Coway AP-1512HH Vs Alen FLEX – In-depth Comparison in 2022

Coway AP-1512HH and Alen BreatheSmart FLEX are medium-sized air purifiers with high-quality filters and outstanding performance.

Coway covers rooms up to 361 sq. ft. It has plenty of advanced options from which I would single out the air quality sensor and auto mode. Alen is intended for rooms up to 300 sq. ft. Unfortunately, it can’t boast advanced options such as an air quality sensor or auto mode. I want to emphasize that both devices clear the air 4.8 times in one hour in the rooms of the recommended dimensions.

Coway AP-1512HH Vs Alen FLEX - Air Purifiers Comparison

Before moving on to a detailed comparison, I just want to add that both devices use a True HEPA filter and that Alen FLEX uses a high-quality carbon filter.

Coway AP-1512HH Vs Alen FLEX Specifications

Alen FLEX Air Purifier Coway AP-1512HH Air Purifier
Manufacturer Alen Coway
Model BreatheSmart FLEX AP-1512HH
Dimensions 8.5 x 15 x 25 inches 16.81 x 9.65 x 18.30 inches
Coverage (4.8 ACH) 300 sq. ft. 361 sq. ft.
Filtration Technology Pre-filter, True HEPA Filter, and Activated Carbon Filter Pre-filter, Deodorization Filter, and True HEPA Filter
Filter Replacement Indicator
Filter Longevity 9-12 months up to 12 months
Power Consumption 50W 77W
Smart Sensor
Auto Mode
ECO Mode
Air Quality Indicator
Warranty Lifetime 3-year
In-Depth Review Alen FLEX Coway AP-1512HH
Price Check Price on Amazon Check Price on Amazon

Coway Vs Alen Features

As I indicated at the beginning of the comparison, the Coway AP-1512HH has much more advanced options than Alen FLEX so I will devote more time to Coway in this section.

Coway AP-1512HH Vs Alen FLEX Air Purifiers - Controls
Alen FLEX and Coway AP-1512HH have controls located on the top.

What is the most important when it comes to features is that both devices have quite enough options for optimal daily use.

Air Quality Sensor and Indicator

An air quality sensor is an option that is only available on the Coway AP-1512HH. This sensor is located on the side of the device and detects dust particles in real time.

The sensor works in combination with other options, such as the air quality indicator. It is located on the top of the device and lights in a different color depending on the current air quality.

What I really like is that Coway offers the option to adjust the sensor’s sensitivity.

Auto and ECO Modes

In addition to the air quality indicator, the air quality sensor works in combination with Auto Mode and ECO mode options.

Basically, when in Auto Mode, the air purifier will switch the mode depending on the current air quality.

ECO mode is similar to Auto Mode, except that ECO mode turns off the air purifier if the air is excellent in the last half hour and turns it on again if the air worsens.

Filter Reset Indicator

Fortunately, both air purifiers use a filter reset indicator.

Essentially, the filter reset indicator will notify you when it is time to replace the filter, and in this way, you will not have to monitor when you need to change the filter manually.

All in all, this is a very useful option.


A timer is an option available on both devices. Essentially, the timer is used to set the time for when you want the device to shut down.

On the Coway AP-1512HH, the timer can be set to 1h, 4h, or 8h, while on the Alen FLEX, the timer can be set to 2h, 4h, or 12h.


These two air purifiers have a very similar construction, which is why both devices have air intake vents on the front.

On both air purifiers, filtered air exits through openings on the top.


Regarding the warranty, I have to say that Alen FLEX has surpassed Coway AP-1512HH here because it comes with a lifetime warranty.

Coway, on the other hand, comes with a 3-year warranty, which is quite ok.

Alen FLEX Vs Coway AP-1512HH Video Comparison

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Filtration Technology

As these two are top-notch air purifiers, it’s somehow expected that they have high-quality and extremely efficient filters. Luckily, I did performance tests on these two air purifiers, in which I confirmed that they have incredibly efficient filters. 

Coway AP-1512HH Vs Alen FLEX - Filters Comparison
Coway and Alen filters comparison.

