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Air Purifier - From A to Z: The Complete Beginners Guide

Are you unsure about what makes a good air purifier or do you need help choosing the best air cleaner?

In this guide we will give you an overview on what you need to do to clean your indoor air so you can be breathing in fresh, clean air everyday.


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.

Our focus at Oransi is on quality air purifier performance and ease of use instead of prioritizing aesthetic design and smart tech. We want to make the best air purifiers we can that take in air, filter out any nasty particles, and push out the clean air that you breathe.


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 oursevles we know what it is like to struggle and not feel well.

Here is Oransi CEO Peter Mann's story: My son struggled with asthma. We did all the usual things and even removed the carpeting, but nothing helped.

His doctor prescribed a steroid that he breathed in with a nebulizer and mask. The medicine changed him. One change was his discolored 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 about me.

Let's get started. We hope you find this guide helpful.

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



In this article we will cover:

  • Why you need to care about indoor air quality
  • 3 Strategies to improve indoor air
  • What is an air purifier?
  • How an air purifier works
  • Types of air purification systems and how to choose the best air purifier
  • What an air cleaner can and can't do


Why you need to care about indoor air quality

The World Health Organization measures indoor and outdoor air pollution. They report 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 and heating 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.

energy costs

Even in well ventilated places like an older apartment there are issues. Pollution or secondhand smoke can come in from your neighbor. Or from a highway. As can pollen, mold and dust. Any airborne particle can easily move and that makes it challenging to live in a pure environment.

Common sources 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 are brought in from the outside.

If it seems like allergies are getting worse every year, that's because they are. This chart shows the trends.

pollen trends

Source: Comedy Central

Remember the formaldehyde issues from flooring by Lumber Liquidators and dry wall issues?

formaldehyde gas issues

There are also issues related to gas leaks. And this issue is expected to continue. The New York Times and USA Today reported on this.

Indoor air not only impacts your life at home.

This study 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.

We talk with customers every day who suffer from allergies and just want a good night's sleep. We wrote this article on how to sleep with allergies.


How to improve your indoor air quality

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. This is the best thing you can do. If you can completely remove the source you should not need an air purifier.

The problem is this is not always possible. Or some people just don't want to do this.

Let's consider pet dander. So what this means is, if you want to remove pet dander then get rid of your pet. For most people this is not an option. 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, TX 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 vapors and particulates. You are not going to not use your printer.

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 space. This is a good option if you have volatile organic compounds (VOCs) or gases. These organics compounds can originate from a number of places. By definition a volatile organic compound is an organic compound that can easily become a gas or vapor.

Common indoor air pollutants come from cleaning supplies, furniture, or flooring. These materials off gas chemicals that in many cases are not good for you. Some like formaldehyde have been shown to cause cancer. Sadly, hazardous air pollutants are part of our every day lives. Other examples of volatile organic compounds include vapors from paint and coatings.


In a home your air conditioning or forced-air heating 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 going 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 limit 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 was 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.


What is an air purifier?

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.


what is an air purifier

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. This is the National Institute for Occupational Safety and Health which is part of the CDC.

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 95% of particles and resistant to oil
  • P100: Filters at least 99.97% of particles and resistant to oil


face mask

This standard is important since it gives you an idea for how well the filters perform.

An N95 mask filters out 95% of particles, which sounds like a good number, but it just filters out the large particles.The reason is because fine particles and gases are too small to be removed by a filter that only removes 95%. 95% is relatively low when compared to our air purifiers which filter out fine particles and gases at over 99%.


How to think about air purifiers

A good way to think about air purifiers is to compare them to masks.

If you care most about air purifier performance this is for you.

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 filters that used HEPA based materials.


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.


What's in the air?

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. Odors 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.

What makes it so difficult to compare air purifiers is that the gases and tiny particles are too small to be seen. It is further complicated because so many products are sold based on looks and price.

So, how do you know it's 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 high efficiency air filter captures particles as they pass through the filter. Think of it as weaved fibers like in our clothes. But a much tighter weave.

The performance of a high efficiency air filter filter can vary a lot. This is due to the quality of the fiber material, the amount of filter media and the tightness of the weave.

