Air Purifier – From A to Z:
The Complete Guide

Air Purifier
From A to Z:
The Complete Guide

Beginner’s Guide

Are you unsure about what makes a good air purifier?
In this guide we will give you the knowledge you need to breathe clean, fresh air.

Need help choosing the best air cleaner?

Check out our comparison table to help choose the best air purifier to buy for you.

Who is this guide for?

We wrote this guide for anyone looking to improve their indoor air quality. This applies to both your home and office. If you care most about air purifier performance and cleaner air, this is for you. Most of all, we want you to walk away confident you know how to solve your air quality issues. In some situations an air purifier is your best bet. In other cases there are other options that are better.

Who this is not for?

If you are looking for an air purifier only based on its looks, then this is not for you. Yes, we agree it should not look ugly. But we feel looks should not be the only criteria.

I was recently in Beijing looking at another brand’s air purifier at a shopping mall. The lady next to me commented to her husband that “this would make a nice decoration”. She didn’t care about performance, only about how it would look in her home.

Why we wrote this guide?

We wrote this guide to help you. Our goal is to help you breathe better and feel your best. As allergy and asthma sufferers we know what it is like to struggle and not feel well.

Bear with me while I first share my story. 16 years ago my son struggled with asthma. We did all the usual things like removing carpeting yet that did not help. His doctor prescribed a steroid that he breathed in with a nebulizer and mask. The medicine changed him. One change was his discoloured teeth and cavities.

The other was he would become angry and violent. I can’t tell you how many pairs of glasses were destroyed while I tried to hold him and keep the mask on. The experience was awful for everyone. It opened my eyes to the struggles so many face. This includes from allergies, asthma, COPD, pollution and a host of other respiratory allergy issues.

Enough said about me. Let’s get started and I hope you find this guide helpful.

Here is a summary for how we have structured this guide.


In this article we will cover:
1. Why you need to care about indoor air quality?
2. 3 strategies to improve indoor air
3. What is an air purifier?
4. How an air purifier works?
5. Types of air purification systems and how to choose the best air purifier?
6. What an air cleaner can and can’t do?
7. Why you need to care about indoor air quality?

The World Health Organization measures indoor and outdoor air pollution and reported more than 4 million people die each year from indoor air pollution. This number is more than from outdoor pollution. Granted, the majority of these cases are from Asia where people cook indoors. Although, it’s crazy to think that’s more than the entire population of Los Angeles.

Every year, in the US, studies based on air quality monitoring have shown indoor air is more dangerous than outdoor air pollution by 2-5 times. If you are smoking inside it can be 100 times. Why is this? There is not one answer but rather many reasons.

  • We spend 80%-90% of our time indoors.
  • We fixate on energy efficient homes.
  • Air conditioning costs often make up 50% or more of our energy bill so it makes sense to want to save.
    As a result, our homes are air tight.
  • The problem is the air inside becomes stale and more polluted since it is not ventilated.
  • We fixed one issue and created another.
  • Even in well ventilated places like an older apartment there are issues.
    Pollution or second hand smoke can come in from your neighbour or from a highway.
  • The same way pollen, mold and dust can pollute indoor air quality.
    Any airborne particle can easily move and that makes it challenging to live in a pure environment.

Common source of indoor air pollution:

  • Fumes from cleaning supplies, furniture, and carpeting (chemical gas)
  • Dust from the forced-air heating and air conditioning system
  • Our pets and dust mites create dander and other allergies as does dust pollen
  • High humidity, water and/or mold spores create mold and mildew
  • Smoking
  • Vehicle emissions near a highway or garage
  • Radon
  • Printers
  • Cooking
  • Gasoline, paint and other off-gassing chemicals
  • Not to mention pollen and other allergens that is brought in from the outside.

It seems allergies are getting worse every year; that is because they are. Indoor air not only impacts your life at home. Studies showed that business lose 6%-9% productivity due to poor indoor air quality. This may not sound like a lot but consider that 90% of an office buildings costs are for salaries. Here is how you can improve office productivity with clean air.

If you need to be at the top of your game and think well, it helps to work in an environment that is clean. I recall working in a large office building that had mold. Many of us would get headaches. It made it hard to work. Some developed migraines. We talk with customers every day who suffer from allergies and just want a good night’s sleep.

There are 3 proven strategies to improve your indoor air as stated by the EPA.

1. Source control
This means remove the source of the issue which is the best thing you can do. If you can completely remove the source you should not need an air purifier but unfortunately, this is not always possible or some people just don’t want to do this.

Let’s consider pet dander. If you want to remove pet dander then get rid of your pet. For most people this is not an option and we choose not to remove the source. In other cases it’s just not possible to remove the source. An example of this is pollen. We live in Austin, Texas and every winter the cedar trees give off an incredible amount of pollen. Many people suffer from what’s called cedar fever. It feels like you have the flu and to get rid of the source would mean removing every cedar tree for miles. It’s just not possible.

Another example is printers. The toner and ink in printers give off vapours and particulates. You are not going to stop using your printer because of this and we can go on and on. Often, it’s unlikely you can completely remove the source.

2. Ventilation

Another option is to improve ventilation in your home or work spaces. This is a good option if you have volatile organic compounds (VOC’s) or gases and they can originate from a number of places. By definition a volatile organic compound is an organic compound that can easily become a gas or vapour. Common indoor air pollutants come from cleaning supplies, furniture, or flooring. These materials off gas chemicals that in many cases is not good for you. Some like formaldehyde have been shown to cause cancer. Sadly, hazardous air pollutants are part of our everyday lives. Other examples of volatile organic compounds include vapours from paint and coatings. In a home your air conditioning system does not bring in fresh air from the outside. Rather it recirculates the indoor air. So, the only way to get fresh air is to open a door or window. The challenge is you may not want to do this if it’s hot or cold outside. If you have an energy efficient home or suffer from allergens you are likely not to keep your windows open. In an office building the air conditioning system is most likely bringing in air from the outside. The issue here is that sometimes it’s not enough air or in some cases building managers limits the use of the air handler to save on costs. This results in poor indoor air quality. Hotels present a whole host of other indoor air quality challenges.

