Complete Air Purifier Buying Guide

Here’s a startling fact…

The United States Environmental Protection Agency discovered that the air quality inside our homes can actually be up to 5x more polluted than outdoors. The main culprits for this are the way buildings are constructed and the various things we bring indoors that release harmful contaminants.

If you combine that evidence with the fact that most Americans spend an average of 90% of their lives inside, you can understand why improving indoor air quality is now on so many people’s radar.

Fortunately, just because our homes are polluted doesn’t mean your health is doomed. There’s a simple solution for keeping the air you breathe inside clean and safe, and that’s by using an air purifier.

At their core, air purifiers work to remove harmful allergens, pollutants and toxins from the air so you don’t inhale them into your lungs. This act of cleaning the air helps ensure that you’re living the healthiest life possible while spending a predominate amount of your time indoors.

The only issue is that with so many options on the market today, trying to find the right air purifier for your home can be a frustrating task. To a lot of people, these machines seem complicated to understand and for good reasons too.

Practically every air purifier uses a different method to clean the air and this can make it difficult trying to choose the best one for your home.

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

This air purifier guide will explain everything you need to know about these devices.

Throughout this page, you’ll find out what air purifiers do, what types of pollutants they can remove, what key features to look out for, how to buy an air purifier for your specific needs, and more.

The table of contents section below outlines everything you’ll discover inside this free guide. Use it to jump to a particular section on this page or just keep scrolling to start from the beginning.

We hope you enjoy it!


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
    • Classic Version
    • Smart Enabled Version
  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?
  7. The Most Common Reasons for Getting an Air Purifier
    • Help with Allergies
    • Reduce Allergy Triggers
    • Prevent Dust
    • Eliminate Mold
    • Reduce Pet Dander and Hair
    • Remove Smoke and its Odor
  8. Additional Points to Consider
    • Maintenance Costs
    • Noise Level
    • Energy Consumption
    • Manufacturer Reputation
    • Warranty
  9. Frequently Asked Questions


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 of these bad particulates there are in the air, the lower the chance is that you’ll breathe them in. Without an air purifier, your lungs are the only filter for airborne contaminants which is why so many people get sick.

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.

How?

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 only breathe in clean, fresh air while indoors.

The bottom line is this: cleaner air = better health.

Air purifiers are known medically for reducing allergy symptoms, reducing asthma, improving sleep, making it easier to breathe and creating 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.

But, what exactly are those types of contaminants?

Below is a list of the most common pollutants that air purifiers target inside your home.

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

Every one of these pollutants are considered damaging to a person’s health, regardless if they have a specific allergy towards them or not. The only difference is that people who have a sensitivity to a particular contaminant notice the effects immediately, while others who don’t may end up with a serious health issue from long term (and untreated) exposure.

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 guide there many indoor particulates that air cleaners have been designed to eradicate.

However, not all air purifiers are made 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.

Before you start shopping for an air cleaner, consider some of the issues that you’re facing.

Do any of these sound familiar?

  • Are you experiencing seasonal allergy symptoms or ones related to pets?
  • Are things around the house causing your asthma to flare up but you can’t pinpoint the source?
  • Are you renovating a space and need to get rid of dust and/or paint fumes?
  • Are you prone to sickness or just want to sterilize your home by killing bacteria and viruses?
  • Do you have pets and want to get rid of dander, 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.

The next section will explain these filters in detail as well as the pros and cons of each one.

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 for sale.

Although the variety of choices can seem overwhelming, you’ll be happy to discover that there are really only four basic types of air filtration technology that these devices use.

These four air cleaning filters target different types of indoor air pollution and we’ll explain exactly how each one works.

1. 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 mechanism behind the top end machines.

There are several types of filters that use the HEPA acronym, but only one carries an actual certification you can trust. That label is 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 only 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.

Additional Info:

  • 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 routine filter replacements to maintain efficiency, usually the 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

2. Ionic Filtration

This air cleaning technology operates by emitting a cloud of charged ions into the air that latches onto airborne contaminants. This process forces these impurities to fall onto the floor and nearby surfaces.

Some ionic air purifiers include an electrostatic collection plate that attracts these fallen particles and removes them from the room. This process eliminates ultra-fine particles down to 0.01 microns in size.

Additional Info:

  • Pollutants it Can Remove: Dust, pollen, mold spores, fungi, volatile organic compounds, some bacteria and viruses, and visible smoke
  • Advantages: Practically maintenance free, doesn’t require costly filter replacements, less expensive than HEPA filter devices, doesn’t use a fan which makes it very quiet
  • Disadvantages: Pollutants remain in the room on the floor and surfaces unless collected on an electrostatic plate, collection plates require frequent cleaning with soap and water, doesn’t remove odors, produces small amounts of ozone as a byproduct which can irritate asthma and respiratory issues

3. 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 for trapping fumes, gases and odors.

