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The Levoit Core 400S is a high-performance smart air purifier with a three-stage filter system that sandwiches a filter between a pre-filter and an activated carbon filter to capture 100% of airborne particles and reduce odors. It is also Wi-Fi enabled, allowing remote control via the VeSync app. It also features auto, sleep, and manual modes. The auto mode uses an air quality sensor to maintain the air quality, while the sleep mode reduces noise and dims the display. The compact and sleek design operates quietly at 55 decibels on the highest setting. Additionally, the display shows the air quality level and filter status. Despite the high cost of replacing the filter, we think the Core 400S is a good choice for home and office use, particularly when remote control and smart home integration are a must. Our article on the best air purifiers will show you how it fares versus competing products.
REASONS TO BUY
VeSync smart app
Air quality sensor
Three-stage filter
REASONS TO AVOID
Some features only accessible with app
Expensive replacement filter
No Longer Labeled True HEPA — January 2024
Levoit previously claimed their Core series, including this 400S model, contained a True HEPA filter. After a recent challenging by Dyson, Levoit voluntarily removed the True HEPA title from these products. We still find the performance of this model to be quite good, but if you want the True HEPA filter, you will need to look to another model.
*Per Levoit, their stated CADR ratings for this product are the same for Smoke, Dust, and Pollen but differ for fan speeds
234 (Smoke)
248 (Dust)
232 (Pollen)
250 (Smoke)
250 (Dust)
250 (Pollen)
141 (Smoke)
140 (Dust)
145 (Pollen)
40 (Smoke)
40 (Dust)
40 (Pollen)
Measured Dimensions
10.8" x 10.8" x 20.5"
9.6" x 16.8" x 18.3"
12.5" x 12.5" x 19.0"
8.7" x 8.7" x 14.2"
7.9" x 7.9" x 12.6"
Measured Weight
10.4 Ibs
13.1 lbs
7.9 Ibs
7.3 Ibs
5.4 Ibs
Measured Cord Length
6' 3"
6' 6"
7'
6' 3"
5' 10"
True HEPA
(99.97%)
No
Yes
Yes
No
Yes
Estimated Lifetime Cost (5 years)
$740.70
$550.81
$721.50
$484.03
$423.93
App Control
Yes
No
Yes
No
No
Air Quality Sensor
Yes
Yes
Yes
No
No
Measured Decibels
51.8
55.9
49.2
52.3
46.1
Energy Star Certified
Yes
Yes
Yes
Yes
Not Listed
Listed Coverage
1560 sq. ft
1,748 sq. ft
1,800 sq. ft
219 sq. ft
129 sq. ft
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Our Analysis and Test Results
Performance Comparison
This air purifier's interface is user-friendly, intuitive, and effective.
Credit: Abriah Wofford
Air Cleaning Performance
The Levoit 400S does a fine job cleaning the air in rooms up to 1560 square feet. While the unit's clean air delivery rate (CADR) of 260 isn't the highest in the class, it's pretty good considering the size of the unit and the other features it offers. For example, the 400S has an air quality sensor that will automictically turn on the unit when airborne particulates reach an undesirable level. All told, our air cleaning performance test revealed that the 400S is one of the leading performers in the class.
Our air cleaning performance test involves burning five sheets of printer paper in a 150-square-foot room with an 8-foot-high ceiling. We place a Dylos air-quality meter in the room and measure the number of particulates removed at 30, 45, and 60 minutes. The 400S went from a particulate reading of 35,458 to 242 in the first 30 minutes. This particulate count was reduced to 14 particles at 45 minutes and next to nothing at 60 minutes. That's about a 100% difference in an hour, representing one of the class's highest performances.
With a clean air delivery rate (CADR) of 260, the 400S moves a lot of air for its relatively compact size.
Air purification isn't the only component of our air cleaning performance metric—we also factor in odor removal. As it turns out, this task is much more demanding than removing harmful particulates from the air. Moreover, smoke proves to produce a particularly insidious smell. At the beginning of our smoke test, the odors were very strong. However, the scent grew progressively less intense throughout the test. By the end of testing, the air smelled much better though a mild, acrid odor was still detectable.
This top performer cleared the testing room of large particles in a remarkably fast time. By the 30 minute mark, the large particle count decreased from 35,458 to 242. By 60 minutes, the large particle count read as 1. Impressive!