A customer of ours who has a team of 30 programmers at a high end office park described his experience. The issue happened when it was pollen season and some of his top programmers were suffering from allergies. Some were not able to work well because the ventilation system only ran based on the temperature. So, when the temperature was mild, there was no ventilation. Temperature wise; it felt ok but the air quality was not good. They ended up installing several of our commercial units to clean and circulate the air. Since you are not removing the source, ventilation will help but is not a complete solution.

3. Air Cleaning

The third option is to use an air cleaner. As we stated above the best thing you can do is to remove the source of the issue. If this is not possible, air purification is your best bet.

An air purifier is a device that purifies the air of particulates or gases. There are a few different air purification technologies. We will present them in the form of the history as they have evolved over the past 70 years. High efficient air filters did not exist before the 1940’s. The US government was looking for a way to filter out harmful gases with a gas mask. What they invented later became the HEPA filter. The earliest air purifiers were respirators. These are face masks that are worn to filter the air. It would be a few more decades before air purifiers were used in homes. Respirators have air filtration standards and they are set by NIOSH (National Institute for Occupational Safety and Health). NIOSH has approved 7 classes of filters:

  • N95: Filters at least 95% of particles
  • N99: Filters at least 99% of particles
  • N100: Filters at least 99.97% of particles
  • R95: Filters at least 95% of particles and is somewhat resistant to oil
  • P95: Filters at least 95% of particles and resistant to oil
  • P99: Filters at least 99% of particles and resistant to oil
  • P100: Filters at least 99.97% of particles and resistant to oil

This standard is important since it gives you an idea for how well the filters perform. As you may know we also sell our air purifiers in China. When I was there, I have started to wear a N95 mask on the heavy pollution days as do about half of the people. What I have found is that when I walk by people smoking I can smell the smoke through the mask. I can also smell the air pollution. This made me question how well it removed the fine particles and gases.

The reality is, not well. The reason is because fine particles and gases are too small to be removed by a filter that only removes 95% which sounds like a good number but it just filters out the large particles. A good way to think about air purifiers is to compare them to masks. An issue with masks is that to be effective you need a good seal so you are not breathing in unfiltered air. This happens when the mask does not fit your face well. The same principle applies to air purifiers. If the seal is not good it is just recirculating the air.

Another issue with masks is that the higher the efficiency the harder it is to breathe through the mask. The more a filter can remove the harder it is to move air through it. It’s just more restrictive. A higher efficiency filter means more of the smaller sized particles are removed. This is important. It just takes more energy to move the air through it. For an air purifier, this means you need a stronger motor and fan to be able to power the air through a better filter.

Based on the principles of the masks, home air purifiers with filters were invented to clean rooms. They first started to show up about 25 years ago with a HEPA filter. So, this leads to our next topic.

How an air purifier works?

An air purifier is made up of a filter, motor/fan and housing. All have these 3 components. An air purifier circulates the air in a room and captures the particles and gases in the filters. For an air purifier to work well it needs to move enough air and it needs to have high efficiency filters.

Before we talk about filters we need to look at what is in the air. It’s made up of gases and particles. Gases are the smallest and most challenging to remove. Odours are gases. You may think of particles as the pollen or dust you see in the air. What you can see are the largest of the particles and generally they do not present a problem. This is because your nasal passages will filter them out. This is our built in filtering system. Also, the larger particles will drop to the ground and unlikely to be breathed in. The particles that cause the most trouble are the smallest ones. This is because they stay suspended in the air the longest and can be breathed into our lungs. They are not filtered by our nasal passages.

So, how do you know if the air purifier is working?

If you care about performance there are ways to know what you are getting. Let’s start with the filters.

Filters work with different principles to clean the air. A HEPA filter captures particles as they pass through the filter. Think of it as weaved fibre like in our clothes. But a much tighter weaves. HEPA stands for High Efficiency Particulate Air. In other words, it is a high efficiency filter for particulates from the air. The performance of a HEPA filter can vary a lot. This is due to the quality of the fibre material, the amount of filter media and the tightness of the weave. Most air purifiers say they have a HEPA filter and what they mean is they have a pleated filter. Like the NIOSH mask filters, air filters have a rating scale. It is called MERV and based on its ratings; you can see the efficiency of the filter. This lets you know how well it will remove the smallest of particles. At the top end of the scale is the ULPA (Ultra-Low Particulate Air). By definition an ULPA filter removes 99.999% of airborne particles with a size of 0.1 microns or larger. This level of air filtration is seen in a clean room or high-end bio-safety cabinet. If you want to know the performance over time there is a standard called CCM. This is related to the amount of filter media and the construction of the filter.

In general, the more filter media you have and the larger it is, the longer it will last. Smaller filters clog faster so you will see a faster drop in performance.

There are usually two types of material used in air filters. One is glass fibre (fiberglass). The other is synthetic fibres. The glass fibre material is often used in industrial filters. We use it in our Erik filters. It can achieve higher efficiencies than a true HEPA filter (99.97%). Glass fibre filters tend to have more filter media and a higher pressure drop (ie more air flow resistance).

Nonwoven synthetic is a newer technology that is more durable and common in consumer filters. We use this to make our consumer filters lighter such as in the EJ and Max room air purifiers. We also charge the filter media so it can achieve higher efficiency levels without a higher pressure drop.

