What's the Difference Between an Air Cleaner and Air Purifier?

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Whats the Difference Between an Air Cleaner and Air Purifier?

Between smog, exhaust, pollution, and countless allergens, breathing clean air has become a near-impossibility, particularly for those living in large, bustling cities. As a result, many people are turning to certain appliances that will clean the air inside their homes through particle removal. When looking for a way to clean the air inside a home, it is easy to become confused about terminology. For example, many people think that air purifiers are different than air cleaners. In reality, they are the same. The terms air purifier and air cleaner are completely interchangeable. By understanding what air purifiers are and how they work, it is easier to zero in on the right one.

Indoor Air Pollutants and Air Purifiers

Before looking for an indoor air purifier, or air cleaner, it helps to have a basic understanding of the types of air pollutants that are often found in homes. This knowledge makes it easier to find air cleaners and air purifiers that effectively clean the air. With a basic understanding of indoor air pollutants, it is easier to make sense of the descriptions of today's most popular air cleaners.

Volatile Organic Compounds

Volatile organic compounds, or VOCs, are gases or vapors emitted by many everyday household items. They may be emitted by things like new carpeting, paints, adhesives, varnishes, glues, and disinfectants. To determine whether a household product contains VOCs, look for ingredients like formaldehyde, toluene, chloride, ethylene, and benzene. Some air cleaners are designed to filter VOCs from the air, but others are not capable of doing so. If this is an important factor, look for air purifiers with filters that pull VOCs out of the air.

Odors and Gases

Some air cleaners can largely eliminate odors and gases from the air in a home. They do so with activated carbon filters, which are included on just about every air purifier and air cleaner on the market. These filters use a process called adsorption to force these gases and odors to become attached using a chemical reaction. Common gases and odors include aerosols, tobacco smoke, cooking odors, indoor pesticides, kitty litter, and toxins.

Airborne Particles

Most people buy air purifiers and air cleaners to eliminate airborne particles from their homes. Airborne particles include things like dust mites, pet dander, pollen, mold, plant spores, and fungi. These types of particles exacerbate conditions like asthma and allergies, so it is smart to eliminate them from the air inside a home. HEPA filters are considered to be the most effective in eliminating these particles, which can vary in size considerably but are all microscopic.

The size of the average airborne particle is measured in microns. One micron equals 1/25,000 of an inch. To be classified as a HEPA filter, a filter must be able to pull 99.97 percent of airborne particles that measure as small as 0.3 microns.

Particle Type



0.003 microns to 0.04 microns


0.3 microns to three microns


0.5 microns to five microns

Pet dander

0.3 microns to 100 microns


Two microns to 20 microns


10 microns to 100 microns

Dust mite

10 microns to 40 microns

Plant spore

10 microns to 70 microns


Some air purifiers are designed to pull microorganisms from the air. In some cases, air cleaners also kill microorganisms using UV rays and other techniques. Bacteria, viruses, pathogens, and antigens are all microorganisms. Mold falls into this category as well.

Types of Air Filters

Whether it is called an air purifier or an air cleaner, the most important components of this type of machine are its air filters. Indeed, most air purifiers and air cleaners contain at least two air filters. Some use three or four different air filters. One of the easiest ways to find the right air purifier is by looking for models that have specific types of filters. To do that, learn about the main characteristics of today's most popular air filters.

Activated Carbon Filters

This type of filter is not generally used alone. Instead, it is often used in conjunction with HEPA filters and other air filters. Activated carbon uses a chemical reaction called adsorption to pull odors, gases, and vapors from the air. The carbon that is found in these filters is treated with oxygen, which forces millions of small openings to develop. With an increased surface area, an activated carbon filter can pull odors, gases, and vapors from the air for a very long time. Some activated carbon filters can also pull VOCs from the air. They contain an extra chemical, which is known as a chemisorbent, which traps them in the filter or makes them harmless.

Ion and Ozone Generators

Although they are not technically filters, ion and ozone generators are designed to do the same thing: remove impurities from the air. However, instead of filtering them out, they just make them cling to surfaces around a room. These generators also often release ozone as a byproduct. This can be problematic because ozone is considered a lung irritant.

Electrostatic Precipitators

The same process that is used with ozone and ion generators is used with electrostatic precipitators. The primary difference is that an electrostatic precipitator actually filters impurities out of the air too. However, they can also produce ozone as a byproduct, so air purifiers that use this technology may not be suitable for people with respiratory conditions. The impurities are collected on plates that can be washed, so there is no need to buy replacement filters.

Charged Media Filters

The description of these filters is almost identical to those of electrostatic precipitators. The main difference is that these filters actually use filters instead of plates. As a result, it is necessary to change the filter from time to time. One of the best things about these filters is that they can trap extremely microscopic particles. Like electrostatic precipitators and ion and ozone generators, however, they also produce ozone.


If large particles are allowed to make contact with sensitive filters, air purifiers and air cleaners will not work as effectively or as efficiently. That is why the vast majority of these machines have pre-filters as well. A pre-filter's job is to pull larger particles from the air to keep them from being passed along to HEPA filters and other types of filters. They are typically made out of woven nylon or foam. In most cases, they can be cleaned again and again.

