The stylish Alen BreatheSmart FLEX air purifier is unlike any you’ve ever seen. Developed by the NASA engineers, this classy device delivers the perfect balance between airflow and purifying performance unparalleled by most of its contenders. Plus, with a sleek, compact design, this air purifier would make the perfect addition to any modern home or office. Check out our full review of the BreatheSmart FLEX to see the numerous benefits this beast offers.

Alen BreatheSmart FLEX Air Purifier Review

Airflow and CADR Ratings

First things first: finding out whether the FLEX belongs in your home. This air purifier has a maximum purifying coverage area of 700 square feet, the ideal range for most kitchens, living rooms, and basements.

It has four different fan speeds that, from slowest to fastest, move up to 53, 135, 147, and 187 CFM of air. Its overall CADR in all three measurements (dust, pollen, and smoke) is an estimated 245 CFM – not the highest CADR ratings, but for its tiny size and lightweight build, we couldn’t be more impressed.

Compact and Lightweight

Speaking of its compact, lightweight design, there’s hardly a space where the FLEX doesn’t belong. Measuring in at 15 x 25 x 8.5 inches, this air purifier can sit in any corner of a room while discreetly cleaning the air.

Alen BreatheSmart FLEX Air Purifier

Alen BreatheSmart FLEX

It weighs only 15 pounds so transporting the unit up and down flights of steps is effortless. The carrying handle is located at the back right beneath the power cord.

Two-Stage Filtration

We’ve become accustomed to the standard three-stage setup of most modern air purifiers, but the two-stage filtration system of the FLEX is definitely not something to scoff at.

The first line of defense is a HEPA pre-filter – something we rarely see in residential-grade air purifiers – that removes larger particles from the air and prevent them from clogging the second filter where the magic truly happens. The second filter is a True HEPA Filter that stops invisible pollutants (dander, pollen, dust mites, etc.) up to 99.97% of the time.

Alen BreatheSmart FLEX

Alen BreatheSmart FLEX

Filter Selection

The True HEPA Filter that comes standard with the FLEX is the HEPA-PURE which mainly gets rid of dust, pollen, and other airborne allergens, but what about odors? Alen has the solution for you – HEPA-FRESH and HEPA-ODORCELL.

FRESH gets rid of light odors from cooking failures and light chemicals, whereas ODORCELL is a neutralizer for heavy-duty, nose-wrinkling from pets and dirty diapers. If you or a loved one is suffer from asthma, Alen’s HEPA-SILVER is the all-around solution filter that traps mold and airborne germs.

Basic Filter Indicator

In the back of our mind, we know that the HEPA filters need to be changed periodically. Even though each filter is designed to last up to a year with 25/7 use, the longevity of the filter varies from household to household.

Alen BreatheSmart FLEX Review

Alen BreatheSmart FLEX

Thankfully, Alen has eliminated most of the guesswork needed to determine when to change the filters by including an onboard filter indicator. The three LED lights will alert you of how clogged the True HEPA Filter is.

Almost Whisper-Quiet

In order for an air purifier to work discreetly in the corner of a room, it shouldn’t wake the dead by blasting loud sputtering noises. Thankfully, the FLEX doesn’t; in fact, it’s actually one of the quieter air purifiers for its size category.

Its noise production range is between 39 and 59 decibels – hardly louder than normal household background noises. Sadly, without an auto mode, the FLEX won’t switch to sleep/low-speed mode at nighttime but instead blast the music of its people at full-volume.

Alen FLEX Air Purifier Review

Alen BreatheSmart FLEX

Customizable Panel Options

Wouldn’t it be nice if your air purifier could match your home’s interior? Sure, a standard silver or black won’t clash horribly against most décors, but Alen takes it several steps ahead by providing a wide selection of designer panels of different colors and textures (sold separately).

As your tastes and home color schemes changes, the FLEX can develop along with you by detaching its standard silver panel and switching for something more color appropriate.

Child Lock

And to make the FLEX a lot safer around children and curious pets, it has a Child Lock button on the control panel. Of course, it won’t do anything to keep it from toppling over, but it will prevent it from turning off or making unwanted fan-speed changes.

Alen FLEX Air Purifier

Alen BreatheSmart FLEX

Related Alen Air Purifiers Articles
Single Reviews
Alen BreatheSmart FLEX
Alen BreatheSmart 45i HEPA Air Purifier
Alen BreatheSmart 75i
Alen BreatheSmart FIT50
Alen BreatheSmart Classic

Comparison Articles
Alen vs. RabbitAir vs. Molekule


As you can clearly see, the Alen BreatheSmart FLEX is not the most feature-rich air purifier out there, nor is it the strongest in terms of cleaning range. Furthermore, the fact that you need to swap out HEPA filters to either eliminate odors or snatch most pesky particles from the air can be a put-off for some.

However, what it does, it does extremely well, and its high CADR ratings are evidence of this fact. Plus, if aesthetics is a priority in your shopping for a good air purifier, you’ll be glad to know that the FLEX is all about style.

Alen FLEXw

Recommended Affordable Air Purifiers
Best of the Best! Budget Pick Also Great
Coway Airmega 300 Smart Air Purifier with 1,256 sq. ft. Coverage Germ Guardian True HEPA Filter Air Purifier for Home, Office, Bedrooms, Filters Allergies, Pollen, Smoke, Dust, Pet Dander, UV-C Sanitizer Eliminates Germs, Mold, Odors, Quiet 22 inch 3-in-1 AC4825 Coway AP-1512HH Mighty Air Purifier with True HEPA and Eco Mode in White
Coway Airmega 300 Germ Guardian AC4825 Coway AP-1512HH
1,256 sq. ft. Coverage
True HEPA filter
167 sq. ft. Coverage
True HEPA filter
361 sq. ft. Coverage
True HEPA filter
300 Dust | 340 Pollen | 310 Smoke
118 Dust | 125 Pollen | 108 Smoke
246 Dust | 240 Pollen | 233 Smoke

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