The Coway AP-1512HH uses 4-stage filtration consisting of a washable pre-filter, True HEPA filter, activated carbon filter, and ionizer. What’s good is that the ionizer is turned off by default, so if you don’t feel like you don’t have to use it. In addition, Coway is CARB certified, which means it does not produce unallowed amounts of ozone.

Alen FLEX uses 3-stage filtration technology consisting of a pre-filter, True HEPA filter, and an activated carbon filter. I like Alen because it offers as many as three different filter options, and the most massive filter contains as much as 2+ lbs of carbon pellets.

I want to mention that Alen has slightly thicker filters, but they don’t last longer than Coway’s.

How to Replace Filters?

Since these two air purifiers do not use washable filters, except for the pre-filter on Coway, it is necessary to change the old filters from time to time.

That period averages about 12 months for Coway and between 9-12 months for Alen. It is commendable that both devices use a filter reset indicator, so you will not have to monitor when it is time to replace the filter.

I have described the detailed process of replacing the filters in the individual reviews that you can find at the links below.

How to replace Coway AP-1512HH filter? How to replace Alen FLEX filter? Filter replacement

Noise Tests

Regarding the noise test, I want to say that Alen has 4 fan speeds, while the Coway has 3. As the Alen FLEX is one of the quietest air purifiers I have tested so far, the Coway doesn’t have many chances of winning this test.

Let’s compare their noise levels at the first and max speeds to prove this claim. Coway AP-1512HH produces a sound of 41.4 dBA on the first speed, while the Alen FLEX produces a sound of 41.2 dBA. The situation is much more different on the max speed, where the Alen produces a sound of 53.7 dBA, and the Coway produces a sound of 63.5 dBA.

Product Noise Range (dBA)
Coway AP-1512HH 41.4 – 63.5 dBA
Alen FLEX 41.2 – 53.7 dBA

Obviously, the Alen FLEX is a much quieter air purifier than the Coway AP-1512HH.

Performance Tests

As for the performance test, I tested these two devices in rooms of different dimensions. I believe the Alen FLEX has a very good predisposition, and that’s why I tested it in slightly larger rooms than the Coway AP-1512HH.

Coway AP-1512HH Vs Alen FLEX Air Purifiers - Comparison
I used a laser particle meter to test Alen FLEX and Coway AP-1512HH performance.

In the test in a room of 560 sq. ft., for 60 minutes of operation at max speed, the Alen FLEX improved air quality by an incredible 94%. On the other hand, I tested the Coway AP-1512HH in a 320 sq. ft. room, where it improved air quality by an even more incredible 96% in just 60 minutes of operation at max speed.

Although these tests were performed in different room sizes, we can easily conclude that Alen FLEX and Coway AP-1512HH have made fantastic results and have proven why they are top air purifiers and one of the best in class.

Operating Costs

When we talk about operating costs, the first thing I want to compare is the power. The Coway AP-1512HH has a 77W motor, while the Alen FLEX has a 50W motor.

This means that if you left these two devices running at max speed, 24 hours a day, for a period of one month, your electricity bill would be increased by about $2.1 in the case of Alen FLEX and by a much higher $6 in the case of Coway.

Product Wattage Range (W)
Coway AP-1512HH 0.2 – 69.1W
Alen FLEX 0.4 – 24.3W

Suppose we add to that the price of replacement filters which, although slightly cheaper in the case of Coway, do not make much of a difference in this test. We can say that the Alen FLEX is more maintenance-friendly than the Coway AP-1512HH.

Which One Does It Better?

I have to admit that this was a tough fight, and it was not an easy task to determine the winner. Although the Coway AP-1512HH is one of my favorite air purifiers, I would still give a slight advantage to Alen FLEX and declare it as the winner in this comparison.

The reasons are excellent performance, extremely high-quality filter, the possibility of purchasing various filter options, much quieter operation, and more affordable operating costs. All in all, these are two high-quality air purifiers, and even in case you opt for Coway, you won’t make a mistake at all.

If you have any questions, leave a comment in the comments box below.

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