The Best Air Purifier

Breathe a little easier

The 30-Second Review

The best air purifiers have a few things in common: a true HEPA filter, a secondary charcoal filter to help capture odor, and a stamp of approval from the Association of Home Appliance Manufacturers. AHAM is the organization that tests air purifiers and evaluates how good they are at removing dust, pollen, and tobacco smoke from the air. It's also the company that determines just how large a space a unit can effectively purify. We looked for the best at cleaning a 360-square-foot room, which is slightly larger than the average master bedroom.

Our Top Pick

Lightweight and quiet, this purifier is regularly up to $100 cheaper than the Coway, with better construction. ($160-190 on Amazon)

A Close Runner-Up

Equally lightweight, quiet, and effective as our top pick. If you prefer the looks of the Coway, it's a great choice. ($230 on Amazon)

Pop quiz: What’s dirtier — the air inside your home or the air outside of it? According to studies conducted by the Environmental Protection Agency (EPA), the air inside a home might be two to five times more contaminated with pollutants, be it animal dander, cigarette smoke, or soot.

Enter the air purifier. They can be hugely beneficial for allergy and asthma sufferers, as well as anyone who lives near major highways or other pollutant-filled areas, like coal plants. The best ones use fans to cycle air through a series of filters, capturing impurities and jetting clean air back into the room. Choosing the right air purifier comes down to the types of filters it has — a true HEPA is key — and making sure it can accommodate the size of the room you want cleaned.

We have two favorites best suited for rooms measuring about 360 square feet (a little larger than the average master bedroom) and they are neck-and-neck in both performance and price. The Winix 5500-2 Air Cleaner is our top pick due to slightly better construction and a lower price tag, but if you prefer the looks of the Coway 4-Stage Filtration System, we won’t dissuade you. It’s flimsier, but is rated to clean the air as well as the Winix — and because of cheaper replacement filters, it will end up saving you more long-term.

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Our top pick, the Winix 5500-2, at left, compared to the bubblier Coway.

CADR Ratings for Our Five Test Units

Max Square Footage

CADR Pollen Score

CADR Dust Score

CADR Tobacco Smoke Score

Winix 5500-2 (Top Pick)
360
246
243
232
Coway 4-Stage Filtration System (Runner-Up)
360
240
246
232
GermGuardian® AC9200WCA
378
346
310
244
Winix True HEPA U450 Air Cleaner
450
343
298
291
Honeywell HPA300
465
300
320
300

Our Picks for the Best Air Purifier

Our Top Pick

Winix 5500-2 Air Cleaner with PlasmaWave Technology It was nearly a tie with our runner-up, but this air purifier is cheaper up front and boasts better construction.

To be honest, choosing between the Winix 5500-2 and our runner-up, the Coway 4-Stage Filtration System, will come down to aesthetics. When it comes to performance, they are similar. Long-term, the costs even out. Even the chimes when you push a button sound the same. We had a hard time choosing a favorite, but the Winix eked out its top spot due to lower up-front costs and higher quality construction.

Both have nearly identical pre-filters, true HEPA filters as their primary purifiers, and some sort of charcoal filter to absorb odor. (The Winix has little pockets of charcoal nubs; the Coway has charcoal foam, like what you get in your kitchen compost bin, or on top of a litter box.)

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The Coway (top) has a nearly identical filtering system as the Winix (bottom).

They are virtually silent on their lowest settings and registered between 61 and 64 decibels at their loudest — about the equivalent of an air-conditioning unit set 100 feet away. Both have timers and sensors that measure air purity, with glowing LED lights that shift from blue to red the more polluted the air. On its Auto setting, the Winix automatically runs the fan at its lowest when the air quality is good; similarly, the Coway’s Eco setting shuts off the fan altogether when it deems it unnecessary.

A Very Close Runner-Up

Coway 4-Stage Filtration System with Air Quality Indicator A more petite purifier also rated for 360 sq. feet, and with the cheapest filters we saw. Long-term, this one is the better deal.

See? Pretty much same-same.

There are a few differences. Both purifiers also have ion filters you can turn on and off, but where the Coway advertises that its Vital Ion filter only “freshens the air” with negative ions, the Winix touts bamboozling proprietary PlasmaWave Technology, which, when activated, claims to “instantly neutralize airborne viruses, bacteria, chemical vapors, odors, and gases” (!!!). We didn’t really take this particular piece of marketing seriously — in fact, if it had jacked up the price, we likely would have skipped recommending the Winix altogether.

But, it turns out, the Winix is typically priced at least $50 cheaper than the Coway, and we’ve seen it retail for nearly $100 less on Amazon and Home Depot.

Other than price, the differences boil down to looks and maintenance — and even those are nit-picky. We prefer the matte charcoal Winix to the glossy Coway, which was a magnet for cat hair and dust. And even though the Coway is cuter in an alien-TV sort of way, the taller, slimmer Winix ended up a more discreet room addition.

Popping the hood of the Winix was easy. The cover uses magnets to snap in and out of place, and each filter locks inside the next — there’s no question where each piece should be when you’re taking it apart and then putting it back together to replace the filters. The Coway is much flimsier, and it takes a couple of tries to put the front back on after you remove it. It’s not a deal breaker, but if you’re taking it apart every two weeks to rinse out the pre-filter (which is recommended for both units), the Coway is more of a hassle.

How Larger — and More Expensive — Air Purifiers Stack Up

The three other air purifiers we looked at retail for between $300 and $440, which is significantly more than the $150-$250 range of our top picks. Shelling out that extra cash is going to get you two things:

  • A larger unit with a bigger filter that can purify more square footage (worth it if you need it).
  • The potential for some bells and whistles that may or may not work (not as worth it).

