Complete Air Purifier Buying Guide

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If you want to dramatically improve the air quality inside your home, an air purifier is the best product to get.

At their core, these devices work by removing harmful allergens, pollutants and toxins from the air so that you don’t breathe them into your lungs. This act of cleaning the air helps you live a healthier life, especially when you’re indoors.

Here’s a startling fact…

The United States Environmental Protection Agency discovered that the air quality inside our homes is actually up to 5x more polluted than outdoors. If you combine this with the fact that most Americans spend an average of 90% of their lives inside, you can see why improving indoor air quality is such an important concern.

However, if you landed on this page, then you’ve probably already realized that trying to find the right air purifier for your home can be a frustrating task.

To a lot of people, these machines seem complicated and hard to understand, and with so many different types of air cleaners in the market today it can be difficult trying to choose the best one.

It’s that very reason for why we put together this Complete Air Purifier Buying Guide.

Throughout this page, you’ll discover everything you need to know on how to buy an air purifier. You’ll find out what to look for in an air purifier, what these machines do, what types of pollutants they can remove, how you can find the right type for a particular need and more.

Air Purifier Buyers Guide Contents

  1. What are Air Purifiers?
    • What Types of Pollutants Can Air Purifiers Remove?
  2. Why Do You Need an Air Purifier?
  3. What are the Different Types of Air Purifiers?
    • HEPA Filtration
    • Ionic Filtration
    • Carbon Filtration
    • Ultra Violet Light
  4. What are ACH and CADR Ratings?
  5. How Do You Choose the Right Size Air Purifier?
    • Placement considerations
  6. What Types of Additional Features are Available?

1. What are Air Purifiers?

To put it simply, an air purifier cleans the air around you.

It does this through a specialized filtering process that targets microscopic particles that pose harm to your health. The less amount of these bad particulates there are in the air you breathe the better feel.

Without an air purifier, your lungs are the only filter for airborne contaminants.

If you suffer from allergies or asthma, or have a respiratory illness, you know firsthand how painful airborne irritants can be.

However, even if you don’t suffer from respiratory issues you can still notice a dramatic improvement in your health when using an air cleaner at home.


Because, a high quality air purifier can trap 99% of all air pollutants that would otherwise enter into your nasal passage and lungs. Pre-filtering the air in this way takes a lot of stress off of your lungs and ensures that you’re only breathing in clean, fresh air.

The bottom line is that cleaner air = better health, reduced allergies and asthma symptoms, easier breathing, improved sleep and an overall better standard of living.

What Types of Pollutants Can Air Purifiers Remove?

As you just learned, air purifiers are powerful machines that are designed to combat a wide variety of airborne pollutants. However, that you may now be wondering what exactly are those types of contaminants.

Below, is a list of the most common pollutants that air purifiers target.

  • Pollen, plant spores and fungi
  • Dust and dust mites
  • Pet dander and hair
  • Mold spores
  • Bacteria and viruses
  • Tobacco and wood smoke, and its odor
  • Household odors from cooking, pets and chemical cleaners
  • Gaseous toxins from aerosol sprays and pesticides
  • Volatile Organic Compounds (VOCs) found in paint, varnishes, cleaning supplies, new carpet and building materials

2. Why Do You Need an Air Purifier?

When you’re looking to buy an air purifying device, it’s important for you to focus on why you actually want it.

As you just saw in the first section of this air purifier buyers guide there are a large number of indoor particulates that air cleaners can eradicate. However, not all air purifiers are designed to get rid of every type of pollutant. We’ll explain this in more detail in the next section.

Therefore, determining what type of problem you’re trying to solve inside your home will help guide you on how to buy an air purifier that’s the right fit.

There are an air purifiers for all types of situations. As you’re shopping for an air cleaner consider the issues that you’re facing. Do any of these sound familiar?

  • Are you experiencing seasonal or pet related allergy symptoms?
  • Are invisible irritants causing your asthma to flare up?
  • Are you renovating a space and need to get rid of dust and/or paint fumes?
  • Are you prone to sickness and want to sterilize your home by killing bacteria and viruses?
  • Do you have pets and want to get rid of shedding hair and/or odors?
  • Do you want to get rid of tobacco smoke and/or its smell?

Let these types of questions be your guide.

Once you narrow down the main reason for getting an air purifying device, you’ll then know what air filtering type to look for and which to avoid.

3. What are the Different Types of Air Purifiers?

If you’ve done any type of browsing for an air purifier, you’ve undoubtedly noticed that there are hundreds of different types, styles and brands.

Although that can seem overwhelming you’ll be happy to find out that there are really only four basic types of air filtration technology that they use.

Different air cleaning filters target different types of air pollution and we’ll explain how each one works.