Most air purifiers say they have a high efficiency air filter and what they mean is they have a pleated filter. It's best to look at the CADR number of a product to understand a purifier's filter and air flow effectiveness. 

Like the NIOSH mask filters, air filters have a rating scale. It is called MERV. Based on the MERV rating 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 cleanroom or high-end biosafety 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.


What is an air filter made of?

There are usually two types of material used in air filters. One is glass fiber (fiberglass). The other is synthetic fibers.

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


Do Air Purifiers Really Work?

An air purifier can provide the fresh air you're looking for as long as it has enough air flow and the right type and amount of filter media. Keep reading below to learn what you need to know to make sure the air cleaner you buy meets your needs.

CADR (Clean Air Delivery Rate)

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 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.

Testing Agencies

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.

aham cadr air purifiers

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.


How to Know Room Coverage

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.

Sq Ft Coverage Based on CADR and Air Changes

How to know cadr room square footage

To learn more see how much square footage an air purifier will clean.

So, how did we get to the CADR?

Let us share a story.

In the 1990's a company called The Sharper Image introduced the Ionic Breeze. This was marketed as a filterless air purifier that cleaned the air and removed odors. 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 odors so well was because it produced ozone. Ozone is great at removing odors 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 circulate the air in a room. It seemed to 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 certified that it does not produce excess ozone. Since the state of California is so large, it has influenced the national market.

The CADR also became more prominent with the case of the Ionic Breeze. This was how the testing agencies evaluated the performance. Or lack there of. A prominent air purifier review essentially torpedoed them.


How an air purifier removes gases

What we have covered above is how a high efficiency air filter removes particles. For many, gas removal is also wanted. This can be for odors, chemicals, VOCs, formaldehyde, pollution, natural gas and others.

The challenge with HEPA based filter media is that the gases are so small they pass right through. What works is to adsorb them through a different type of filter.

The most common is carbon. In it's 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 carbon is not created equal. 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 odors. GAC means the carbon is in pellet form. And 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.

As we said earlier, gas removal can be difficult. Activated carbon works well for many gases but does not work well for all gases.

Here is a chart that shows what carbon is good for. Carbon is good in removing substances with a value of 4. Carbon is not good for items with a value of 1.

gases removed by carbon


One common gas that carbon is not effective for is formaldehyde. Carbon is also not so good in removing natural gases.

In 2015 there was a large gas leak in the Los Angeles area. This resulted in thousands of people having to be relocated. They also relocated a couple schools. Methane and benzene gas leaks are not uncommon.

In response to this the California EPA (Air Resources Board) evaluated filters. They suggested non-carbon filter medias that can be effective. An example is the filters we use in our EJ Air Purifier and Erik air purifiers.


Why you need to replace filters

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 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.


Types of Air Purifiers

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

HEPA Filter Based Media in an Air Purifier

The most popular type of air purifier filter media is HEPA. When a product says it has a HEPA filter it usually means it is a pleated air purifier filter made of HEPA based media. It often does not reflect the performance of the filter. You can determine this with the MERV rating and the CADR number.

The MERV ratings scale and official CADR number from ENERGY STAR is a better way to compare air purifiers. 

Some air purifiers also have a gas filter. This is usually an activated carbon filter for general gas and odor removal. For gases like formaldehyde, you should make sure other media is included. For this you will often see potassium permanganate.

HEPA filter media is so popular because it works the best and is a proven safe air cleaning filter technology. It has the highest efficiencies.

It also is the safest as it does not create pollution like ozone.


    Are Air Purifiers Worth It?

    After working with thousands of customers, air purifiers are worth it provided you choose a solution that can effectively solve your indoor air quality problem. If you want to learn more see how to choose an air purifier. This guide will take you step-by-step to make sure you find the right air cleaner for your situation.


    Ionic Air Purifiers

    Ionic air purifiers like the Ionic Breeze use charged plates to collect dust. This works like a TV screen that has a static charge and has dust on it.

    The principle is that you have a permanent filter or filterless system that cleans your air. In testing the efficiencies are low. So, it's not cleaning the room well.

    The other challenge is ionic air cleaners tend to generate ozone.

    20 years ago more than half of the air purifiers sold were ionic type. Air ionizers were everywhere. With the government standards this has changed.

