Summary
The air inside your home may be five times dirtier than the air outside. Homes that use less energy are also built to be more protected, which means that more pollution are trapped inside. A lot of everyday things, like food fumes, cleaning products, scents, and pets, can make the air inside your home less than ideal. If the air outside isn’t bad for you, opening your windows and doors is the best way to make the air inside better. But if you can’t let in fresh air, air filters can help lower the level of pollutants, get rid of smells, and catch some bugs and germs. A lot of different types and brands are on the market. We tried a few to make this list of the best filters so you can choose the one that works best for you.
What an air purifier can and can’t do
Volatile organic compounds (VOC), particulate matter (PM2.5 and PM10), and carbon dioxide are the three main toxins that make the air you breathe bad. It’s funny, but air fresheners can give off VOCs along with cleaners, paint, solvents, fragrances, cooking food, and plastics that take off gas. It is most likely that VOCs are linked to smells. High levels can make it hard to breathe, give you headaches, and may even cause cancer over time. Activated charcoal parts in air filters can help get rid of VOCs in the air.
Particulate matter is generally talked about in terms of PM2.5 and PM10, where the numbers show the particle size in microns. This is smoke, dust, dirt, germs, and fumes from making food. PM levels that are too high can irritate the lungs, cause allergy symptoms, cause respiratory illnesses, and even lung cancer. Particulate matter can be taken out of the air by air cleaners with a HEPA filter.
All living things give off carbon dioxide when they breathe out. High amounts can make you feel dizzy and tired. The molecules of CO2 are too small for air purifiers to work, though. Plants can help a little, but the best thing to do is open a window and let some fresh air in.
If you live in California, all air cleaners you buy must be approved by the California Air Resources Board (CARB). There are no government rules for air filters. This list of our top picks all has that approval.
What is the best overall air purifier?
For people who live in dusty places or are sensitive to pet hair and other allergens, allergies can make every day hard. To fight this over time, getting an air filter for your house is a great idea. These are used to move clean air around your house by filtering out viruses, dust, and other air toxins. The BlueAir Blue Pure 311i Max is by far our favorite. This choice is quiet, doesn’t cost too much, and works well in medium-sized rooms. There are other good choices, though, so don’t just look at this one.
The most common and highly ranked type of air cleaner is one that uses HEPA filters. These are high-efficiency particulate air filters that can get rid of at least 99.97% of airborne particles smaller than 0.3 microns, according to the US Department of Energy. Some models say they can clean the air in your whole house, but most can only do one or two rooms at a time. If you have seasonal allergies or live in a wildfire-prone area and want to be ready for the ashes to spread across the US, you might want to get an air filter for your house to protect yourself from airborne toxins.
If you put your air filter in the right spot, it can help people with allergies or other breathing problems. Even if you don’t have any trouble breathing, having an air filter in your home can give you peace of mind that you’re getting the cleanest air possible where you live. Our experts at tkgap have been testing air filters for years. They carefully tried each of the models below over the course of several weeks, looking for any obvious problems with how they worked, how easy they were to use, how quiet they were, and what features they had. Read on to find out more about our top picks, which come straight from the tkgap Labs product testing center.
The best air cleaner for most people
The BlueAir 311i Max
We test every air purifier by putting it right into our own test room and putting controlled amounts of smoke into it. Then we time how long it takes for the filter to clear the air. Our tests showed that BlueAir’s Blue Pure 311i Max was the best medium-sized air cleaner. It got the particle count down to pre-smoke bomb levels in 6.6 minutes on low and 2 minutes on high fan settings. That’s a really great achievement. In addition, the 311i Max was the second most energy-efficient unit in its class. It was also very quiet, with a maximum fan speed of only 46.1 dB.
This is a cool new air cleaner called the Blue Pure 311i Max. It has voice settings, a five-color air quality indicator, and a pollution-detecting particle monitor. You can check the air quality in your home in real time with the BlueAir app. You can also control the air cleaner from afar and see how often the filter needs to be replaced.
However, as of this writing, you can get the Blue Pure 311i Max for less than $230 from both Amazon and Best Buy. BlueAir says it can clean up to 900 square feet and has a 250 cfm CADR grade for dust, pollen, and smoke. It’s a simple, well-designed air cleaner that does a great job of getting rid of particles and using very little energy. If you want to make the air in your home office or gym better, this is the right person for the job.