  • HEPA (High Efficiency Particulate Air) Filtration
    This air filtering process is considered the gold standard for air purification. It consists of a highly dense paper filter that traps airborne contaminants and is the driving force behind the top end machines. There are several types of filters that use the HEPA acronym, but only one carries an actual certification and is labeled as a “True HEPA Filter.” A True HEPA Filter is certified to remove 99.97% of all microscopic particles as small as 0.3 microns in size. Other filters that use the term “HEPA-type” or “HEPA-like” are inferior products and can 0nly capture particles as small as 2-5 microns. This equates to more than a 600% decrease in efficiency. When shopping for a HEPA air purifier, always look for the True HEPA designation.

    • Pollutants it Can Remove: Pollen, mold spores, fungi, dust, pet dander, hair, mold spores and visible smoke
    • Advantages: Highly efficient, traps particles and doesn’t release them back into the air, safe for all respiratory problems
    • Disadvantages: Requires regular replacement to maintain efficiency, usually most expensive type of air filtration, doesn’t remove odors or chemical fumes, uses a fan to pull in air and higher speeds can be noisy
  • Ionic Filtration
    This air cleaning technology operates by emitting a cloud of charged ions into the air that latch onto airborne contaminants. This process forces these impurities to fall onto the floor and/or nearby surfaces. Some ionic air purifiers include an electrostatic collection plate that attracts these fallen particles and removes them from the room. This process removes ultra-fine particles down to 0.01 microns in size.

    • Pollutants it Can Remove: Dust, pollen, mold spores, fungi, volatile organic compounds, some bacteria and viruses, and visible smoke
    • Advantages: Doesn’t require costly filter replacements, less expensive than HEPA filter devices, doesn’t use a fan making it very quiet
    • Disadvantages: Pollutants remain on the floor unless collected on electrostatic plate, collection plates require frequent cleaning, doesn’t remove odors, produce small amounts of ozone as a byproduct which can irritate asthma or respiratory issues
  • Carbon Filtration
    This type of air filter uses a special form of activated carbon that consists of millions of tiny absorbent pores. These pores create a large surface area that is excellent at trapping fumes, gases and odors.

    • Pollutants in Can Remove: Chemical fumes, gases, odors and smells
    • Advantages: Relatively cheap to replace, helps a room smell clean and fresh
    • Disadvantages: Only good for reducing gaseous fumes, smells and odors and not much else
  • Ultra Violet (UV) Light
    This technology emits an invisible light to attack pollutants as opposed to passing them through a physical filter. Air purifiers use the UV-C band of the ultra violet spectrum. This band is completely safe for humans and doesn’t cause any negative side effects. Its main purpose is to kill bacteria and viruses by destroying their molecular DNA structure.

    • Pollutants it Can Remove: Bacteria, viruses and germs
    • Advantages: Light lasts for thousands of hours and rarely needs replacement, creates a sterile environment, reduces the number of illness that can be spread inside a room
    • Disadvantages: Only good at killing germs and not much else, cannot be bought as a stand alone device (always comes as an added bonus on a HEPA or Ionic air cleaner)

4. What are ACH and CADR Ratings?

When you’re looking to buy an air purifier you’ll sometimes come across two different ratings in the list of specifications. Not all air cleaners have these ratings, but some do, so it’s good for you to know what they mean and how to compare two products that include these values.

ACH Stands for “Air Changes Per Hour”

This is one of the least understood ratings on air purifiers that often gets overlooked by consumers. However, it’s actually one of the most telling features about how efficient an air cleaner operates.

The ACH rating tells you how many times the machine can exchange the air within a room with fresh air every hour.

Common ratings you’ll see on a device are 4x, 5x, 6x, etc.

A 4x rating means that the air dirty air is removed and recycled with clean air four times per hour. The higher the number, the more efficient the machine is and purifying the air with a room.

It’s important to understand that this rating is directly tied to the maximum square footage the air purifier can handle. We’ll explain this in more detail in the next section on how to properly size an air cleaner for a room, but for now just know that if a product has a 4x rating and a 300 sq. ft. area specification, it means that if you place the machine in a larger room then it won’t uphold a 4x exchange rate.

CADR Stands for “Clean Air Delivery Rate”

This rating was developed by the Association of Home Appliance Manufactures (AHAM) as a way to help consumers know how well an air purifying device can clean the air within a particular size room.

The goal of the CADR rating is to give you an objective standard to compare the effectiveness of a device. This is especially important when you’re comparing two or more air purifiers against each other and trying to decide on which one to buy.

However, it’s important to point out that not all air cleaning devices include this rating on their list of specifications. Only manufacturers that that have the AHAM independently test and certify their machine will display the CADR rating.

The major reason you want to look for this rating is because it gives you an honest assessment of how large of a room the air purifying device can handle. Unfortunately, the air purifier market is not as regulated as you may think and manufacturers can list any maximum square footage rating on their device, which may or may not be 100% accurate.