    We go into depth on the differences between ionic and HEPA filter based media air purifiers in the link above. These systems are also referred to as negative ionizers.

    To go one step further some room air purifiers use Sharp Plasmacluster technology. This was developed by Sharp and works by emitting positive and negative ions into a room. It is promoted as a disinfecting technology. There is a similar technology called Plasmawave technology by Winix.

    Since we have been making air purifiers for many years and know the industry well, it's funny to us when we see products promoted for using air ionisers. Especially when it's the main means of air cleaning. I don't mean to be snobby or arrogant but to us this is code for the filter is not so great, if it even has a filter. Otherwise you wouldn't need the ionizer. Products that have an air ionizer don't have the super high quality air filters.


    Electrostatic Precipitators

    Electrostatic precipitators work similar to ionic cleaners in that they use an electrical charge to remove pollutants from the air.

    Electrostatic precipitators, also known as ESP, have a series of plates. One plate has a negative charge (negative ion) and the other has a positive charge(positive ion). This system is sometimes referred to as an electronic air cleaner since the primary air filtration technology is electronic.

    It works similar to a magnet, where a charge is emitted into the air where it attaches to a particle. This charged particle then drawn to the plate with the opposite charge.


    Ozone Generators

    An ozone generator exists for the sole purpose of creating ozone. They are now used for commercial purposes in controlled environments.

    An example is smoke removal. If smoke is embedded into fabric, a ozone can be effective in neutralizing this. It's just not safe to inhale. You do not want to be around when an ozone air purifier is operating.

    While you may think this sounds great, there is a problem: ozone is bad for your lungs.

    In 2010, the State of California created ozone standards for air cleaners. In effect, this shut down the sales of ozone air cleaners for the consumer market. As a consumer in California, you cannot buy these for a home air purification system.

    Since it is now illegal to sell air purifiers that produce excess levels of ozone to residents of California many of the brands at that time now position themselves as commercial air purifiers.

    This is what the California Air Resources Board has to say. "Some devices that are advertised as "air purifiers", air cleaners, or ozone generators purposely emit large amounts of ozone, the main component of smog! Not only are such ozone generators ineffective at cleaning indoor air, but breathing ozone poses serious health risks."

    Some popular products that are classified as ozone generators include Air Oasis, Alpine Air and Living Air. We have nothing against these brands or products. Just restating what is on the CARB (California EPA site).


    UV Air Purifiers

    An air purifier that has a UV-C light is considered a UV air purifier. UV-C lamps are commonly used as a sterilizer and in places where there is standing water to prevent mold growth.

    There are different types of ultraviolet light. They are classified based on the ultraviolet light wavelength. UV-A light, also known as a black light lamp is classified is long wave light. For example, the fluorescent lamp they use in tanning salons and with reptiles.

    UV-C germicidal lights in contrast are shortwave uv lamps. The purpose of an ultraviolet lamp is for disinfection purposes.

    The most effective uv air cleaners are the large lamps you find in air ducts. To work well you need a strong uv-c light bulb and a sufficient amount of time to sterilize the area. The example of standing water is ideal as a strong UV lamp shining on stagnant water will help prevent mold from growing. UV lights for HVAC systems can be anywhere from 30 to 300 watts. For a UV germicidal room air purifier the UV light bulb is more in the 5-9 watt range.

    There is no such thing as a UV air filter. Rather, UV-c lights are sometimes used in combination with a high efficiency air filter to add a level of disinfection. This UV-c light technology requires a high exposure time that makes it only ideal for issues like mold removal.  


    Air Scrubber

    An air scrubber is another type of commercial air purifier. We go into detail about the different types of air scrubbers here and how they compare.

    Air scrubbers are often used in industrial or office settings for the removal of dust, smoke or other particulates. The room sizes tend to be much larger than you will see in a home. Although for rooms that are more than 1,000 square feet, an industrial or commercial grade air purifier is what is needed.


    What an Air Purifier Can and Can't Do

    Air purifiers are wonderful machines, but they can't do everything. In this section we will cover what they do well and not so well.

    We've broken this section out by concern and room type so you can zero in on what you care about.


    Find the Best Air Purifier for Allergies

    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 filter and motor quality. This is because allergens are airborne particulates. A high efficiency air 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. Really, anything large enough to see.

