Amanda Blum
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Amanda Blum
Freelance Writer
Freelancers cover news, tech, and entertainment for Lifehacker.
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Our Top 5 Picks
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If You Also Need a Fan and HeaterDyson Purifier Hot+Cool
$435.00
at Amazon
$435.00
at Amazon
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Best For Design FanaticsMila Smart Air Purifier
$299.99
at Amazon
$299.99
at Amazon
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Best for Small RoomsAirThings Renew Smart Air Purifier
$299.99
at Amazon
$299.99
at Amazon
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Has a Fan, Is LargeDreo Smart Air Purifier Tower Fan
$329.99
at Amazon
$329.99
at Amazon
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Best For Mid- to Large-Sized RoomsCoway Airmega IconS
$598.12
at Amazon
$598.12
at Amazon
Why get an air purifier? Take your pick: There’s smoke from widespread fires, airborne viruses, dander from pets, and the generally poor air quality from car emissions. If you’re looking to invest in an air purifier, I’d argue that getting a smart purifier is the better bet.
This new class of air purifiers are wifi-enabled and usually have a corresponding app allowing you to turn the purifier on and off remotely or as a result of triggers through an automation. They also tend to give you more detailed information on what they’re pulling out of the air, and best of all, can tell you precisely when to replace the filter. Usually, the rule is every six months, but that depends on how much use your purifier has seen and the conditions it has been under. The price of those filters can add up over time, so knowing more precisely when to replace them means you’re getting the most out of your purifier.
I’ve tested all the air purifiers on this list and like them all a lot—the important thing is to determine which one is best for you. I’ve outlined a few factors to consider below.
What types of filtration to look for
Most purifiers have a series of filters, including a pre filter (which removes bigger particulates like dust or pet hair), a HEPA filter, and a carbon filter. While we focus a lot on HEPA filters, HEPA won’t do anything about VOCs, odors, and gases; that’s what you need carbon for.
How powerful of a purifier should you get?
Most purifiers say right on the label how big a room they are meant for, but this is expressed in square feet; since purifiers treat the air in a room, this math should take into account the cubic feet of air in a room, which takes the height of the room into account, too.
According to Mike Feldstein, founder of Jaspr, a smart air purifier company, there’s another factor you should take into account. What you really need to know about your air purifier, he says, is how much air it moves and how quickly it does so, because this will allow you to figure out how many exchanges of the air in a room you’ll achieve in an hour. For the average home, four to eight exchanges an hour is good, says Feldstein. (For medical settings, you want 10-15 exchanges.)
How fast the air moves is referred to as CADR (clean air delivery rate) and the CADR number indicates how many cubic feet of air are moved per minute. If it’s not in the product manual, you can usually search for the product specs online and find that info there.
So, how do you apply that to your room? You’ll have to do a little math. Take the CADR from the purifier specifications and multiply it by 60 (60 minutes in an hour). Now divide that by the volume of your room (height x length x width). For instance, if the CADR is 430 and your room is 10’x10’x15′, the math is:
(430*60)/(10*10*15), which simplifies to or 25,800/1,500, which is 17.2.
That result is your ACH (air exchange per hour). That means the air in the room is exchanged 17.2 times an hour, well more than is necessary. In this case, the purifier can accommodate a much larger space, or will be fine on a lower setting.
Location counts
Purifiers shouldn’t be hidden or tucked against walls. To work their best, they need to be in the center of spaces. This can be frustrating, since purifiers have cords that can be tripped over. For that reason, it may be worth considering purchasing several smaller purifiers that can live on tabletops, instead of bigger floor units in fewer locations.
Table of Contents
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If You Also Need a Fan and HeaterDyson Purifier Hot+Cool
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The Good
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Also has a fan and heater -
Good-looking and solidly built
The Bad-
The smart app is incredibly limited -
Doesn’t filter as well as dedicated purifiers -
Mostly requires a physical remote
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- Three-step filter including HEPA
- Night mode purifies using the quietest settings, with a dimmed display
Get It Now -
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Best For Design FanaticsMila Smart Air Purifier
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The Good
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Choice of filters can let you target specific pollution (VOC, pollen, dust, virus) -
Clean, modern design, tucks away easily -
Very clean app design
The Bad-
Filters are far more expensive than other brands.
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- Seven different filter options
- CADR of 416 m3/hr
- Three levels of filtration
Get It Now -
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Best for Small RoomsAirThings Renew Smart Air Purifier
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The Good
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The quietest purifier I tested. -
Cleans better than other purifiers -
Integrates with whole line of AirThings monitors and sensors
The Bad-
King of ugly -
Smaller capacity than other similarly priced purifiers
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- Four-stage cleaning
- CADR of 140 cfm
Get It Now -
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Has a Fan, Is LargeDreo Smart Air Purifier Tower Fan
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The Good
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It’s also a Dreo fan, with spectacular “natural” cooling patterns. -
Heavy enough thta you won’t knock it over -
Fan is elevated
The Bad-
It’s huge -
Covers a small area
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- CADR of 60
Get It Now -
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Best For Mid- to Large-Sized RoomsCoway Airmega IconS
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The Good
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Enjoyable app experience -
Voice control -
Integrates with other home hubs
The Bad-
Louder than most purifiers -
Expensive
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- CADR of 195
- Automatically adjusts settings in smart mode
- Three-stage filtration
Get It Now -
If you take the time to do the math on the space you’re trying to purify, and ensure that the filter you purchase is well placed in the room, a smart purifier will do the rest of the work for you. It will even notify you when it’s time to change the filters. I’ve tested all of the air purifiers on this list, and any will be a solid choice; it’s just a matter of figuring out which is the best for your home.
What do you think so far?