Ratings of the 15 Best Air Purifiers
Updated for 2017
HEPA air filters consistently outperform every other technology. A true HEPA filter is the preferred filtration technology of government agencies. Also by air quality experts. We discuss more about this below.
How to Use this Guide
We suggest you start with the rankings of the best air purifiers. This will give you an overview for how they are rated. Ratings include ease of use, air flow, filter efficiency, and customer reviews.
In addition, each air purifier is given an overall rating. It is a score based on a 10 point system. As in the air cleaner picture below.
As we test the air purifiers we learn more about the different technologies. We write about them extensively. Here is a summary.
You can find more information on HEPA, electrostatic, UV-C light and ionic air purifiers. If you are looking to clean a room larger than 1,000 sq ft you may want to read our article on commercial air purifiers. These are portable HEPA filtration systems you can use as a whole house air purifier or for commercial use.
We also write about areas where an air purifier can help. This includes allergies and smoke. We are working to add more content to this site. In the meantime, if you have a concern for pet dander, pet hair, airborne mold spores, or dust mite allergies go to our allergies page. These are all airborne particles and the true HEPA air filters that we recommend for allergies will help.
Need to learn about whole house air purifier reviews? See what’s needed to clean a whole house. Or see the best commercial air purifiers. A whole home air cleaner needs some serious power. A commercial grade air cleaner can get the job done.
Now, we have talked a lot about HEPA air purifiers. Yet, HEPA is not a good solution for every indoor air issue. In fact, it’s not so good for odor removal.
If you need tobacco smoke, gas or odor removal you need more than HEPA. Learn about carbon filters here.
If you need additional background you can see what is an air purifier.
First, we will start with a bit of history. Then continue with what we have learned from testing. Most of all the focus is on information to help you improve your indoor air quality.
Air Purifier History
There is an interesting history of air purifiers. It has to do with the Sharper Image Ionic Breeze.
We have mixed feelings toward the history of the Ionic Breeze air purifier. This ionic air cleaner left somewhat of a black mark as a gadget. Ultimately the Ionic Breeze air ioniser left the market since air ionizer reviews have been so poor.
The benefit in all of this is that it helped to generate awareness for improved indoor air quality. So, this is good because indoor air is often polluted than outdoor air.
As much as 100 times more polluted. The main reason is from a pollution source that exists inside. This could be dust in your HVAC system, a pet, cigarette smoke, carpeting, new furniture and many others. Some of the most dangerous include the off-gasing of volatile organic compounds in wood flooring, paint and cleaning supplies. These vapors should be taken seriously as they are indoor air pollutants.
As a result, this has positioned air purifiers that work as solutions for people with allergies and asthma. They are also good for people looking to improve their home environment from smoke smells and odor removal. The models we test are portable air purifiers and if needed they can be easily moved room to room.
How to Find the Best Air Purifier
Here are the key findings from our work.
Our first learning is that different air quality concerns require different solutions. No air purifier is best for every situation. It boils down to a few key factors.
1. It matters what you need removed
A HEPA filter is best for airborne particles. Particles are things like dust, pollen, mold spores, and pet dander.
A HEPA filter works to capture the particles in it’s fibers. A benefit of a true HEPA filter is that this efficiency improves over time. Only a HEPA air filter has this effect.
In contrast, other technologies like ionic air cleaners or electronic air purifiers do not perform as well in testing. And they get worse over time. In testing we found that negative ions alone seem to do nothing to improve the air quality in a room. Yes, they can be silent air purifiers. Yet, in our tests we focus on particle removal. And in this testing we find them to remove very little of the dust pollen particles.
We test with a laser particle counter. This makes it clear as to how well each filter works. You can see the results in the efficiency rating for each air purifier.
We also learned that not all HEPA filters are created equal. Some are HEPA-type filters. This is different than a true HEPA filter that removes technically 99.97% of particles. A HEPA-type air filter removes a lower percentage and there does not seem to be a set standard that they are held to. There is a CADR ratings scale, however several of the HEPA air cleaners that we tested do not show this filter rating with the products.
The air purifiers that test best in measuring filter efficiency are the true HEPA air purifiers. For better air cleaning this is a must.
We also see that most air purifiers have a pre-filter. Some have a carbon pre-filter.
This is a nice touch as the pre-filter will give you better performance since it keeps the HEPA filter from getting clogged with dust, pollen, mold spores, pet hair, pet dander, dust mites and any other dust bunny that might get sucked into the air cleaner.
Best Air Purifier for Dust Removal
To go a little deeper into we will look at a common airborne allergen – dust. Dust can take many forms such as dust mites, particles from your forced-air heating system, from woodworking, pollen dust, dusting from pet dander, etc. You get the point – there are many sources. This mini-guide will show what you need to remove dust from the air.
While this is specific to dust removal you can apply many of these concepts to choosing an air purifier for pets since the particle sizes are similar. The main difference for pets is that you may also want to remove odors. In this case, be sure you read about activated carbon filters below.