Carbon filters are not used for removing particles that cause health issues, but rather get rid of the ones that cause smells. These filters are what makes a home smell fresh and clean.

Additional Info:

  • Pollutants in Can Remove: Chemical and gas fumes, odors and smells from pets, cooking, smoke, paints and cleaning supplies
  • Advantages: Relatively cheap to replace, helps a room smell fresh
  • Disadvantages: Only good for reducing gaseous fumes, smells and odors and not much else

4. Ultra Violet (UV) Light

Unlike the other three filters mentioned, this technology emits an invisible light that attacks pollutants as opposed to passing them through a physical filter. UV light is contained inside the air purifier and not released into the room.

Air purifiers with this technology 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 inside the home by destroying their molecular DNA structure. The end result is a sterilized, clean environment that’s free of particles which can make you sick.

Additional Info:

  • Pollutants it Can Remove: Bacteria, viruses and germs
  • Advantages: Ultra violet light lasts for thousands of hours and rarely needs replacement, creates a sterile environment, reduces the number of germs indoors that are responsible for creating illnesses
  • Disadvantages: Only good at killing viruses, bacteria and germs, cannot be bought as a stand alone device (always comes as an added bonus on a HEPA or Ionic air cleaner)

In addition to these four types of air filtration, air purifiers also come in two versions:

  • Classic Version
  • Smart Enabled Version

Simply put, classic air purifiers are the traditional model for these machines and don’t give you feedback on what impurities they’re actually removing from the air. You just have to trust how well they’re working by seeing how dirty the filter gets and by the claims made by the manufacturer.

Some classic air purifiers do have digital controls and air quality sensors to help them do their job more effectively. But, you never know exactly what contaminants the products has sensed and removed from your home.

On the other hand, smart enabled air purifiers come with a dedicated mobile app that gives you all sorts of data on how well the device is cleaning the air. Some apps reveal exactly which pollutants are being removed from the room (i.e. pollen or dust), as well as track air quality levels in real time.

With a smart enabled air purifier, you’re provided with a lot of additional information about your indoor environment and how effective the device is working. With a classic air purifier, you don’t get this luxury.

Keep in mind though that smart enabled technology does come at a cost. These versions of air purifiers usually cost $50-100 more than classic versions.

4. What are ACH and CADR Ratings?

When you’re looking to buy an air purifier you’ll sometimes come across two common ratings in the specifications list.

  • ACH
  • CADR

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 and 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 device can exchange the air within a room with clean, fresh air every hour.

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

A 4x rating means that the dirty air around in a space is removed and recycled with clean air four times per hour.

The higher the number, the more efficient the machine is at purifying the air inside 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. For now, just know that if a product has a 4x rating and specified to cover 300 sq. ft., this means that if you place the machine in a room that’s larger than this it won’t uphold the 4x exchange rate. It will be much less efficient and the air will not be as clean.

CADR Stands for “Clean Air Delivery Rate”

This rating was developed by the Association of Home Appliance Manufacturers (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 rating 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 a CADR rating on their list of specifications. Only manufacturers that have the AHAM independently test and certify their machine will display the CADR rating.

The major reason you want to look for the CADR rating is that 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 around the world as you might think and manufacturers could list a maximum square footage rating on their device that 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 get rid of certain types of indoor contaminants.

The CADR rating measures three types of air pollution:

  • Dust
  • Tobacco Smoke
  • Pollen

The measurement for each category can range anywhere between the numbers 10-450 and is displayed as a set of three numbers. For example, a CADR rating may be 200/220/190 where 200 refers to dust, 220 to tobacco smoke and 190 to pollen.

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 and include the CADR rating, those three numbers will clue you into which product is actually the better purchase for eliminating specific contaminants.

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

Air purifier size is another area that many consumers neglect to think about when shopping for a device.

If you really want to know how to buy an air purifier that’s the best for your home and health you’ll need to consider about this specification.

Most people think that an air purifier is a one size fits all type of machine, but it’s crucial to find out if it can actually handle the size of the room that it’s going to be placed in.

One of the worst things you can do is spend money on a new air purifier with the hopes of it solving your indoor air quality problems, only to discover that it doesn’t work as well as you thought.

To ensure that this doesn’t happen to you, all you have to do is check the square footage rating of the device that you’re interested in buying. Then, compare it to the size of the room that you want to use it in.