In our product line the OV200 and Max v-HEPA Air Purifier are MERV16. The EJ120 is MERV17 and Erik650A is MERV18. The ERIK650A is the best HEPA air cleaner we make. Better than a genuine true HEPA filter.

We refer to them as HEPA air cleaners, however it’s more accurate to compare based on the filter rating. Some HEPA air purifiers also have a gas filter. This is usually an activated carbon filter for general gas and odour removal. For gases like formaldehyde, you should make sure other media is included. For this you will often see potassium permanganate.

HEPA is so popular because it works the best. It has the highest efficiencies. It also is the safest as it does
not create pollution like ozone.

Having a high efficiency filter and one that lasts without a drop in performance is great. But you also need to move the air. The CADR rating is way to measure the filtered air flow. This was developed by AHAM (Association of Home Appliance Manufacturers) as the industry standard.

AHAM is a leader in setting the air purifier standards in the US. They have a program called AHAM Verifide. The purpose of the program is to help consumers know what they are buying. They do this by secretly testing air purifiers from brands that are in the program. Air purifiers are tested at the Intertek air purifier lab in Cortland, NY under strict guidelines. The Clean Air Delivery Rate results are reported on the AHAM web site. This way you know exactly what you are getting.

Oransi is a member of the AHAM Verifide program. Sadly, some heavily marketed brands do not participate so it’s unclear what their performance is since they are not tested to the standard.

An organization that is a leader in filter testing is IBR Laboratories. IBR tested the HEPA filter media in our EJ and ERIK650A air cleaners with the results of 99.996% efficiency at 0.3 micron particle size. From what we can tell Consumer Reports does their own air purifier reviews and testing. Their test methodology is consistent with the AHAM CADR. Stiftung Warentest is a German consumer organization similar to Consumer Reports that does unbiased ratings and comparisons of consumer goods. It is interesting that Stiftung Warentest uses a German grade school scoring type system so a low score is best. Our understanding is Consumer Digest does not have their own test lab and leverage testing done by others.

Consumer Search and Apartment Therapy display their ratings of the best air purifier (or best buys) and they also refer to testing done by others with their own commentary.

The advantage of the CADR ratings for air purifiers is you know the products have been tested in a certified test lab to the industry standard and done under strict controls. They also help manage the Energy Star program. So, you know you are buying an energy efficient product. It’s a great starting point.

While the CADR is a good metric in our opinion it is not a great metric. It’s good in that it represents the filtered air flow so you know it can clean a certain sized room. The problem is it does not measure the filter performance over time. It also is only based on removing particles sized 0.3 microns and larger. This represents dust and larger particulates. It does not measure the smaller particles and gases. These smaller particulates make up 90% of all particulates and cause most health issues. So, if you have the best HEPA air filter you are at a disadvantage since you remove the smallest particles, yet they are not part of the test.

The use of higher efficient filters adds air flow resistance so the air flow will be lower than an air filter with lower efficiency. We know this going in and to provide you with the best air filters without sacrificing air flow, we make our filters larger and use top notch motors.

It’s hard to know how much square footage an air purifier can clean. We put together this handy guide so you can see how many square feet of coverage to expect for a given CADR. Most air purifiers on the market just give a room coverage number but fail to give you all of the information to know exactly what to expect.

The numbers below the Air Changes per Hour columns show the square footage for each CADR rating. In addition, we include the corresponding Oransi air purifiers so you can see how they compare.

Air Changes per Hour
CADR 1 2 3 4 Oransi Model
100 750 375 250 188  
150 1125 563 375 250 OV200
200 1500 750 500 375  
250 1875 938 625 469 Max
300 2250 1125 750 563  
350 2625 1313 875 656  
384 2880 1440 960 720 EJ
450 3375 1688 1125 844 Erik

So, how did we get to the CADR? Let me share a story.
In the 1990’s a company called The Sharper Image introduced the Ionic Breeze. This was marketed as a filter-less air purifier that cleaned the air and removed odours. And it was silent. They became the top air purifier brand.

The problem was it did not work as advertised and they went out of business. The reason it removed odours so well was because it produced ozone. Ozone is great at removing odours but is bad for your lungs.

The Sharper Image Ionic Breeze was silent because there was no motor or fan. So it moved almost no air. There was no way for it circulates the air in a room. It seemed too good to be true, and it was. The problem with the Ionic Breeze tower air purifier is that it did not do what they claimed. But worse, it introduced pollution in the form of ozone, a known lung irritant. This is not what you want in a room air cleaner.

As a result of concerns over the ozone, new standards were created for the state of California. Now, for any air purifier to be sold in California it has to certify that it does not produce excess ozone. Since the state of California is so large, it has influenced the national market.

What we have covered above is how a HEPA filter removes particles. For many, gas removal is also wanted. This can be for odours, chemicals, VOC’s, formaldehyde, pollution, natural gas and others. The challenge with a HEPA filter is that the gases are so small they pass right through. What works is to absorb them through a different type of filter.

The most common is carbon. In its raw form carbon does not do much. Yet, when baked in an oven carbon becomes activated. This activated carbon has many cracks and crevices that allow it to adsorb gases. This is similar to burning wood over a fire. You may wonder how to activate carbon for an air purifier. Well, it is cooked under precise conditions so the cracks are properly formed with the right amount of hardness.

Many air cleaners with carbon are promoted to remove smells. Yet, all carbons are not created equally. Some purifiers have a carbon pre-filter. Commonly this is a foam filter with a sprayed-on carbon coating. While better than nothing, the effectiveness is limited.