Blueair Blue Pure 311i Max Review
The best air cleaner for big rooms
The Kenmore Smart 2300e
In big, open areas, it’s especially hard to keep the air clean. The Kenmore Smart 2000e was the most reliable machine in this group. At low, it cleaned the air in our test room in about 6.25 minutes, which was the fastest of the bunch. It came in second at high and only took 2.5 minutes to cross the finish line.
The Kenmore Smart 2300e was also one of the most energy-efficient big air filters we tried. It would cost less each month to run than similar-sized models such as the Coway Airmega 400s or the EnviroKlenz Air System Plus. It wasn’t too loud either; at low and middle settings, the fan noise was below 40 decibels, and at its loudest, it reached 50.6 decibels. That sounds a lot like the noise that rain makes.
It’s easy to clean up to 2,300 square feet with the Kenmore Smart 2300e, which costs less than $300. A digital screen with a color-coded real-time air quality score, three stages of filtration (including an activated carbon filter), and app-control that lets you check the air quality in your home, control the unit from your phone, and order new filters when they need to be replaced are some of the other great features. This is the right air filter for you if you have a very big living room or want to make the air quality in your whole flat better.
The best air cleaner for beds and other small rooms
The BlueAir Pure 511
There are too many great things to say about this air filter. It’s another win for BlueAir, this time in the small price range. In our test to see how well it removed particles, the Pure 511 got the air in our smoke-filled test room back to a safe level in less than 20 minutes on its lowest fan setting. In the same test, every other small air filter we looked at took at least 35 minutes to clean the air. The Pure 511 also won on the high setting, cleaning the room in an impressive 7.5 minutes, which was the fastest in its class.
The BlueAir Pure 511 was also the second quietest small unit we tried. At its loudest setting, the fan made only 44.3 decibels of noise. That is really library-quiet. It also cleans the air very well and uses the second-least amount of power of any air filter we tried, making it the best in its class. In fact, the BlueAir Pure 511 would only add less than $3 to your monthly energy bill if you left it on its top setting 24 hours a day, seven days a week for 30 days in California, where energy costs are much higher than the national average.
The Blue Pure 511 has a CADR of 112 cfm for smoke, pollen, and dust. It can purge up to 432 square feet, and at the time this article was written, it was only $100. It has a HEPA Silent air filter and can be operated with just one button. It’s small, easy to carry, and works well. Our research shows that this is the best air filter for nonstop use in your bedroom. At $100, it’s also a great choice for those on a tight budget.
Things to think about when picking out an air cleaner
Area covered and size
How much space you want to clean is the most important thing to think about when getting an air filter for your home. If you try to save money by buying an air filter that is smaller than what you need, you will be let down. All of the air purifiers on this list work very well, so any of them will clean the air in your home if they’re the right size, put in the right place, and the filters and prefilters are kept in good shape. Next to the size of the room, the device’s size may be important depending on where you want to put it and how the room is laid out.
Plan your budget
When figuring out how much you can spend on an air cleaner, you might also want to think about how much it will cost to replace the filter every six months.
Some kinds of air cleaners
There are a lot of HEPA air filters on the market, and this list only includes the best and most common ones. However, some of them use more than one type of filtration technology. If you want to learn more about those parts of your air filter or if you want to think about getting a different kind, here is a list of all the different ways that air can be cleaned:
According to the term “high efficiency particulate air,” or HEPA air cleaners, use a fiberglass filter to keep particles of a certain size out of the air.
Air purifiers with activated carbon: Most of the air purifiers on this list have activated carbon technology, which is the same thing as activated charcoal. Activated carbon is porous, so it helps filter out gases or volatile organic compounds that are in the air. HEPA filters handle solid particles in the air. People usually notice gasses in their home air as smells from things like cooking, pets, or smokes.
Air filters that use negative ions: These purifiers work by using high voltage to give particles or molecules in the air an electric charge. This makes them stick together and then look for positively charged molecules to join with. For some models that use this technology, there is also a positively charged collecting plate that the electrified particles will stick to and fall out of the air. If you don’t have a gathering plate, these particles will not be moving through the air. Instead, they may stick to surfaces and need to be swept or cleaned out of your home. It takes longer for most models with this technology to clean the air in a room because they don’t use fans. However, it is very quiet inside. Molekule and Dyson both make well-known models that use this kind of technology in different ways.