    When a pre-filter is used it protects the high efficiency air filter and keeps it from being clogged so easily. This extends the life of the filter. And it enables the 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.

    Unless you need odor 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 sq ft 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 air purifiers produce a white noise. The noise level is related to the quality of the motor and the resistance of the filter.

    Here are other steps you can take to get allergy relief.

    • If you have pollen allergies, take off your shoes when you get home. Change your clothes. Wash your face. Consider taking a shower. The key is to remove the pollen from your body and limit the amount you bring inside.
    • Allergy medicine can provide some relief but they take some time for your body to build up the immunity. If you are already feeling the effects of allergens, allergy medicine will take time.
    • Source control is a key strategy to better air quality. You can apply this to pollen allergies by limiting your time outside.


    Find the Best Air Filter to Reduce Dust

    Dust is a common problem. It's interesting because dust takes a variety of forms.

    If you live in dry places like Arizona, there is a dust season that creates problems.

    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. We have written in depth on dust mites here. This article outlines why dust mites are a problem and what you can do.

    Dust is also a problem from birds. Also known as feather dust. Birds can create vast amounts of this and it creates a health problem for you and the birds. We wrote bird dander air purifier with everything you need to know.

    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 get a good air purifier for dust.

    So, get a good 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 not a place you want to be.

    Since dust is a particulate you should focus on a high efficiency air 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 filter the more of these small dust particles can be removed from your air. You will want a high efficiency filter.


    Find the Best Air Purifier for Asthma

    The reason we started this business was to help those who suffer with respiratory issues. Especially asthma. And make the best air purifiers for asthma.

    There are many asthma triggers and the key is to get rid of them. We have written about the relationship between allergies and asthma.

    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 mites.
    • Clean with a vacuum cleaner. Wear a mask to keep from inhaling the particles that are kicked up.
    • Reduce outdoor activity on high pollen days and when ozone levels are higher.
    • Use an air purifier with a high CADR number,  high efficiency air filter, and strong motor quality


    For someone with asthma you will want to go with a home air purifier that has a high efficiency filter. Especially babies and kids

    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 higher the better.

    The goal is to turn your room into a clean room.


    Find the Best Air Purifier for Mold

    Mold and mildew is a problem for many people. We have written a complete guide about mold here.

    In the article we go into depth on how to remove mold. And the difference between mold and mildew. Along with a variety of other mold topics.

    We also highlight the best air purifiers for mold.

    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 odors.

    You need an air purifier for this.

    Like with allergies you will want a high efficiency air filter to remove the small mold spores. Cheaper filters will only collect the large dust in your room. Purifiers with high efficiency air filter and a strong quality motor can remove mold particles big and small. 

    If you suffer from nasal congestion see 19 ways to relieve sinus congestion from allergies.

    If you need odor removal then should also have an activated carbon filter. This carbon is great for a wide range of gases including mold related odors.


    Find the Best Air Purifier for Smoke Removal

    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 odor. 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 air filter. The larger the better. The more efficient the better.

    You also need a strong carbon filter. Activated carbon does a good job in adsorbing smoke gases and odors. The problem with only having HEPA filter based media is the smoke odor will not be removed.

    In looking at our air purifiers, the best air purifiers for smoke removal are the Mod and TrueCarbon series. This is because they have the right amount of activated carbon filtration. 


    Find the Best Air Purifier for Pet Dander

    We often hear about pet dander from dogs and cats, but birds also present issues. If you have a lot of fine dust from birds then a high efficiency air filtration system is a must.

    For the removal of pet dander and pet hair you will want a high efficiency air filter. If you have a lot of pet hair you will want a larger high efficiency air 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 odors. For a musty type of smell a good activated carbon filter will make your room smell better. For other types of odors carbon is hit or miss.

    Your best bet for odors 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 odors is one such area.

    Another suggestion for pet dander is to use a good 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.


    Find the Best Air Purifier for COPD

    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 who have a 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. We have also written about air purifiers for COPD here.


    Find the Best Air Purifier for VOCs and Gases

    VOCs, chemicals and gases are the most difficult to remove from the air. Here are the best air purifiers for VOCs.

    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 odors, 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.

    For odors and gases we suggest these air purifiers for odors.