A better option is to use granular activated carbon; also known as GAC. Granular carbon if of high quality and sufficient amount can work well in the removal of things like tobacco smoke odours. GAC means the carbon is in pellet form and for it to work well, you want at least 3 pounds. This is precisely what we do with the carbon pre-filter in the EJ and ERIK650A air purifiers. They both have more than 3 pounds of specially treated activated carbon. This gives you the benefits of activated carbon plus other media to remove what carbon can’t.

There are two main reasons you should replace the filters. One is that if the filter is clogged the air flow will be reduced. This means you are not getting filtered air changes. This also applies to your furnace filters. I hate replacing these filters but there is a higher cost in using an old filter. A dirty filter causes your furnace system to run longer and harder. This results in higher energy bills and it adds to the wear and tear of the system. It’s cheaper just to replace the filter.

Another reason is that carbon filters have a life span. While carbon is great for adsorbing many gases it only does this while it has capacity. Guess what happens when you use this filter for much too long? At some point it will release the gases it is holding. This can show up as a rotten egg smell and should be avoided.

Now we will review the types of air purifiers that are available.

HEPA Air Purifier
The most popular type of air purifier is the HEPA air purifier. As we stated when a product says it has a HEPA filter it usually means it is a pleated air purifier filter. It often does not reflect the performance of the filter. You can determine this with the MERV rating.

A true HEPA filter has an efficiency of 99.97% or better in removing particles that sized at 0.3 microns and larger. We recognize this is a meaningless metric for most people. The MERV ratings scale in our opinion is a better way to compare true HEPA filters. The higher the number, the higher the efficiency the filter will be. The problem is most air purifiers, air filters just state true HEPA, HEPA-type filter or some other word combined with HEPA. This gives you no indication for the quality of the filter. And sadly most do not provide the MERV rating

In our product line the OV200 and Max v-HEPA Air Purifier are MERV16. The EJ120 is MERV17 and Erik650A is MERV18. The ERIK650A is the best HEPA air cleaner we make. Better than a genuine true HEPA filter.

We refer to them as HEPA air cleaners, however it’s more accurate to compare based on the filter rating. Some HEPA air purifiers also have a gas filter. This is usually an activated carbon filter for general gas and odour removal. For gases like formaldehyde, you should make sure other media is included. For this you will often see potassium permanganate.

HEPA is so popular because it works the best. It has the highest efficiencies. It also is the safest as it does not create pollution like ozone.

Many people who come to us are looking for allergy relief. We get it. We suffer from allergies too. Allergies can be from a variety of sources. To find an air purifier that works for allergies you should look at the effectiveness of the HEPA filter and motor quality. This is because allergens are airborne particulates. A HEPA filter is the best way to remove allergy particles from your air.

The way it works is that the large airborne particles are caught by a pre-filter. This includes things like large dust, pollen, pet hair, or pet dander. When a pre-filter is used it protects the HEPA filter from being clogged so easily. This extends the life of the HEPA filter. And it enables the HEPA filter to focus on the smallest airborne particulates. This is what you are buying the air purifier to do.

The motor quality is important so you can ensure there is enough filtered air flow. A cheap motor will not move enough air to clean your room. Or it may produce a lot of noise. Since we use our own products we know noise level is important. We design our air cleaners to use the highest quality motors available. In the case of the EJ and Erik series, we use German motors that are unmatched in quality, reliability and performance.

Unless you need odour removal a carbon filter is not going to be necessary. A carbon filter is a nice feature and can make your room smell better. It just may not contribute to allergy relief.

The other consideration is room size. If you have a small room you can get by with a lower air flow. We think of small rooms as 300 sqft or less. With air purifiers you often get what you pay for so a unit with a stronger air flow will filter your air more. This gives you a cleaner environment. If you have a large room such as more than 500 square feet, you will need a very strong motor. An air purifier with a small filter is not going to work well. You also need a really good motor.

Another tip is to place the air purifier in the room where you spend most of your time. Often this will be the bedroom and operate it on a fan speed that you can tolerate. All HEPA air purifiers produce a white noise. The noise level is related to the quality of the motor and the resistance of the filter.

Dust is a common problem. It’s interesting because dust takes a variety of forms. For many people, dust shows up when the forced-air heating or air conditioning system is turned on. The system is either old or dirty and this dust is spewed throughout your home. Another source of dust is from dust mites.

As with allergies, dust is hard to remove. Our first strategy is source control but dust is everywhere. It’s impossible to completely remove. If you have household dust we suggest you keep your home as clean as possible. The trick is to avoid contact with the dust. So, get a good HEPA vacuum cleaner and have someone who does not react to the dust do the cleaning. You do not want to be around with the dust is being removed. When it is kicked up the amount increases and that is not a place you want to be.

An air purifier for dust is your best bet to provide relief in your home or office. Since dust is a particulate you should focus on a high quality HEPA filter. You will also want to look at the motor and air flow to make sure it can clean your room size. You may think of dust as a larger particle but it is the finer dust that creates issues for us. The larger dust will settle to the ground and be removed by vacuuming. The smaller dust particles can stay suspended in the air for hours or days. This is what you breathe in. It’s what creates the problems for you. The better the HEPA filter the more of these small dust particles can be removed from your air. You will want a high efficiency filter.

The reason we started this business was to help those who suffer with respiratory issues, especially asthma. There are many asthma triggers and the key is to get rid of them. Here are some things you can do to help with asthma:

  •  Consult a doctor to ensure your condition is evaluated.
  •  Keep your home clean of allergy triggers. Consider removing carpeting or anything like draperies
    that hold in dust.
  • Keep your humidity levels between 35%-50%. This will reduce mold growth. And help with dust
  • Clean with a HEPA vacuum cleaner. Wear a mask to keep from inhaling the particles that are kicked
  • Reduce outdoor activity on high pollen days and when ozone levels are higher.
  • Use a HEPA air purifier

For someone with asthma especially with younger ones, you will want to go with a home air purifier that has a high efficiency filter at the least HEPA level – MERV 17. You will also want to make sure the motor is strong enough to circulate the air in your room 3-4 times per hour. The goal is to turn your room into a clean room.