If the device has a square footage rating that’s equal to (=) or greater than (>) the intended room size, then it’s a good choice. If not, you’ll waste your money buying it.

Here’s how you properly size an air purifier for a room:

  • For a single room, measure the width and length of the space in feet and multiply these numbers together 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 total square footage numbers 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 (200 + 100 + 300) equals 600 sq. ft.

After doing these simple calculations, you’ll then know what the minimum square footage rating an air purifier must have in order to efficiently clean the air inside the room(s) of your home.

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 inside a room it won’t work as well as it was 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 a 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 airspace to work at maximum power.
  • Air cleaners that use Ionic filtration don’t operate by use of a fan, but rather emit ions in a 360-degree circle. This means that if you place the machine anywhere near a wall or piece of furniture, then you’re blocking its total output. The best placement for ionizers is near the center of a room.

6. What Types of Additional Features are Available on Air Purifiers?

This section of our air purifier buying guide describes the top things for what to look for in an air purifier.

What you’ll find when your comparing different air purifying machines is that they come with a variety of feature 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 may initially seem.

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

  • Pre-filter – This filter captures the largest particles (such as hair and dirt) and helps extend the life of the other internal filters. Pre-filters usually washable and reusable for the life of the product.
  • Digital Controls – These allow more precise settings for air quality control than 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 speed up the air cleaning process on demand.
  • Filter Replacement Indicators – These lights alert you to when it’s time to replace the filters within a machine when they’ve become too clogged with pollutants. Keeping a fresh air filter is the key to making sure that your machine cleans the air 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 – A handle gives you the option of easily transporting the machine between rooms without much hassle.
  • Casters – Similar to a carrying handle, casters are a set of wheels that allow you to roll heavier machines from room to room so you can enjoy the portability of an air purifier.
  • Antimicrobial Treatment – This coating prevents the build-up and spread of bacteria and microorganisms on internal filters, which increases the filter’s lifespan and prevents the reintroduction of 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 be 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 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 fungi.
  • Nightlight – Helps you to easily locate the air purifier inside a dark room and is convenient for a bedroom location.
  • Remote Control – This lets you control the machine from a distance.
  • Mobile App – This allows you to fully control every aspect of the air purifier from your mobile device. Some apps also include air quality monitoring data, so you can see in real-time how dirty or clean the air is inside your home.

7. The Most Common Reasons for Getting an Air Purifier

As you’ve discovered so far in this air purifier guide, these machines use a variety of filtering technologies to clean the air inside your home. These devices also include a wide range of features and options that make them more convenient to use.

Now, that may all sound good but what’s really the purpose for buying an air purifier? We’ll tackle that question next.

For the most part, there are really only six common reasons for why a person would want to use an air purifier in their home.

These reasons include:

1. To Help with Allergies

In the United States alone, an estimated 50 million people suffer from nasal and respiratory allergies. Airborne allergens wreak havoc on the immune system and cause many unpleasant symptoms like eye irritation, coughing, sneezing, painful headaches and more.

Our guide on the Top Air Purifier for Allergies reveals what the best products are for creating an allergen-free home.

2. To Reduce Asthma Triggers

More than 300 million people throughout the world suffer from asthma. This disease also accounts for about 14 million doctor visits each year.

The main contributor to asthma issues is breathing in polluted air. Air purifiers are one of the best ways to clean the air indoors so that asthmatics don’t experience as many respiratory issues.

If you have asthma, take a look at our guide on the Best HEPA Air Purifier for Asthma.

3. To Prevent Dust

No matter how hard you try to keep your home clean, dust always seems to accumulate on every surface. Dust also attracts dust mites, which many people are allergic to.

Air purifiers are an excellent way to cut down on dust and dust mites by sucking in and trapping these things before they ever have a chance to collect around your home. People who want to clean less often find air purifiers to be a great investment.

If this sounds like you, our guide on the Top Rated Air Purifiers for Dust is well worth the read.

4. To Eliminate Mold

It’s no surprise that mold spores are very harmful to your health. Unfortunately, many people have developed chronic illnesses from being exposed to too much mold while at home or work without even knowing it.

Specialized air purifiers made to combat mold and bacteria are the best way to make sure your stay healthy while inside.

If you have a concern like this, our exclusive guide on the Top Rated Air Purifiers for Mold will show you how to stay safe.

5. To Reduce Pet Dander and Hair

Around 30% of adults and 40% of children have nasal allergies and pet dander is a major culprit. Taking medication to fight pet allergies is not only a hassle but can also be quite expensive to keep up.

The other common problem with having indoor pets is the build-up of hair on furniture, rugs and other areas of the home. Fortunately, air purifiers are great for fixing both of these issues.