Dust particles in the air are of a wide range of sizes. If you can see particles in the air like when the sun is shining through a window, you are seeing the larger one’s. For every big piece of dust you see there are at least 10 times or more smaller particles you cannot see.
As we know from the laws of gravity, the larger and heavier particles will fall to the floor more quickly. As fast as a few seconds. The smallest particles can float for hours or days. This is what you are more likely to breathe in. And what you need to care about most.
The testing we do is with a laser particle counter. So we are able to see exactly how many of the small and large particulates each air purifier can remove. For dust allergy relief you need to remove both. The same goes for any other type of allergen trigger. This is the basis for our air purifier filter efficiency ranking.
Since the big dust particles from sources such as mold spore, animal dander, or a kitty litter box can quickly clog a true HEPA filter, we see air purifiers smartly use a pre-filter. Otherwise your HEPA air filter will clog and not be able to do it’s job. And this saves you from having to buy a replacement filter so often.
Many pre-filters are made from a foam type material. This is a low MERV filter – in the MERV 1 to 4 range. Examples include the Honeywell 50250, Winix Plasmawave 5300, Blueair Hepasilent, Rabbit Air, Finn Whirlpool Whispure, Holmes air purifier, etc. Others like the Oransi EJ and IQAir Healthpro use a more substantial pre-filter.
Do Air Filters Reduce Dust?
In our testing, pleated filters in general do a good job in removing dust particles. If you want to remove the small dust particles that float in the air, you will need a higher efficiency filter. Ideally you want a MERV 17 or better filter if you have a respiratory issue like asthma, COPD or severe allergies. For the large dust that you can see floating you will want to make sure there is a pre-filter otherwise the HEPA filter will clog quickly.
One final thought on carbon-pre-filters is that you will want to see how much activated carbon there is. For many, the foam pre-filter simply has a coating of carbon. In some others like Dyson air purifiers, there are granules of carbon however it is a small amount. Continue reading to learn more about odors, especially cigarette smoke odor removal.
But, before we get to that just want to re-iterate that to remove the smallest dust particles the best way is with a true HEPA filter. The efficiency is high so it is able to remove all dust allergens better than other filter types.
From research we know the HEPA filter is not good with gases. Gases are too small to trap in the fibers.
Gases include odors. They are also fumes from furniture, carpeting and chemicals. So, if you need tobacco smoke removal you need more than HEPA.
So far, we do not test for gas removal. We look online and to date no one has done this testing. It’s difficult to simulate and requires equipment that is out of reach for us. There are many different gases. To measure the performance is beyond our ability.
To overcome this we look at the product specs. We see what is in the carbon filter to remove gases. This gives a good indication for how well it performs.
Here is what we learned about gases. Activated carbon is good for many gases. But, not all.
For smoke removal, activated carbon works well. It also does well with many odors. If you want to learn more about activated carbon air filters including how they activate carbon this page will be worth reading.
Yet, activated carbon is not good for natural gas or formaldehyde removal. For this you more than a carbon filter. If the filter lists gas media beyond carbon it is likely to work well these other gases and odors. Examples of this media include alumina and potassium permanganate.
One final point about smoke removal. Smoke is made up of particles and gases. Therefore, the best air purifiers have a combination of true HEPA and carbon air filters. HEPA filters trap the particles. Carbon catches the smoke gases. You need both for effective air filtration.
2. Air flow is important
In addition to testing filter efficiency we look at the results in a room.
We see some excellent filters. But, when we test we want to know how it does in a room. This is how we use the product.
To factor this in we look at the air flow of the air purifier. A larger air flow means it will clean a bigger room. The best air purifiers have good air flow. More is better.
A criticism of the Ionic Breeze was the lack of air flow.
With our testing we see the low air flow purifiers do not clean as well. It’s like having a small air conditioner trying to cool a large room. It doesn’t work so well. To provide clean air you need to have strong circulation through the air filters.
We test in a bedroom. Within 15 minutes we see improvement in the air quality when a good air purifier is running. Within 15 minutes of turning it off the air quality becomes worse. We see this with the particle counter.
As a result, air purifiers with lower air flow show a lower improvement in the room. From the results they are not moving enough air.
To make this practical, here is an example. We test all air purifiers on the highest fan speed. This is how they are measured for the CADR or Clean Air Delivery Rate.
This number will show how much total air cleaning to expect. CADR is measured in cfm or cubic feet per minute. A higher CADR number indicates it will clean a larger room size.
If you have a 300 square foot sized bedroom with a 10 ft high ceiling your room is 3,000 cubic ft. For two air cleanings per hour you will need to move 6,000 cubic feet per hour of air through the filters. Since CADR is measured per minute, you would then divide 6,000 by 60 to get to 100 CADR.
For allergy and asthma sufferers the air changes number should be more like 4. So, in our example you will then need to move 12,000 cubic ft per hour. This corresponds with a 200 CADR.