Mold and mildew is a problem for many people. Besides an air purifier you may want to consider a dehumidifier to clean the air. Mold needs moisture to grow. A great way to control the humidity level is with an air conditioner or dehumidifier. The only issue with an AC is that it only runs based on the temperature in your room. A dehumidifier keys in on the humidity level and that is what is important.

A dehumidifier or AC will not remove the small mold spores from the air that cause health issues. They will also not remove odours. You need an air purifier for this.

Like with allergies you will want a high efficient HEPA filter to remove the small mold spores. Cheaper filters will only collect the large dust in your room. HEPA filtration units can remove mold particles big and small. If you need odour removal then should also have an activated carbon filter. This carbon is great for a wide range of gases including mold related odours. If you are looking to remove other gases like formaldehyde then you will need more than carbon. We would suggest a specialized gas filter like our EJ120 or Erik650A.

With smoke in a home the air quality can be 100 times more polluted than outdoor air. It is a health concern for everyone inside. We talk to a lot of people about tobacco smoke removal and many think about only the smoke odour. It’s more complicated than that.

Removing cigarette smoke smell is challenging since it is made up of small particles and hundreds of gases. To remove smoke you need to capture both. And when embedded into fabrics and carpeting can be almost impossible to completely remove. To get rid of the fine particulates requires a high efficiency HEPA filter.

You also need a strong carbon filter. Activated carbon does a good job in adsorbing smoke gases and odours. The problem with only having a HEPA filter is the smoke odour will not be removed. In some cases, the HEPA filter can capture the smoke odour and then re-release it later. You don’t want this.

In looking at our air purifiers, the best air purifiers for smoke removal are the EJ120 and Erik650A series. This is because they have the right amount of activated carbon and true HEPA filtration. The Max v-HEPA air purifier has a good HEPA filter, but frankly the carbon filter while good for light odours is not made to remove the tricky tobacco smoke odours.

When my son struggled with asthma we knew the pets could be contributing to his breathing issues. As we consider them family members we did not want to get rid of them. So, we understand the challenges you face with pet dander. We often hear about pet dander from dogs and cats but birds also present issues.

For the removal of pet dander and pet hair you will want a high efficient HEPA filter. If you have a lot of pet hair you will want a larger HEPA filter. Otherwise the filter could get clogged fast. You need to also think about the replacement filter with pets. Many replacement filters can be cleaned with a vacuum cleaner.

This saves you on the cost of buying more filters and it improves the air flow through the filters. Another consideration is odours. For a musty type of smell a good activated carbon filter will make your room smell better. For other types of odours carbon is hit or miss. Your best bet for odours in carpeting or difficult to remove areas is to use a good carpet cleaner. An air purifier will help somewhat but you are

better off removing the issue at the source. An air purifier is not a solution for every problem. Difficult pet odours is one such area.

Another suggestion for pet dander is to use a HEPA vacuum cleaner. While this vacuum does a better job in removing hair and dander, it will kick up dander and dust into the air. If you suffer from allergies it’s best to find someone else to do this for you. Also, a dust mask is good to wear to avoid breathing in the particles.

COPD, like asthma is a serious condition. With COPD you have a compromised respiratory system. COPD is the abbreviation for Chronic Obstructive Pulmonary Disease. We get many calls from people with bronchitis and emphysema that have hard time breathing. This is the third leading cause of death in the USA. It affects millions of us and is not to be taken lightly. We recommend following the suggestions for asthma given above.

VOC’s, chemicals and gases are the most difficult to remove from the air. A HEPA filter is pretty worthless for gases. You need media like carbon. While activated carbon works well for many gases it does not work well for all gases.

The best thing you can do is to remove the source of the gas. If this is not possible, natural ventilation is good option. Carbon works well for a wide spectrum of gases including smoke, pet odours, and pollution.

For radon, a carbon filter will help somewhat but we suggest you ventilate as much as possible. For formaldehyde, benzene, sewer gas and natural gas you will want more than just carbon. We use potassium permanganate. This works well in providing a complete solution.

To remove bacteria from the air the best option is a true HEPA filter. The fibres in a filter of this efficiency are so small they will capture bacteria that are passing through. This is especially important if you are in an area that may have Legionella bacteria. As you may know this can result in Legionnaire’s disease. The bacteria that is associated with Legionnaire disease is often spread through airborne water droplets or vapour that contains the bacteria. Examples of the sources include air conditioning systems in commercial buildings, spas, etc.

Viruses are living organisms and the best way to kill them is with a high power UV-C germicidal lamp. A HEPA air cleaner can catch viruses. However since viruses are tiny you will want to go with a high-end HEPA filter otherwise the viruses will pass through the filter fibres.

We suggest using an air purifier where you spend most of your time indoors. In most cases this is a bedroom or office. The air filtration ability of most air purifiers is relegated to a single room. Some people like the option of moving an air purifier with them. In this case you want to make sure it is portable HEPA air cleaner.

You will find most air purifiers either have wheels or a carrying handle. This makes it simple to move. If the air purifier has wheels, chances are it will be more difficult to carry up and down stairs. This will be due to the added size or weight. If this is the case be sure to check the weight of the unit before you buy.