Credit: Genaveve Bradshaw
We also liked that the 400S automatically powered on when we started burning paper for the test. For one, this result shows that the air quality detector works. In a real-world scenario, this feature would help prevent the build-up of airborne particulates and odors.
In our tests we burned paper and incense in a controlled space to produce both large particulates and pungent odors, then used a Dylos to measure those air particulates until the air purifier removed every last one.
Credit: Abriah Wofford
Noise
While cleaning the air in a home or office is the most important feature when shopping for a new air purifier, one does not want the unit to sound like an industrial fan running in the living room. The 400S isn't a bit louder than we liked when set to high and we measured 51.8 decibels. But, its fan is almost undetectable when set to low. The unit also offers a sleep mode that dims the interface lights and further reduces fan noise. All told, the noise output of this device is roughly average for the class.
We use a sound pressure level meter to measure the decibel output of the air purifiers. However, as many readers will know, the volume of a given noise is not always as important as the type of noise. As such, we also consider whether the 400S is particularly annoying or distracting. For the most part, the 400S produces soft noise. However, when set to high, the fan issues a noticeable whir. At its medium setting, the fan noticeably decreases in sound output. And, at the low setting, the noise is barely detectable.
The 400S has an average sound output that decreases with the fan setting. When put in sleep mode, it hardly makes any noise at all.
Credit: Genaveve Bradshaw
Ease of Use
When it comes to a new purchase, the product's ease of use is often overlooked in the effort to see if the product will do its intended job. Yet, even if an air purifier cleans the air quite well, it will be a less-than-satisfying purchase if it is a pain to use. Fortunately, the 400S is a remarkably easy machine to use. Moreover, this ease of operation comes without sacrificing features to simplify the interface and settings.
To begin, we look at how easy it is to set up the air purifier. With the 400S, this process takes about five minutes. One simply opens the canister (no tools needed), unwraps the filter, puts it back together, and plugs it in. The companion app allows for remote access, additional settings, and information such as the unit's run time, the number of square feet of air purified, and the percentage of the filter used.
This unit is mid-sized compared to most air purifiers.
Credit: Abriah Wofford
The app allows users to set the air sensor and turn the device on and off when the desired thresholds are met. This app is a cinch to download and use. As for the 400S's control interface, it is quite simple and intuitive. For example, correlated images represent the touch buttons' functions, such as touching the crescent moon, which sets the unit to sleep mode. Lights and a digital display let the user know which functions are active.
The 400S has a very intuitive user interface with easy to identify buttons and easy to navigate settings.
Credit: Abriah Wofford
Finally, we look at the unit's portability since some will want to move their air purifiers around. The 400S weighs 10.4 pounds. It is 20.5 inches tall and has a diameter of 10.8 inches. Compared to the other units in the class, the 400S is quite easy to transport, particularly given its inset handles and compact barrel shape.
The Levoit Core 400S weighed in at 10.4 pounds.
Credit: Natalie Kafader
Operating Cost
Like the details of the ease of use metric, the long-term cost of an air purifier can be easy to overlook. Unfortunately, the same filter that produced such good outcomes in the air purifying metric results in a high operating cost. However, the energy consumption of the unit is quite low. Our calculations indicate that the 400S will only cost $3.00 annually if run on its medium setting. However, the filter in the unit is rated to last 6-8 months, adding $100 to the annual operating cost.
Should You Buy the Levoit Core 400S?
The 400S is a great value when looking at its cost-to-performance ratio. Few air purifiers offer consumers the app-controlled features and air purifying capacity of the 400S at such a competitive price. Simply put, you can't go wrong with this device if it's within your budget. Moreover, the unit fits well with various home and office stylings and decor.
What Other Air Purifiers Should You Consider?
The Levoit Core 400S is a top-notch device that removes 100% of airborne particles through its three-stage filter system. The unit's sleek, compact design operates at a relatively quiet 55 decibels and can be controlled remotely via the smartphone app. All that is to say, the 400S is a hard to beat smart device — especially for the price. However, if long-term costs are a concern, consider the Coway Airmega 200M. This unit has a HEPA filter and similar CADR to the 400S but has a long-term operating cost of roughly half the 400S. The up-front cost is lower as well. However, one loses the smart controls in the bargain.
If you want a smart air purifier and a higher CADR, then the Coway Airmega 400S is the ticket. This unit has a CADR of 328 for smoke and dust, a HEPA filter, and an accompanying app. However, be prepared for serious sticker shock and hefty long-term costs.