Air purifiers that use “ultraviolet germicidal irradiation” (UVGI) work in a way that is similar to HEPA air filters in that they use fans to move the air and clean it quickly. UVGI air filters use protected ultraviolet light inside the machine to get rid of dust and allergens. However, this kind of technology isn’t found in air filters for home use. It’s only found in bigger systems used in public places like office buildings.
Place and conditions of life
For some people, having an air filter at home might be more important than nice to have. It can be hard to breathe in the winter because of allergies or because of wildfires and smoky skies where you live. An air cleaner can really help make the air in your home better for breathing. Since the COVID-19 outbreak began and there have been more wildfires, we are all more aware of the quality of the air. (People with serious allergies have probably always been aware of air quality.) Even though an air cleaner won’t always protect you from COVID-19—you’re more likely to get it from close touch with someone in your home than from particles in the air long enough to be filtered out—they can help people with asthma or allergies the most.
What kind of living conditions do you have? If there are a lot of pollutants in the air in your home, air filters can make a big difference in the quality of life (and air) of the people who live there. If you want more information before buying an air filter, you might want to talk to your doctor or an asthmatic.
To find the best air filter for you and your family, you need to do a lot of study and talk to professionals. First, think about how much money you can spend on air cleaning. Do you need an ionic air cleaner or a full system for filtering your whole house? Do you want a cleaner that has a carbon filter that works? We’re here to help you figure out what to do and answer your questions.
How we test air purifiers
To help us choose the best air purifiers, we took 14 of the most popular types to the tkgap Labs center in Louisville, Kentucky, and put them through the same exact set of tests. Our goal, with the help of our trusty lab assistant Eric Snyder, was to find the air filters that did the best job of removing particles, using the least amount of energy, and being as quiet as possible. We also wanted to compare their features and values. Come along as we show you the science behind how we think.
The test to remove particles
This may not be news to you: the air we breathe is not just air. You could see a universe of tiny pieces moving around and being moved by the wind if you went outside in the middle of the night and turned on a lantern. What the heck is that stuff, though?
Actually, it’s a mix of particles that were made by humans and particles that happen spontaneously. The first type is mostly made up of hydrocarbon, nitrogen oxide, and burning leftovers released by cities, factories, and cars. The second type is mostly made up of smoke from forest fires, sulfates, soot, and matter from volcanoes around the world. We are always taking in a mix of all of these things.
Some of these microscopic solids and liquid drops can be made up of hundreds of different chemicals, according to the US Environmental Protection Agency. They are so small that it’s almost certain that you will breathe them in. The most dangerous particles for human health are PM10 and PM2.5, which are less than 10 and 2.5 micrometers in width, respectively. These particles get deep into the lungs and even into the bloodstream when they are breathed in, making the lungs and heart work less well.
These kinds of particles should be taken out of the air by air filters to help us breathe better indoors, but how well do they do that? That’s where our tkgap Labs team comes in handy. To put it simply, our goal was to make a space where we could test each air cleaner unit by exposing it to particle-filled air of about the same percentage. This way, we could see how quickly and effectively they restore breathing conditions.
For this to work, we needed a way to make a consistent and measurable amount of particles, a place to put these particles and the air purifiers, and a precise particle counter that would serve as our guide and let us see the results. The idea we came up with is this:
There are custom-made smoke bombs with a safety fuse for safe lighting from a distance. The bombs are made of 50% potassium nitrate (KNO3), 40% sucrose (sugar), and 10% sodium bicarbonate (baking soda). The potassium nitrate prevents oxidation, the sugar provides fuel, and the baking soda keeps the dry mixture burning slowly and evenly.
Our air filter test room, which Eric and I planned and built. It has a plexiglass front panel that is easy to see through, a gloved hand access on the right that lets us control the air purifiers, a particle counter holder for our control device, two fans that make sure the air and smoke are mixed properly inside the chamber, vent ports that keep a little fresh air coming in at all times, an ignition port for lighting the smoke bombs from outside the rig, and an exhaust port that gets rid of the smoke safely. The space isn’t completely shut, but it’s close enough that no dangerous smoke can get out into the room.
We were able to confirm with the Temtop PMD331 Particle Counter that 5 grams of our smoke bomb dry blend makes between 590 million and 610 million particles per meter cubed. It can count particles of different sizes, like PM2.5 and PM10, and record that information every 15 seconds. It is possible to count particles of different sizes one by one, but what we care about is the total amount of particles. The total of all the pieces of different sizes.