The CADR rating ensures that if a product claims to purify a space up to 300 sq. ft., that it has been tested and verified to be true. It also tells you exactly how well the device can actually get rid of specific types of contaminants.

The CADR rating measures three types of air pollution:

  • Tobacco Smoke
  • Dust
  • Pollen

The measurement for each category can range anywhere between 10-450 CADR and is displayed as a set of three numbers. For example, 200/220/190.

The higher the number, the more effective the air cleaner is at removing that type of contaminant. When you’re comparing two or more air cleaners that have a similar square footage rating, the CADR numbers will clue you into which product is actually the better purchase.

5. How Do You Choose the Right Size Air Purifier?

Another aspect that’s consumers usually overlook when shopping for an air purifier is if the machine can actually handle the size of the room (or rooms) it’s going to be placed in.

One of the worst things you can do is spend money on a new air purifier, hoping that it’s going to solve all of your indoor air problems, only to discover that it doesn’t work as well as you thought.

To ensure that this situation doesn’t happen, all you have to do is check the square footage rating of the device you’re interested in buying and compare it to the space you want to use it. If the machine has a rating that’s equal to or greater than the space, then it’s a wise investment. If not, then you’re wasting your money purchasing it.

Here’s how put this step into practice:

  • For a single room, measure the width and length of the space in feet and multiple them by each other to get the total square footage.
    • For example, a 10′ x 20′ room = 200 sq. ft.
  • For multiple connected rooms, like a living room, dining room and kitchen, the only additional step you have to do is combine the totals from each space.
    • For example, a 10′ x 20′ living room = 200 sq. ft., a 10′ x 10′ dining room = 100 sq. ft., and a 15’x 20′ kitchen = 300 sq. ft. Combining these totals together equals 600 sq. ft.

Placement Considerations

This section of the air purifier buyers guide wouldn’t be complete without mentioning how important the placement of the device is to its overall effectiveness.

Sure, the product that you buy may have passed the square footage test, but if you put it in the wrong spot it won’t work as well as it has been designed.

Here are a few things for you to consider:

  • Air purifiers that use a HEPA filter and/or Carbon filter rely on a fan to pull dirty air into the unit and push clean air back into the room. Placing the machine under a table, behind a couch, against a wall or in any other place that blocks this stream of air flow will hinder its performance. The best placement for these types of air cleaners is 2-3 feet away from any wall or furniture. This will give the device enough surrounding air space to work at maximum power.
  • Air cleaners that uses Ionic filtration and/or an Ultra Violet Light don’t operate by use of a fan, but rather emit ions and radiation in a 360 degree circle. This means that if you place the machine anywhere near a wall or piece of furniture, then you’re reducing it’s total output. The best placement for ionizers or UV light outfitted purifiers is near the center of a room.

6. What Types of Additional Features are Available?

We’ve now come to the final section of this air purifier buying guide, and for many it’s the most exciting information to learn about what to look for in an air purifier.

What you’ll find when your looking at different air purifying machines is that they come with a variety of upgrades and options. Some of these features are worth the extra cost and can help sway your decision on which product to get, while others are not as important as they initially may seem.

Below, is a list of the most common features you’ll find on air cleaners.

  • Pre-filter – This filter captures the largest particles and helps extend the life of the other internal filters. Often this pre-filter is washable and reusable.
  • Digital Controls – Allows more precise and accurate settings as compared to a rotary dial or push button design
  • Adjustable Fan Speeds – Air purifiers can have anywhere between 2-5 fan speed settings, ranging from low to high and anywhere in between. Some even include a turbo speed to quicken the air cleaning process on demand.
  • Filter Replacement Indicator – These lights alert you to when it’s time to replace the filter within the machine so that it operates most effectively
  • Programmable Timer – This automatically shuts off the device after a specific time interval, such as 2, 4 or 8 hours. This feature helps save energy and keeps the device from running continually when you’re away from home.
  • Carrying Handle – Gives you the option of easily transporting the machine between rooms without much stress
  • Casters – Similar to a carrying handle, casters are set of wheels that allow you to roll heavier machines from room to room
  • Antimicrobial Treatment – Prevents the build up and spread of bacteria and microorganisms on internal filters, which increases the filter’s lifespan and prevents accidentally reintroducing these germs back into the air
  • Air Quality Sensors – These sensors monitor the air for specific pollutants and automatically adjust the air cleaner to the level it needs to quickly remove these particles
  • PlasmaWave Technology – An alternative and safer method of air ionization that doesn’t emit negative ions or produce ozone, but rather uses water vapor to achieve the same effect
  • Photocatalytic Oxidation (PCO) – An advanced filtering process that works in conjunction with an Ultra Violet Light to oxidize chemicals and destroy volatile organic compounds, bacteria, mold and fungus
  • Nightlight – Enables you to locate the air purifier inside a dark room and is convenient for a bedroom setting
  • Remote Control – Let’s you control the machine from a distance