Most people use an air purifier in the bedroom. This is because most of us sleep 7-8 hours a day. And the bedroom is where we spend most of our time at home. If you have allergies and want to wake up feeling better you will want to run an air purifier in your bedroom. It’s best to keep the air from mixing in from other rooms. To achieve this you may want to close your door. You will also want to make sure the air purifier is sized for your room. This means having enough air flow to circulate the air 3-4 times per hour.

And a high efficiency filter to remove the smallest particles.

The challenge with your furnace filter is that it is not designed to remove the small particles, those that cause health issues. And they do not remove gases or odours. There are a few different options for you for cleaning a whole house.

One option is to buy a whole house air purifier that ties into your HVAC system. These are meant to clean areas up to 2,000 square feet. The room coverage is related to the strength of the air handler. So, if your HVAC system can cool 1,000 square foot, that will be how much air cleaning you get.

This type of whole home air cleaner requires an installation. They are nice in that it is out of sight. The downside besides the installation and cost is that it only filters while the HVAC fan is running. So, it’s not always cleaning the air.

Another option is to buy a light commercial air purifier like the Erik650A air purifier. They are more of a portable whole house air cleaner.

A third option is to buy air purifier bundles for the rooms where you spend most of your time. Or if you live in a tiny house such as 500 sqft you can get air cleaning for the whole house with just one unit. We know this is not the case for most of you. With particle counter testing we find a room air purifier works better than the whole house installed option. This is because a dedicated fan in the true HEPA air purifier filter can move enough air to clean the full square footage of your room constantly.

Buying an air purifier is an investment in your health and wellbeing. Given this you want to make sure you get the performance you need. As we have seen with the Ionic Breeze air cleaner, something that is too good to be true probably is. In some regions, the car air purifier is popular. In our humble opinion car air purifiers are not worth the money since they offer little to no air filtration.

The air purifier market has changed a lot since the days of the Ionic Breeze air cleaner. Since then we have seen good growth for higher end air purifiers as higher levels of air filtration are sought. Depending upon why you need an air purifier you will want to ensure it solves your specific issue. If you need to remove particulates you will want a high efficient HEPA filter. A good filter is not cheap. You get what you pay for.

There are standards for how filters are rated. You will want to ensure the filter you are getting have a high MERV rating. And have plenty of filter media so it performs well over time.

An air purifier is meant to clean your air. If it produces ozone it is introducing pollution into your home.
This is the opposite of what you want.


In this article we introduced room air purifiers with a focus on performance and what you need to look for. We reviewed why you need to care about indoor air quality. Indoor air can be 5 to 100 times more polluted than outdoor air and how this affects your health.

There are three key strategies for better indoor air. They are source control, ventilation and air cleaning. We went into what an air purifier is and how they work. We reviewed the air purification technologies like HEPA purifier filters, activated carbon, electrostatic precipitators, electronic air cleaners, ozone generators, and air ionisers. Why HEPA filters are best for particles and why a HEPA air purifier alone is not good for gases or odours such as tobacco smoke. For that you need activated carbon. We described how you activate carbon. In some cases even need to go beyond with treated carbon filters to remove gases like formaldehyde.

We also explained how true HEPA air filters and HEPA-type filters are different. What really matters is the filter efficiency. To properly compare you should look for the filter MERV rating.

An air cleaning device is great solution for many indoor air quality issues. We recognize that a home air filtration system in an investment in your health. But as we show it is not the right solution in all cases. If you have any questions, please do not hesitate to contact us.

What is the best Air Purifier living in close proximity to a freeway?

  • Exhaust and air pollution from cars will impact the indoor air quality if you live close to a highway. The pollutants are a mix of fine particulates also known as PM2.5. This means airborne particles smaller than 2.5 microns in diameter. It is a mix of harmful gases.
  • So, the best way to improve your indoor air is to that the same approach as removing secondhand smoke. You will want a high quality true HEPA filter and at least 3 pounds of activated carbon in the air filtration system.
  • The HEPA will remove the PM2.5 particulates and the carbon will get rid of the harmful gases. If you need gas or odour removal you will need a good amount of activated carbon. Depending upon the gas you may need other types of gas media. A thin carbon filter will not cut it.

How quickly will a HEPA air filter make a difference with a dust mite allergy?

  •  As with most questions related to air cleaners, it depends on the room size, air flow of the air purifier and air filter quality. AHAM (Association of Home Appliance Manufacturers) has a standard called CADR (clean air delivery rate). Basically it is a metric that represents the filtered air flow rate. It is measured in cubic feet per minute (cfm). If the filter is a true HEPA (99.97% efficient) and has a cfm air flow of 200 then the CADR will be at or just below 200. If the filter efficiency is 70%, the CADR will be 140 (200 x 70%).
  • Ideally you want 4-6 air changes per hour in a room. So, to have all the air cleaned about every 15 minutes. The AHAM standard is to take the CADR and multiply by 1.5 to have the optimal room size. So, if the CADR is 200 it can effectively clean a 300 sqft room with the air cleaned every 15 minutes. In the air purifier market we see some products where the CADR is not listed. Some air purifier design are really cool but if it doesn’t move enough air you will not get the performance needed to remove airborne allergens. Some might include an app but we take a different approach in that we do not feel you need another app on your phone. If made properly the air cleaning device can monitor the air and adjust as needed to clean your air. And you can spend time on other things and know we have the clean, fresh air taken care of.

How do dehumidifiers and air purifiers differ?

  • Dehumidifiers remove humidity from a room as the primary function while air purifiers remove airborne particles and/or gases. Dehumidifiers have a compressor and are basically half of an air conditioner. They typically have a small screen filter that can remove very large dust particles but not the smaller particles that air purifiers are designed to capture.
  • They are similar in that they both help with mold spore removal. A dehumidifier will remove the water and humidity that mold thrives on. While an air purifier will remove the mold spore particles from the air that cause allergy and asthma issues. An air purifier can also help with mold odours if it has sufficient amounts of activated carbon. An air purifier does not have a compressor.