These devices collect and trap pet dander, which reduces related allergies, as well as the hair our pets shed.

To find out more about this common household condition, check out our guide on the Top Air Purifiers for Pet Allergies.

6. To Remove Smoke and its Odor

There’s a large percentage of the world’s population that smokes tobacco, which includes both cigarettes and cigars.

Some people who smoke don’t like how the odor lingers around inside their home and want a way to get rid of it. Others who don’t smoke themselves, but live with a smoker, also seek to find this same type of relief.

Air purifiers are the best solution for these types of concerns. These products are excellent at removing smoke and its odor from the air so that it smells fresh and clean no matter how often it’s smoked in.

If you’re looking for a device like this to use in your home, take a look at our guide on the Top Air Purifiers for Smoke and Odors.

8. Additional Points to Consider

When you’re making a decision on which air purifier to buy, there are a few additional points you may want to consider.

Being aware of these points below will help you get a product that meets your expectations in both air cleaning quality and cost to purchase the device.

Maintenance Costs

Air purifiers operate most efficiently when they’re properly maintained. Before purchasing an air purifying device for your home, make sure that you have a clear idea of how much it will cost you to keep it running smoothly.

Air purifiers that use a HEPA filter or carbon filter will require routine filter replacements. These types of filters trap particles inside them and eventually get clogged up and can’t clean the air anymore.

Filter life will depend on the amount of use and the air quality surrounding the unit. If you plan to buy an air purifier with a HEPA filter or carbon filter, check to see how often the manufacturer recommends for it to be replaced and how much replacement filters cost.

Filter lifespans can be anywhere from three months to one year. Filter costs range from $15 to $50.

If you purchase an ionic air cleaner you won’t have to worry about maintenance costs. That’s because these machines don’t use a degradable filter. Some ionizers do include a type of electrostatic collection filter to collect harmful particles from the air, but fortunately this filter is washable and reusable.

Ionic air purifiers are the least costly device to buy and maintain.

Noise Level

Air purifiers that use a HEPA filter or carbon filter to clean the air are always paired with a fan mechanism. This fan is what draws air into the unit and pushes it through these filters so that they can collect harmful particulates from the room.

As you already know, all fans produce noise.

Obviously, the slower the fan speed, the lower the noise level and the faster the fan speed, the louder it sounds.

Most air purifiers have at least two speeds (low and high) and some come with up to five speeds (low, medium, high, turbo and automatic).

Considering the noise level of an air purifier is important, especially if you’re going to use it in a bedroom or living room. This is one reason why you must get an air cleaner that’s properly sized for the room you want to use it in.

If the air purifier you buy is too small to handle the size of the room it’s placed in, then it will operate at higher speeds than normal to make up for the difference. This also means that it will always be on its loudest setting.

As we mentioned in the previous point, ionic air cleaners don’t use filters, which means they don’t use fans. Therefore, these types of air purifiers are practically silent when they operate. Noise is never an issue with these products.

Energy Consumption

Just like other home appliances, air purifiers require electrical energy to operate.

Since air purifying devices need to run continuously in order to keep the air clean and purified, you’ll want to consider the amount of energy a device uses before buying it.

Most air purifiers use between 5-200 watts of power. It’s best to find a device that carries the Energy Star rating, which ensures that it uses the least amount of energy possible and is the cheapest to operate.

Manufacturer Reputation

With the rate of air pollution around the world on the rise, it’s no surprise that air purification technology has become a dominant force in the global market.

There are now manufacturers all over the world that produce air purifying products for the home. Unfortunately, not all of these companies are creating high-quality machines.

When you’re buying an air purifier, it’s important for you to consider the reputation of the manufacturer for the device you want to buy.

There are a lot of companies out there that make bold claims about their products but are not 100% trustworthy. The reason for this is because not all countries have the same strict product regulations on air purifying machines like you see in the United States and Europe.

Therefore, a manufacturer not located in either of those areas may make statements about the level of air filtration that their product can handle, but hasn’t had it independently tested and verified.

Choosing a manufacturer that has a good reputation and provides top quality products is essential when making an investment in a home air purifying device.

A few companies you can trust include:

  • Alen Air
  • Austin Air
  • Blueair
  • Coway
  • Envion
  • Fellowes
  • GermGuardian
  • Hamilton Beach
  • Holmes
  • Honeywell
  • Mammoth
  • O-ION
  • Rabbit Air
  • Whirlpool
  • Winix

Any of the air purifiers produced by these manufacturers above will be a top-notch choice. Also, any marketing claims these companies make for a product are most likely accurate too.