    Find the Best Air Purifier for Bacteria and Viruses

    To remove bacteria from the air the best option is a high efficiency air filter made out of HEPA based media. The fibers in a filter of this efficiency are so small they will capture bacteria that is 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 vapor that contains the bacteria. Examples of the sources include air conditioning systems in commercial buildings, spas, etc.

    A high efficiency air filter can catch and filter virus particles out of the air. However since viruses are tiny you will want to go with a high-end filter otherwise the viruses will pass through the filter fibers.


    Portable Air Purifiers

    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 air cleaner with a high efficiency air filter.

    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.


    Whole House Air Cleaners

    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 odors.

    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 Erik 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 sq ft 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 air purifier filter can move enough air to clean the full square footage of your room. And do it constantly.


    What to watch out for

    Buying an air purifier is an investment in your health and well being. 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. There are other examples of this. The results are similar in the Therapure air purifier reviews. If it does not have a fan or motor - run.

    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. Models like the Whirlpool Whispure and Honeywell air purifiers were popular in the early 2000's. 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 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 effects 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 filter based media, activated carbon, electrostatic precipitators, electronic air cleaners, ozone generators, Plasmacluster and Plasmawave Technology, and air ionizers. And why high efficiency air filters are best for particles. And why a carbon activated filters are good for gases or odors such as tobacco smoke. 

    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 that what really matters is the filter efficiency. To properly compare you should look for the filter MERV rating and the CADR number. Please visit our product pages if you want to see air purifier reviews from our customers. The product reviews are from both home air purifier users and commercial use.

    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. If we do not have the best clean air products for your situation we will suggest a competitor.


    Air Purifier Questions

    After finishing this room air cleaners guide, we decided to add in a bonus with answers to some questions.

    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 second-hand smoke. You will want a high quality high efficiency air filter and at least 3 pounds of activated carbon in the air filtration system.

    The high efficiency air filter will remove the PM2.5 particulates and the carbon will get rid of the harmful gases.

    If you need gas or odor 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. Some high end models with a ton of carbon are the IQAir Dental Pro and Oransi Multi-Carbon air purifiers.


    How quickly will a high efficiency 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 high efficiency air filter 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 and 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 sq ft room with the air cleaned every 15 minutes.

    In the air purifier market we see some products where the CADR is not listed. We would think if the air flow was strong such as with the Dyson air purifiers they would promote this but they don't. The design is really cool but if it doesn't move enough air you will not get the performance needed to remove airborne allergens.

    A trend that we see is some models like the Dyson and Airmega air purifier is to include an app. 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 odors 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?

    To answer this question simply, 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 filter is installed?

    Yes, a typical air purifier 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.


    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 filter made of HEPA based media. 

    When buying a high efficiency air 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 purifier is in your bedroom. Since this is where you spend most of your time. Bedrooms also tend to be smaller than living rooms so an 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.

    In the summer 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 an air purifier that uses safe, proven filter technology and has a high air flow to turn your room into a cleanroom. 

    3. Keep things clean. A vacuum cleaner will stir up dust and dust mites. A good 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 we assume this question is referring to 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.

    For example, the Sharp Plasmacluster air purifier and Blueair HEPASilent air purifiers are on the list as "other" as the technology. And Whirlpool Whispure is listed as "mechanical". Other means there is some sort of electrical device used in the air cleaner. Mechanical means only high efficiency air filters are used. Our V200, EJ and Erik models are all mechanical.

    CARB also has a list of potentially dangerous products that emit higher levels of ozone. Some air cleaners on this list include Air Oasis 3000 Xtreme G3, Alpine Air Living Air Classic and Surround Air Multi-Tech II XJ-3000D.


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

    In our US offices, we are concerned mostly with asthma and allergens. We run EJ 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 high efficiency air filter without any off-gasing glues so it has no odors. The air is clean and fresh.

    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.

    To learn more about our air purifiers, here are the 5 reasons to buy Oransi.

    1. Better filters
    2. Better motor
    3. US based phone support
    4. Better value
    5. Trusted

    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 to feel your best.

    Have more questions?

    Please contact us and our knowledgeable and helpful customer service team would be happy to help.

    *Oransi still offers replacement filters for retired air purifiers.