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From left to right: The Winix U450, the GermGuardian AC9200WCA, the Honeywell HPA300, the Winix 5500-2, and the Coway 4-Stage Filtration System.

In some cases, looks and construction may also improve a bit. The Winix U450 ($440) is sleek and glossy white, and its filters fit into a frame, unlike the Winix 5500-2, whose filters you just stack one on top of the other inside the unit. But what you’re really paying for is 450 square feet of coverage — a full 100 more than the Winix 5500-2 — and a pre-filter treated with something called “Antimicrobial CleanCell Protection,” which supposedly helps reduce the development of bacteria, fungi, and mold. We’re not convinced. If you’re worried about bacteria, we think you’re better off putting two Winix 5500-2 units in opposite corners to make up for the square footage and using the leftover $60 to stock up on hand sanitizer.

The GermGuardian AC9200WCA ($360) squeaks out 18 extra square feet in coverage than our top picks, but makes up for it in early-’90s Apple aesthetics and doubling down on germ phobia. The GermGuardian includes UV-C light technology, which works to eliminate microbes — but the jury is out on how effective UV filters even are. Puri says there is no science backing their efficacy in air purifiers, but Marc Rubin, a registered pharmacist and board member of the Chicago Asthma Consortium, thinks they may be worth it. “UV combined with HEPA has a greater value in that it may kill airborne organisms and mold,” he told us, “it is important that the product allows access to the UV light for cleaning, since dust buildup diminishes the effective potential of the unit.”

In some cases, the cost corresponds exclusively to size. Honeywell was consistently recommended by our experts, and the Honeywell HPA300 ($300, although we found it for around $180 on Amazon) excels on paper. Its CADR ratings — 300 for pollen, 320 for dust, 300 for tobacco — qualify it for a room up to 465 square feet, the most coverage of all five we looked at. With this guy, you’re really only paying for size, nothing fancy. It has a cheap-looking plastic grille we nearly snapped in half trying to take on and off, an unresponsive touch panel, and the same charcoal and HEPA filters as our top picks. It’s also more hands-on, with no auto or eco setting like our top picks; you have to select what fan speed you want, and manually adjust it. But there’s no denying its exceptional ratings and the amount of square footage it can cover.

Did You Know?

For long-term costs, factor in replacement filters and energy use.

Air purifiers aren’t a one-and-done purchase — replacement filters and energy use will affect your bottom line, especially considering that air purifiers are typically left on all the time to do their thing. Figuring out how much you’ll be shelling out takes some fast math.

To predict your electric bill, you need to know how many kilowatt-hours your purifier uses per day, multiplied by the average electricity rate where you live. Let’s use our top pick as an example: The Winix 5500-2 runs at 70W, or 1.68kWh. Denver electricity runs is 11.05 cents per kilowatt-hour. To run the Winix 5500-2 all day every day for a year, you’re looking at about $68 a year added to your electric bill.

Replacement filters are less complicated. The Winix HEPA filter is about $80 a pop; the Coway is closer to $50, and you replace each about once a year.

Winix 5500-2

Coway 4-Stage Filtration System

Upfront Cost
$190
$230
Replacement HEPA Filter
$80
$50
Cost to Run for 1 Year (Denver)
$68
$75
Total After 1 Year
$338
$355
Total After 5 Years
$930
$855

Because the Coway’s HEPA filters are such a good deal, the costs after a year are nearly negligible between our two top picks. After five years, the Coway may end up costing you less.

You can improve the quality of your air even without an air purifier.

A purifier can help mitigate pollutants in the air, but it won’t cure your allergies or rid your home of pet hair. It’s worth it to develop a few good habits to help keep air irritants out of the home.

  • Vacuum and mop your floors frequently.
  • Ask your guests remove their shoes before coming inside.
  • Don’t smoke or allow smoking inside your home.
  • Strive to keep your home’s humidity around 30–50 percent, which helps keep mold in check.

You can use a hygrometer to measure humidity levels, but there’s a simple way to do a quick check: If there’s fog and condensation on your windows, your home’s humidity level is probably too high and you may need to invest in a dehumidifier.

Last thing: Pet dander is especially tough to manage, even though it’s a common reason people purchase air purifiers to begin with. That’s because dander doesn’t stay airborne for long; it settles into carpets and onto walls and furniture before the air purifier has time to capture it. Keep dander at bay with regular bathing and brushing — and plenty of vacuuming. Feel your allergies flaring up at night? It might be worth it to keep those pets out of the bed while you sleep. (We know. Easier said than done.)

Placement is key.

Make sure your air purifier isn’t flush against walls or furniture, as most units work best when they can take in air from all sides. In a bedroom, situate the purifier roughly 6 to 10 feet from your bed (specifically, the headboard), with the registers facing you — this should help facilitate the flow of clean air toward you while you sleep.

“Air purifiers are especially critical during the sleeping hours when lung function naturally decreases, making the airways more susceptible to irritant inflammation.”

The Bottom Line

Our Top Pick

Winix 5500-2 Air Cleaner with PlasmaWave Technology A lightweight, quiet purifier that can effectively clean air in rooms up to 360 square feet.

CADR is king when it comes to air purifiers. It’s the only metric there is to compare units across manufacturers and styles, and all CADR ratings come with a maximum square footage they can effectively clean. Our top picks are both suited for 360 square feet — larger than the average master bedroom — but if you’ve got tall ceilings or a really open floor plan, you’ll be better off with a higher rating.