When we’re done with the basics, we run our tests by turning on the particle counter and leaving it on all the time. After setting up the air filter and making sure it’s properly sealed, we make a 5-gram smoke bomb that is lit using the firing port. When there are more than 580 million particles per cubic meter of air in the room, we turn on the air cleaner. With the data from the Temtop, we can properly and real-time track how the air filter affects the particle count.
In normal situations, like when there was no smoke in the test room, the Temtop recorded a total particle count of about 10 million. Think of this as the “finish line” for this race to get rid of particles. For our test, it was better if the air filter could get the particle count back below 10 million per cubic meter as soon as possible. We do this test twice, once with the fan set to the lowest level and again with the fan set to the highest level, to see how well each unit works in a range of conditions. See what happened with each unit we tried when the fans were set to low and high in the GIFs below:
Checking the level of noise
That being said, this test is easy but tells you a lot. With a decibel meter, we check how loud the air filters are when the fan is set to low, medium, and high. If you want to leave your air filter going all night in your bedroom without waking you up, this is especially important.
This test is done in our sound-improving lab to make sure that the decibel meter only picks up soundwaves from the air filters and not from any other source. This number tells you how loud the air cleaner is. Based on the line below, each unit we tried measured around 35 decibels at its lowest setting. However, there was more of a difference between them at middle and high levels.
Using up energy
For people like me whose allergies are the worst, having an air filter on all the time is fine. Your energy price will definitely go up, which is the only thing that worries me. How much more, though?
To find out, we use a tool called Kill-a-Watt to check how much power each air cleaner needs at various fan speeds. So, we can figure out how much it would cost each month to run the unit nonstop. The price of electricity per Kilowatt-hour in your state is all you need to know. It’s best explained by the following formula:
power used/1000 * 24 hours * 30 days * average energy cost per KWh in your state = average cost to run an air filter nonstop for a month
In different states with different energy rates, the chart below shows how much it would cost to run each air filter for one month on its highest fan setting.
We’ve also tried other air filters
This is the smallest and least expensive one in the group. It has a 3-stage filter system and lets you add essential oils for massage, which is great. Poor showing at the bottom of the table, sadly.
Mediify MA-25: This machine didn’t work well enough to support the price. We had trouble testing how well it got rid of particles, and it was the loudest small air cleaner we looked at.
The Kenmore 850e has a three-stage filter system that does a good job of getting rid of particles. It also has a tablet monitor and an adjustable night light. It wasn’t quite as good as our top pick for small areas, the BlueAir Pure 511, but at $100, it’s a good option on a budget.
GermGuardian AC4300 has a HEPA filter with an extra antibacterial agent, an activated charcoal filter, UV-C light as a germicide, and a light that lets you know when the filter needs to be changed. Although, it did about average.
Our runner-up for medium-sized rooms is the Levoit Core 400s. We tried a lot of medium-sized air purifiers, and this one was the most expensive and best in every way. Wi-Fi connection, voice control, and the VeSync app let you check the air quality and manage the unit from afar. It works with Google Assistant and Alexa too.
The only things that stand out about the Veva 8000 are how cheap it is and how quiet it is. It did the worst in our test of particle cleaning and also in our test of how well it used energy.
As for how well the TruSens Z-2000 removes particles, it’s not very good. It has a UV-C light and an air quality indicator, which make it a good choice for the price.
Coway Airmega AP-1512: Overall, it works better than average. It has a color-coded air quality indicator, an eco-mode, filter alerts, and an ionizer option that makes getting rid of germs and viruses even better.
Cleaning Force CP-Rainbow: This unit did a great job, I was pleased. At the highest fan setting, it was the fastest air cleaner at getting rid of particles. It got rid of all smoke particles in just 1 minute and 45 seconds, which is amazing. It has a color-coded display and an HD LED screen for checking the air quality. You can control it with an app or your voice. Just a few features less than our top pick for the best air filters for big rooms, but it costs a lot more, which is why it’s not at the top of the list.
The Coway Airmega 400S works well enough and has a very advanced filter system. It can be controlled by speech or an app, and the app can measure the air quality. The machine also has color-coded LED signs. Truth be told, there are better deals out there.
The best thing about the EnviroKlenz Mobile UV is that it has two UV-C lights that kill germs and viruses in the air. It’s pretty big and heavy, too—40 pounds, just saying. In our particle removal test, it took the longest to clean the air, and it costs a lot to buy and run.