Is it stupid to get an air purifier if I leave a window open?

  • This question reminds me of a visit we had with an air cleaner distributor in China. This was at their office in Shanghai and the air pollution with high on this day. It was surprising to see that the owner of the company running an air purifier in his office with the windows open. Given the air pollution levels it seemed absurd for anyone to do this, especially someone who is in the air purifier market. I assume it is cultural or maybe feng shui related.
    To answer the question, any air filtration system will be worthless if you have the window open.
    There is simply too much outdoor air mixing in for the air cleaner to keep up.

Does it matter which way around a HEPA filter is installed?

  • Yes, if the HEPA filter has a seal. The seal is important as it prevents air from by-passing the filter. If the filter is loaded the wrong way the air coming out will not be as clean. We have good seals on all of our air filters. For example, are able to show 100% pure air coming out of our EJ120 model.

Which are air purifier indoor plants?

  • There are some articles out there promoting indoor plants as a home air cleaner. The basis is research from NASA in 1989. The findings are that certain household plants such as aloe vera, Florist’s chrysanthemum, Red-edged dracaena, Bamboo palm, Chinese evergreen, Spider plant and English ivy can naturally remove toxic agents such as benzene and formaldehyde.
  • NASA was looking for a way to improve indoor air in space stations. Carbon dioxide is a perpetual issue. So, they did a study and found good results for certain gas removal with these plants. While these common household plants can improve your air quality they will do nothing to help with airborne allergens and some are toxic to cats and dogs. Nor will a plant air purifier.

Are air filters and dehumidifiers useful for allergies?

  •  In a word – yes, especially the air filter. The larger allergens are generally not a problem since they either settle to the floor or are filtered by your nasal passage. The smaller allergy particles are the problem. The smaller and lighter the particle the longer it will stay suspended in the air. It’s also most likely to be breathed deep into your lungs since it will pass through your nasal system. If very small they can enter your blood stream. This is why the air pollution in India and China is so dangerous.
  • The air filter for your HVAC system is made to protect the HVAC system from large dust so it runs efficiently. It’s not meant to provide allergy relief for you. The best choice to remove the allergens is with a true HEPA filter. When buying a HEPA filter you will need sufficient air flow so it cleans the air in your room every 15 minutes. For most people the best place to use a HEPA filter is in your bedroom, since this is where you spend most of your time. Bedrooms also tend to be smaller than living rooms so a HEPA air purifier will do a better job there. Dehumidifiers can help if you need to reduce humidity levels to control mold. For dust or pollen it will help much. In winter if you are running the heat, then the humidity levels should be low and so there is likely no point in running a dehumidifier. When it is humid, an air conditioner or dehumidifier will help your indoor air quality by reducing humidity levels.

I have an allergy to dust mites, but I can’t remove the wall to wall carpet. Any idea on how to reduce my symptoms without taking medicines?

Here are 5 steps you can take to remove dust mite allergens.

  1. Dust mites need a water source to survive. Use a dehumidifier or air conditioner to keep the relative humidity below 50%.
  2. Buy a true HEPA air purifier with a high air flow to turn your room into a clean room. Here are the best air purifiers for dust removal.
  3. Keep things clean. A vacuum cleaner will stir up dust and dust mites. A HEPA vacuum cleaner can help although in testing this one day there was so much dust coming out it broke our particle counter. So, these may be only minimally effective. Wear a mask or get someone else to vacuum for you is ideal if you can do so.
  4. Cover your pillows and mattress in an allergen cover. Wash all bedding and blankets at least weekly in hot water to kill the dust mites. They also live in your carpeting but frequent cleaning of your sheets is sure to help.
  5. Use a damp cloth when dusting. If you use a dry cloth it sends the dust mite allergens into the air which is the opposite of what you want.

Can I stay in my house when using an ionizer blower fan?

  • By this I assume you mean a negative air ionizer. This device emits an electronic charge into the air. The California Air Resources Board (CARB) maintains a listing of all certified air cleaners that meet the ozone standards. Any of these should be safe to use. CARB also has a list of potentially dangerous products that emit higher levels of ozone.

What is it like to work in a room with an air purifier?

  • We have offices in the US and China. We use our air purifiers in both places although for different reasons. In the US, we are concerned mostly with asthma and allergens. We run EJ120 air cleaners on a middle fan speed. Since we use a German motor at this fan speed it is quiet.
  • After a day or two of working you don’t even notice that it’s running. We use true HEPA filters and activated carbon without any off-gassing glue so it has no odours. The air is clean and fresh.
  • In China, we worry about the air pollution. We also use the EJ120 air cleaner and run them on fan speed 4 to move more air flow. The room has a larger square footage. Not to mention the added air pollutants. And yet it’s still fairly quiet. You really notice the difference since the air so much fresher. It’s like a bubble of clean air and smells so much better.
  • The US National Institutes of Health (NIH) did a study that showed better indoor air quality can result in 6%-9% higher worker productivity. This may not sound like a lot but employee salaries make up 90% of costs in an office so a 6–9% productivity improvement adds up to a lot.

Better components and better engineering talent produce a better air purifier. We know first-hand what it’s like to suffer with allergies and asthma. As users of our products we take a customer viewpoint. The product has to work and be easy to use. Best in class filters that work better and last longer are also important. We are confident we can clean your air since we have helped hundreds of thousands around the world. We see this in customer reviews, hand written letters, emails and customer phone calls.

