comes in two kinds:

  • True HEPA
  • HEPA-like or HEPA-type

A True HEPA filter is a super-dense filter that’s rated to capture 99.97% of particles as small as 0.3 microns.

This includes most pollen, dust, pet dander and other allergens.

A HEPA-like or HEPA-type filter doesn’t have any rated standard. It could capture particles as small as 5 microns or 2 microns.

You really don’t know unless the manufacturer tells you on the specifications sheet.

We highly recommend to always go with a True HEPA filter air purifier because you know it has been tested and rated to work in the most efficient manner possible.

This type of filter is the only kind that you’ll find on the best asthma air purifier models.

Ionic Generator

Products that go by the names, “Ionic air purifier,” “Air Ionizer,” or “Ionizer” all use an ionic generator to purify the air.

This technology works by emitting ions into the air that latch onto other particles in order to weigh them down and cause them to fall onto the ground.

This function prevents the particles from staying airborne and being inhaled into your lungs.

Some people do notice worse breathing problems due to the ions and ionic generator emits, like those who have asthma, while others never notice it’s running at all.

One company, in particular, Winix, uses a patented technology called “Plasmawave,” which operates similar to an ionic generator, but does not use harmful ozone.

It works by attacking pollutants at the molecular level to neutralize viruses, bacteria, and chemical vapors.

If you have asthma, you may want to consider an air purifier from Winix because it most likely won’t cause you any breathing problems.

If you don’t have asthma, then an ionizer is a great choice. Here are some of the best ionic air cleaner models.

UV Light

A UV light is a special type of technology that has been added to air purifiers in order to zap bacteria, germs, and viruses.

It works by destroying the DNA structure of the particles and causing them to be harmless to humans.

This is a great feature to look for on an air purifier because it helps create a sterile environment and rid it of harmful contaminants that can make you sick.

Carbon/Charcoal Filter

A carbon filter (also referred to as a charcoal filter), is used to get rid of odors inside a room.

This type of filter has a large surface area that is excellent at absorbing smells created by cooking, smoke, pets, chemicals and more.

Filter Change Indicator

If an air purifier contains a physical filter of any sort, it has to be changed on a regular basis in order for the device to work effectively. Unfortunately, filters don’t last forever.

But, how do you know when to change it? Do you do it once per month, every three months, bi-annually or on a yearly basis?

A filter change indicator takes the guesswork out of when to change the filter. Once the filter has lost its air purifying abilities, the indicator lights up to alert you that it needs to be changed.

Air Quality Sensors

Not all air purifiers monitor the air quality to determine how it should operate.

Some lower-priced products only include an on/off switch and a fan speed setting.

It’s up to you to determine if the air purifier should operate on low, high or turbo mode.

Air quality sensors are a good feature to have on an air purifying device because they constantly monitor the air for harmful particles.

Once bad toxins are identified, the machine adjusts the fan speed automatically to get rid of these contaminants in the fastest way possible.

As soon as the toxins are stripped from the air, the machine will go back to operating in a low mode.

This creates a hands-free operation for maintaining clean, fresh air.

AHAM Certification

The AHAM certification is only placed on products that have met or exceed a strict set of air purification standards. This seal was created to help consumers properly compare various products.

This certification is called a CADR rating and it focuses on three types of airborne contaminants:

  • Tobacco Smoke
  • Dust
  • Pollen

The CADR rating is displayed as a set of three numbers and tells you how well an air purifier is at reducing these specific types of particles. An example of this would be 150/200/180.

The higher the number, the better the product is at filtering the air for that type of particle.

Energy Star Label

The Energy Star label helps homeowners find household electronic products that have lower operating costs.

It also ensures higher energy efficiency and this helps protect our environment.

We recommend that you always look for this label when buying an air purifier.

Remote Control

All air purifiers can be controlled by buttons or knobs located on the device.

Some products offer a remote control feature so that you can control it from anywhere in the room.

This is a nice feature to have, especially if you have a wall-mounted unit.


Not all air purifiers are portable. Some products are meant to be set in one spot and kept there.

Others, include wheels or a handle that allow you to move the device to different rooms.

This is a great option for someone who wants to move the air purifier between various rooms in their house.

Fan Speed

All air purifiers contain at least two or more fan speeds.

The fan speed controls how fast the air purifier works at cleaning the air inside a room.

Lower priced products usually only have a low and high setting, while higher-priced devices can have low, medium, high and turbo modes.

Smart Phone App

Some newer air purifiers now offer apps, which lets you control the device wirelessly from the comfort of your own smartphone or tablet.

These apps also provide a lot of rich data about the air quality inside your home.

You can see what types of pollutants the air purifier is capturing, how often it senses them, air pollution history reports and more.

To find out more about this technology, check out this detailed smart air purifier guide.