Antibacterial and Germicidal Filters

The only way to eliminate a huge percentage of germs and bacteria from the air is by purchasing an air purifier that includes antibacterial or germicidal filters. Sometimes, this technology involves the use of UV rays. Other times, HEPA filters are treated with specialized agents that kill bacteria, germs, and other microorganisms.

HEPA Filters

To successfully pull at least 99.97 percent of particles from the air, it is crucial to buy an air purifier that uses HEPA filters. High-efficiency particulate air filters, or HEPA filters, were originally designed to remove radioactive dust particles from the air. However, all HEPA filters are not created equal. The higher the area is, the more effective a HEPA filter is. Look at the square footage of the filter before buying an air purifier that uses HEPA technology. It is important to note that HEPA air purifiers do not remove gas and odor molecules from the air on their own, meaning another filter more effective for this purpose should be used either with or instead of a HEPA air filter.

Types of Air Cleaners

There are three main air cleaners, or air purifiers, available: whole-house air cleaners, whole-house air filters, and portable air purifiers.

Whole-house Air Cleaners

Whole-house air cleaners are installed directly into a home's heating and cooling system. However, this is not a job for an average homeowner. A professional must install this type of system. Also, a home has to have forced-air ducts in order to make one of these systems work. It should also be noted that whole-house air purifiers often need to be wired directly into a home's electrical system.

Whole-house Air Filters

An alternative way to clean a lot of the air in a home at one time is by using a whole-house air filter, which is designed to replace a standard furnace filter. This option is somewhat effective, but it does not eliminate nearly as many impurities as other types of air cleaners.

Portable Air Purifiers

Although one portable air purifier is only going to clean the air in one room, it is going to do so in a very effective way. There are many affordable room air purifiers out there, so many people place one in each room.

Pros and Cons of Different Air Purifiers

Type of Air Purifier or Air Cleaner



Whole-house air cleaner

Filters air throughout the entire home

Many options available


Has to be professionally installed

May have to be wired into home's electrical system

May not be as efficient as portable models

Whole-house air filter


Easy to use


Not very effective at purifying the air in a home

Filters must be compatible with furnace

Portable air purifier



May include casters or handles

Huge variety of options available

Options for every budget

Only cleans the air in a single room

Quality varies a lot from one model to the next

Air Purifier Features

Without understanding the main features of air purifiers and air cleaners, finding the right option is extremely difficult. Discover the differences between various air purifiers, and which features are most important before purchasing an air purifier or cleaner.

Energy Efficiency

The energy efficiency of an air purifier can be gauged by considering how many watts of power it uses. If wattage information is unavailable, simply multiply the number of volts by the number of amps. Options range from air cleaners that operate on around 50 watts, to models that run on 200 watts or more when on the highest setting.


The air changes per hour, or ACH, of an air purifier is an important characteristic. It reflects the number of times in an hour that an air cleaner exchanges the air in a room. The ACH is usually listed next to the room size. Stick with air purifiers with ACH ratings of four or higher, because they exchange the air at least four times per hour.


Consider an air purifier's clean air delivery rate, or CADR, before buying it as well. This rating is assigned by the Association of Home Appliance Manufacturers, or AHAM. The higher the CADR is, the more effective an air cleaner is at purifying the air.


MERV, or Minimum Efficiency Reporting Value, is a unit of measurement typically applied to whole-house air cleaners. Similar to CADR for portable air cleaners, MERV is intended to evaluate the performance of large air purifiers. A MERV rating typically registers between 1 and 16, and may even go as high as 20. The higher the number, the more effective the cleaner's air filtration is.


Energy Star

An Energy Star label on an air purifier means that the product has fulfilled the government standards for energy efficiency, saving consumers money while simultaneously reducing greenhouse gas emissions. Experts recommend purchasing a purifier that includes this symbol.

Filter Replacements

Prior to purchasing an air cleaner, check to see how often its filter or filters need to be changed. Also, find out the typical cost to replace each filter. Without doing this research, it is possible to spend hundreds of extra dollars per year on filters for an air purifier, which can ruin what looked like an otherwise good deal.

Finding Air Cleaners and Air Purifiers on eBay

In order to find air cleaners and purifiers on eBay, perform a simple keyword search. Type in "air cleaner" or "air purifier," then narrow the results by the type of purifier, such as HEPA or activated carbon, price range, brand, or condition. Alternately, type in a specific brand to get relevant results, such as "Honeywell air purifier" or "Holmes air purifier." Discuss the purifier with the seller before purchasing by contacting the seller directly from his or her member page, and read listings carefully to find out more about the purifier as well as shopping specials, such as free shipping. Always shop for air purifiers from Top-rated sellers who have excellent feedback from past purchasers.


Air purifiers and air cleaners are the same, but there are many style, cost and feature options available within this category. To find the right air cleaner or air purifier, learn more about how they work and about the types of air filters that they use.

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