Everyone deserves to breathe clean air. And feel your best.

Ionic and HEPA air purifiers are designed to improve indoor air quality. They are different in their effectiveness. Below we give some history and break down the differences between the two types of air purifiers. We explain why HEPA air purifiers are ideal for you in almost every instance, especially if you want clean, fresh air. We will also share some secrets of the air purifier industry related to air ionizers.

Which Air Purifier is Most Popular?
In the 1990’s, ionic air purifiers were popular; in particular, the Sharper Image Ionic Breeze.

There is also a similar model, the Ionic Pro air cleaner.
In the early 2000’s the Ionic Breeze air cleaner received unfavourable reviews. This was from a result of improved air cleaner testing and then had a spat with the Consumer Union.

Since then, HEPA air purifiers have become much more popular. Today, HEPA is the most common type of air purifier purchased.

How Ionic Air Purifiers Work
There are actually two types of ionic air purifiers, Electrostatic Precipitators and Air Ionizers. In both cases these are “filter-less” air cleaners. They are also known as an electronic air cleaner.

Electrostatic precipitators have positive and negative charged plates. Particulates collect on the plates as they pass through the air purifier. Rather than having to replace the filter, you must wash or clean the plates. While it is beneficial from a cost standpoint, you give up a lot in performance compared to a HEPA filter.

The filter-less air purifiers simply do not remove the particulates effectively. They do not do a good job removing the smallest, most dangerous particles. These are the particles that float in the air for hours or days and can be breathed deep into your lungs.

An electrostatic precipitators’ performance is best when the plates are clean. Yet, even at that point, it performs much worse when compared to a HEPA filter. To make matters worse, when the plates become dirty, the performance degrades further.

It is common for ozone to be produced as a by-product of the charged plates. Ozone is considered indoor air pollution. We see this often with car air purifiers and it’s not what you would expect from an air purification system. For someone with a sensitive system such as COPD, emphysema or asthma, ozone can be a huge problem. Room air purifiers are now tested to meet ozone requirements. As a result there has been a large shift away from ionic air
purifiers to HEPA filter air purifiers. It’s somewhat difficult to even find an ozone generating purifier now and with good reason. In our opinion, the last thing you want an air purifier to do is introduce a pollutant into your home. Your expectation is your home will have clean air rather than ending up with high levels of ozone.

While we are harsh on ozone generators there is one area where they work well. This is in cigarette smoke removal from a room. Commercial ozone generators like this are used in hotel rooms to remove difficult tobacco smoke smells. Ozone air purification is sold only as a commercial air purifier since the State of California does not allow them to be sold to consumers. Since California is such a powerful state, it’s had the effect of limiting the sales

The other type of ionic air cleaner is an air ionizer. These air purifiers don’t actually have a filter. In some cases not even a motor. This is referred to as a negative ion generator because they emit a negative ion charge that is meant to attach to the airborne particulates. The idea is that once the airborne particles like dust, pollen, or a mold spore take on the electrical charge they will be more likely to stick to surfaces.

A problem with this approach is it the particles don’t discriminate in what they attach to. It could be the carpeting, walls, your clothes and worst case – your lungs. For mold spores, you really don’t want them floating and then sticking to the walls. You want to catch them in the room air purifier. Air ionizers are not recommended for relief from allergies or any other respiratory condition.

HEPA filters were developed by the US military during World War II as a way to create an effective gas mask. The technology has not changed much since then. For air cleaning performance, HEPA air filters are the best technology. They remove the most airborne

contaminants as well as the most dangerous particulates. Besides, HEPA filters become more efficient over time. Meaning they remove more with use.

Airplanes use HEPA filters. That’s because they are great in removing bacteria as well as other tiny particles. They get a bad rap sometimes. On a plane the issue has more to do with whether they are moving enough air or your neighbour who coughs on you. Tesla is now using HEPA filters. They even have a cool name for it. The Bioweapon Defence Mode.

When we say HEPA filters, we mean true HEPA filters. There is a standard called the MERV ratings scale that rates air filters in the US. The scale goes from 1 to 18, with 18 having the highest efficiency. The air purifier filters that we make are all in the MERV 16-18 range. The OV200 and Max v-HEPA are MERV 16. The EJ120 is MERV 17. The ERIK650A is MERV 18 and is used as a high-end home air purifier or as a commercial air purifier.

Other brands call their filters names like HEPA-type filter or a marketing term with “HEPA” added in. In many, filters like this especially the HEPA-type air filters have a lower efficiency that genuine true HEPA filters.

HEPA air filters need replacement at some point. This is for the sake of ensuring you are getting a high level of air cleaning. As the filters collect particles like pet dander, mold spores, pollen, and other airborne allergens, the airflow resistance will increase. This results in less airflow

through the filter and lower air cleaning performance. If the filter is clogged it will have a difficult time in moving the air to clean your room.

Safety is also best. HEPA filters only use mechanical filtration. They do not generate any unwanted air pollutants such as ozone. If you are looking for a recommendation, consider the

Oransi Max v-HEPA air purifier. It is ranked #1 air purifier by an independent study at Clemson University.

In many cases when you buy a HEPA air purifier it will also have a negative ionizer. This is done to give a boost to the air cleaning performance. If you do not want a negative ionizer your choices among brands are limited. The EJ120 and ERIK650A air purifiers we make do not have an ionizer. Our OV200 HEPA air cleaner also does not have a negative ionizer. As mentioned earlier, the concern with an ionizer is that it will generate ozone. The state of California requires all air purifiers to be lab tested.

Negative Ionizers are small devices that create a negative charge. This charge allows the HEPA filter to capture more particles. Ion generators come in different shapes and are small in size similar to a dental floss container.