You might have heard of a different air filter called Molekule. It made news in 2017 for its sleek form and unique filtration technology. The Molekule, on the other hand, makes things more difficult: The company that makes it says that its special PECO air filter gets rid of particles in the air that are much smaller than 0.03 micrometers. But because it filters air so slowly, even if the company’s claims are true, it doesn’t clean the air as well as HEPA models do (as Consumer Reports pointed out in its very critical review).
The $500 Molekule Air Mini Plus has these issues, and we don’t suggest it right now. This is because of these issues and the National Advertising Review Board’s decision in 2020 to make Molekule to withdraw many of its false advertising claims. Still, the air filter seems to deal with a problem that most HEPA filtration cleaners don’t: gaseous pollutants in the home. Many things, like paint, furniture, cleaning products, and even some plastic boards, can release these kinds of pollution. Just because of that, Molekule’s catchy name is worth keeping an eye on, especially since the company combined with AeroClean in October 2022 to form AeroClean.
The problems that Dyson’s gadgets solve are related but not exactly the same. We’ve tried some of its air purifiers before, like the Dyson Pure Cool TP04, which has a HEPA filter but no CADR. According to a Dyson representative, “CADR as measured by some current methods is not an accurate representation of a real home.” That’s why the company has come up with its own testing methods “to replicate a more realistic setting.” One of these is a testing room with nine sensors placed around the space instead of AHAM’s single sensor and an area that is more than twice as big as AHAM’s testing rooms. Dyson’s own tests show that the Dyson TP04 works well, which may not come as a surprise.
There are a few extras that come with the Dyson TP04 air purifier. It has a moving fan to help move clean air around larger rooms, an app that gives you information about your home’s air quality, and a small but cool display. But is the big price increase really worth it? When we test it in our new test room, we’ll have a much better idea, but until then, we think there are better values out there.
How do air purifiers and HEPA filters work?
“High Efficiency Particulate Air” (HEPA) is an acronym for a type of filter that is defined by the US Department of Energy to remove certain sizes of particles from the air. It does this by using a web of linked glass threads to catch the particles. Models of HEPA air purifiers use fans to pull air into the machine and catch tiny particles like dust, germs, viruses, pollen, smoke, and mold. The clean air is then sucked back into the room through a vent. The US and European HEPA standards are not the same. The US standard says that HEPA filters must remove 99.97% of particles 0.3 microns or larger from the air. On its website, Coway has a great explanation of this kind of filter.
Do air purifiers increase or decrease oxygen in the room?
There is no change in the amount of oxygen in the room caused by air filters. The air in the room is cleaned by your air cleaner by moving it and running it through a filter that gets rid of tiny solid particles. It’s not taking air out of the room or adding more of it. Also, air purifiers and stand-alone air conditioners are not the same thing. However, the improved airflow from an air filter may make the air in your home noticeably cooler.
Where is the best place to put an air purifier?
To begin, you should make sure that the room where you put the air filter is big enough to handle it. If you want to clean the air in the room most effectively, put it in the middle of the room. So that people don’t trip over it, though, you can put your air filter somewhere less obvious. Just make sure that you know where its intake and exhaust vents are and that they aren’t blocked. Putting your air filter near doors and vents that move air may help it work better.
How often should I change the filter on an air purifier?
How often and how fast you run your air cleaner are some of the things that determine how often you need to change the filter. Another factor is how dirty the air is to begin with. Most air filters have more than one filter. They usually have a prefilter and a HEPA filter. The prefilter, which can sometimes be washed, is used to catch big things like pet hair. By taking good care of the prefilter, you can make the HEPA filter last longer. Most of these brands say that the filter should be changed every six months. Some say once a year, but it really depends on the size of the HEPA filter and the prefiltration system. You can often buy new filters and prefilters at the same stores that sell air purifiers, or you can buy them on the websites of the brands. Some websites offer cheap membership plans for replacement filters.
Do air purifiers prevent the spread of diseases such as COVID-19?
Yes is the short answer. HEPA air filters remove virus particles from the air by catching them. You can use an air filter, but it won’t protect you from virus particles if you live with someone who is dangerous. In 2022, tkgap talked to Richard Shaughnessy, who was the head of indoor air studies at the University of Tulsa. He said that COVID is generally spread by being close to someone who has it. An air filter across the room won’t get rid of all the germs someone who is sick breathes out before they can reach you if you’re sitting on the couch and talking to them.