Warranty

Before purchasing an air purifier, it’s recommended that you look at the manufacturer’s warranty. This can help avoid potential problems in the long run.

Find out what parts are covered and for what length of time, just in case they do become defective.

An air purifier is a long-term investment and is not something you want to keep replacing. You don’t want to buy a product that becomes faulty and then find out that the warranty didn’t cover the important mechanisms of the product or that it didn’t last for a reasonable period of time.

9. Frequently Asked Questions

Our air purifier buying guide wouldn’t be complete without a list of the most common questions people have about these products.

Take a look below to find out what the most frequently asked questions and their related answers are on air purifiers.

What kind of air purifier do I need?

The type of air purifier you need depends on the kind of contaminants that you want to get rid of and which are present inside your home.

To remove pollen, fungi, dust, mold spores, pet dander and visible smoke, you’ll want a HEPA air purifier or ionic air cleaner.

To remove gases, fumes, pet smells and smoke odors, you’ll want an air purifier with a carbon filter.

To kill viruses and bacteria, you’ll want an air cleaner with an ultra violet (UV-C) light.

How often does an air purifier need to run?

For the best air cleaning results, it’s advised to operate your air purifier continuously throughout the day.

At first, the device should be run on its highest setting or set to an automatic mode for it to adjust as needed to purify the room.

Once the air has been purified in the location, the device can run on its lowest setting and still maintain a clean airspace.

How much space can an air purifier cover?

Every air purifier is designed differently, therefore, some machines can handle large spaces, while others are made for small rooms. Check the maximum square footage rating in the device specifications sheet to find out what the suggested room size is for the best results.

How many air purifiers do I need?

Most people only need one or two air purifiers in their home. The ideal locations are to have one in the living room and/or bedroom since these are the areas that people spend the most time in and are often the most polluted.

Air purifiers are not designed to clean the air between two rooms that are separated by a door or wall. If you want to purify two connected spaces like this, you’ll need to use an individual air cleaner inside each room.

How do I know when to change an air purifier filter?

Some air purifiers include an air filter indicator light that alerts you when it’s time to change the filter. If your device doesn’t have this feature, check the product manual for the recommended time period for filter changes. It can be anywhere from three months to one year between a replacement is needed.

How difficult is it to change air purifier filters?

This process is often quite simple. Some air purifiers have a removal front face plate on the unit and the filter rests in a slot behind this location. Others feature a pullout filter on the side or back of the unit.

Neither type requires any special tools or repair skills. Check the product manual for exact instructions on replacing the filters.

Is it better to leave the windows open or closed when using an air purifier?

An air purifier needs a tightly sealed room in order to operate at maximum efficiency. Therefore, you need to keep the windows closed.

As the air purifier removes harmful contaminants from the air, the room becomes more purified and eventually becomes pollution free. If a window is left open, then the air inside the room can never be totally clean because the flow of exterior pollutants coming indoors never stops.

If a window is left open, then the air purifier will be overworked and strain will be put on the internal system.

I don’t live in a polluted city. Do I still need an air purifier?

According to the U.S. Environmental Protection Agency, the air quality indoors is 2-5x worse than outside no matter where you live.

Every time a window or door is opened, exterior pollutants like automobile exhaust, bacteria and allergens float indoors and get trapped inside our homes. Contaminants are also brought in on our clothing.

Additionally, there are many interior factors that lead to high levels of indoor air pollution, such as building and furniture materials, paints, cleaning agents, pet dander, mold and more.

Just because the area you live in may not be classified as a polluted place, doesn’t mean that the home you live in doesn’t have an air quality problem. An air purifier is a great investment for every home regardless of where you live.

How do I know if I have an indoor air quality problem?

Every home has some form of air quality issues. See the previous question and answer for details.

If you want to find out exactly what types of indoor air pollutants your residence has, there are various home testing kits available for this purpose.

Particle testing kits will help you identify contamination from radon gas, allergens, mold, formaldehyde, dust mites, fiberglass, volatile organic compounds and more. Pricing for these kits range between $50-200.

How efficient are air purifiers at cleaning the air?

Air purifiers can remove anywhere between 92-99.99% of harmful particles from the air that range in size from .01-3 microns.

The exact numbers for how efficient an air purifier depends on the type of air filtration and technology the device uses. Products will advertise the exact numbers for how good they are at cleaning the air.

Looking for More Questions and Answers About Air Purifiers?

Find out even more about air purifiers by visiting our page dedicated FAQ page: Every Question About Air Purifiers Answered in 50 Words or Less.

You’ll learn various ways on how to use an air purifier, how to find the best type for specific situations, answers to other buying questions and more.