Again, this is on the highest fan speed setting with 10 ft high ceilings. If your ceiling is 8 feet high then the math will be different.
If you decrease the fan speed then you will realize a lower CADR. And subsequently have a lower air cleaning ability.
Hopefully this makes sense. As I wrote this it became a little more complicated than intended. An easier way is to multiply the CADR by between 1.6 and 3. If you want the air filtered every 30 minutes use 3 and if you want every 12-15 minutes use 1.6.
Bottom line is when comparing air purifiers you can look at the CADR. Just know a bigger number means you get more air flow through the filters and this becomes more important especially if you have a larger square footage room to clean.
3. Ease of Use
Ease of use does not factor into how well an air purifier works. For us it is a preference. We include it in the ratings since we value usability. We like things that are simple to use and portable.
Hence, if you do not care about this then we suggest you pay more attention to the efficiency and air flow results.
Future Air Purifier Reviews Testing
The testing we do is something we do for fun. As we get to it we will update the site.
From feedback we know that you are looking for some additional air purifier reviews. Some of these air cleaners are too hard to test since they focus on things like smoke odor removal. Products like smoke eaters. We simply don’t have a good way to test these air filtration systems. An example of this is the AirFree Air Sterilizer.
Others like the Alive Air Machine, Edenpure Air Purifier, Fresco Air Cleaner and Alpine Air Cleaner are more like negative ion or ozone generators. Again, we are not set up to test these. Besides, we do not see ozone generators for home use due to health issues related to creating indoor air pollution. They seem to be used exclusively in commercial air cleaning applications. We are only interested in air cleaning products that we would consider for home use.
To touch on ozone is a little more, it’s interesting that this is like ground-level ozone. This occurs when sunlight shines on volatile organic compounds and oxides of nitrogen. The EPA refers to ground level ozone as “bad” ozone since it can trigger a variety of health issues in people and pets.
Some air purifiers have an ultraviolet light. We have a separate article about UV-C light air purifiers. The UV lamps used in large room air purifiers tend to be low wattage. They serve as air sanitizers and can help with things like bacteria and mold growth.
A couple models use plasmawave technology. Sometimes knows an plasmacluster air cleaners. This is similar to an air ionizer with positive and negative ions. We may test these air cleaners in the future as we have time. Another technology is PCO (photocatalytic oxidation) like in Surround Air XJ-3800. This is more of an odor or gas removal technology and not something we expect to be able to test.
A new category that we see online is the car air purifier. After reviewing the specs we most likely will not review these. Some are just mini air ionisers. Others have a HEPA-type filter. We don’t see the point since air cleaners we tested with similar air filters that are larger don’t work well so making the filter and fan smaller will not lead to good results.
This is a bit out there, but there are also plant air purifiers. The idea is that they produce oxygen and remove air pollutants. NASA did a study with plants in the 1980’s since there is a need for oxygen in space. The results show that some plants can clean the air of certain gases although a plant air purifier will not help with airborne particles like mold spores, pet dander, pollen, dust, etc. Again, since we have no way to test for gases, we do not anticipate testing the performance of a plant based air purifier.
We are better set up to check room air purifiers. Some of the requests we have received include testing of the Sharp Plasmacluster ionizer, Winix Plasmawave air purifier, Venta AirWasher, Dyson air purifiers, Febreze air purifier and the Honeywell air purifier. Hopefully in the next year we can get to these in the coming year.
On this page we share the ratings of the best air purifiers. This list is from the products that test best to provide fresh air in a room. We also include customer testimonials into our air purifier reviews. We also use some key findings from CARB.
As a result the key factors we test are ease of use, filter efficiency, and air flow.
Therefore we find that for most situations a HEPA filter air purifier is best. In combination with a good pre-filter you can remove all airborne allergens like dust mites, mold spores, pollen dust, pet hair, and pet dander. The pre-filter may not seem like that big of a deal but it helps to extend the life of the HEPA filter. So you don’t have to worry so much about the replacement filter.
If you have a foam carbon pre-filter the odor removing ability is limited. Furthermore, if your main filter is a HEPA-type filter it will have a lower filter efficiency compared to the true HEPA.
If you need odor or air pollution removal your HEPA filtration system will need activated carbon. Smells from cigarette smoke, for example require larger amounts of activated carbon. This is because tobacco smoke is so strong. Plus, it is a combination of airborne particles and smoke odors so you need a combination of true HEPA filters and active carbon. No one technology can remove all.
Some other air cleaning technologies like an air ioniser or ultraviolet light can complement the HEPA air filter.
One advantage of HEPA and carbon filters is that they do not produce ozone. Ozone is a regulated air pollutant so you will not find ozone generators for home use.
To ensure the air cleaner can clean the square footage in your room you will want to check the Clean Air Delivery Rate. This shows how much air flow passes through the filters. It’s how we display the air flow. If you need to clean spaces larger than 600 sq ft you may want to look at commercial air purifiers for home.