Alen BreatheSmart Flex HEPA air purifier review – Is it medically approved?


FLEX air purifiers were designed for use in medium-sized rooms, such as bedrooms, offices or kitchens. Their 4 interchangeable HEPA air filters are easy to change and each filter addresses specific needs, allowing you to tailor your air purification to your liking. Experience powerful performance and effective air purification with the Alen BreatheSmart FLEX. Breathesmart FLEX by Alen, as we’ll see in this review, is a bedroom-friendly medium-sized air purifier. It has up to 700 sq ft coverage area, exceedingly high 225 CADR rating, and super H13 medical-grade HEPA filtration system. Is it medically approved? Find details in Alen BreatheSmart Flex HEPA air purifier review.

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In The Box

  • BreatheSmart FLEX air purifier
  • True HEPA Pure filter
  • Designer panel (optional)
  • Quick start guide

What is good in H13 True HEPA filter?

H13-True HEPA Medical Grade Filter Options:

1. Pure Filter = Dust, Mold, Pet Odors removes dust, dander, pollen, fur

2. Fresh Filter = Dust, Mold, Pet Odors PLUS Light Smoke removes dust, dander, pollen, fur and absorbs light smoke with 0.66 lbs of activated carbon

3. Smoke Filter = Dust, Mold, Pet Odors PLUS Heavy Smoke removes dust, dander, pollen, fur and absorbs heavy smoke with 2+ lbs of activated carbon

*H13 True HEPA removes 99.99% bacteria, aerosolized viruses, and airborne particles larger than 0.1 micron

Pros & Cons – Alen BreatheSmart Flex HEPA air purifier


  • Can cover 280-700 sq ft bedrooms with energy-saving max. 45 wattage
  • Advanced H13 HEPA filters can achieve a 225 CADR rating at 187 max. airflow (remarkable above 1:1 ratio)
  • Low maintenance costs due to Energy Star rating and improved lifespan of H13 HEPA filters (12 months)
  • Most affordable Alen BreatheSmart air purifier with an appealing look


  • It’s quiet but not as quiet as the newer yet more expensive 45i model (49 dB vs 55 dB max. noise levels)
  • Doesn’t have the most up-to-date wifi capability and smartphone connectivity features

Specification – Alen BreatheSmart Flex HEPA air purifier

  • CFMSpeed 1: 53 CFM | Speed 2: 135 CFM | Speed 3: 147 CFM | Turbo: 187 CFM
  • CADR225
  • Cord Length7ft 8inches (233cm)
  • CoverageUp to 700 SqFt (65.03 m2) | Cleans all air in room every 30 minutes @ highest setting
  • DimensionsH 25″ (63.50 cm) x W 15″ (38.10 cm) x D 8.5″ (21.59 cm)
  • Energy StarYes
  • Filter Cost$69 | Using “Pure” Filter
  • Filter Life12 months | @ Recommended 24hr/day operation
  • Filtration RateRemoves 99.99% of particles greater than 0.1 microns
  • Noise LevelLowest Speed 39 dBa | Highest Speed 55 dBa
  • Ozone0 PPM
  • Power Consumption.8 to 56 watts
  • Power Supply120 AV, 60HZ (2 Prong Power Cord)
  • SensorNA
  • Sound TypePink Noise | All speeds
  • Speed Settings4
  • WarrantyLifetime | with Product Registration & Active Filter Subscription
  • Weight15 lbs (6.8 kg)

Key feature – Alen BreatheSmart Flex HEPA air purifier

Four interchangeable True HEPA filters allow you to customize your specific filtration needs. The True HEPA-Pure filter comes standard with the FLEX, all other filters are optional and are sold separately:

  • True HEPA-Pure (FL40) filter: two-layer filter. Removes dust, pet dander, mold and pollen from the air.
  • True HEPA-Fresh (FL40-carbon): three-layer filter. Removes dust, light smoke, mold and pollen from the air, and provides light odor control.
  • True HEPA-Silver (FL40-Silver-Carbon): three-layer filter. Purifies and freshens the air and protects against the growth of bacteria and microbes. It also captures VOCs and removes dust, pet dander, mold and pollen from the air.
  • True HEPA-OdorCell (FL40-MP): three-layer filter purifiers the air and destroys heavy odors. Removes dust, pet dander, mold and pollen from the air.

Washable pre-filter layer extends the life of the filtersFiltration rate: removes 99% of particles larger than 0.3 microns in sizeCleans rooms up to 700 sq. ft. (2 air changes per hour)Simple-to-use, intuitive touch-button controls that operate with a quick, light touchDelivered airflow: Speed 1: 53 CFM, Speed 2: 135 CFM, Speed 3: 147 CFM and Turbo: 187 CFM4 fan speed controls: speeds 1-3 and turbo; lights display the selected speedNoise levels:

  • Speed 1: 39 dB (whisper)
  • Speed 2: 42 dB (light rainfall)
  • Speed 3: 49 dB (heavy rainfall)
  • Turbo: 55 dB (box fan, medium)

Filter-life indicator:

  • Green: illuminates for most of the filter’s life—doesn’t need replacing
  • Yellow: illuminates to indicate that the filter should be replaced soon
  • Red: illuminates when it is time to replace the filter (6-9 month lifespan)
  • Timer settings: 2-, 4- or 12-hour timer to control air circulation
  • Power/sleep mode: Auto-off feature when the front cover is removed
  • Handle for easy carrying and maneuvering
  • Weight: 15 lbs.
  • Quick-start guide and owner’s manual included
  • Manufacturer’s lifetime warranty

Alen BreatheSmart FLEX Price

Buying an Alen BreatheSmart FLEX is a smart investment in more than one way. The most obvious one is the price of the unit itself. Alen BreatheSmart FLEX costs $349. Check if there are any available FLEX sales at this time.

For comparison, the bigger Alen BreatheSmart units usually cost more than $500. The newer Alen air purifier, with comparable specs, is the BreatheSmart 45i costs $429.

Even more important than the unit cost are maintenance costs. Usually, you have to replace HEPA and activated carbon filters every 3-6 months and 6-9 months, respectively. The H13 HEPA filters by Alen need to be replaced every 12 months, or so. 

Who is this for

Alen BreatheSmart Flex is Best For:
  • If you value style– this model offers 14 customizable panels with modern wood trim designs to adorn your décor.
  • Those with allergies and asthma– the Flex uses a HEPA (High-Efficiency Particulate Air) filter that has been proven to remove most household air pollutants that may worsen respiratory problems. These include dust, pet dander, dust mites, and mold spores.
  • Pet owners with fur shedding issues– this purifier also traps dog and cat fur in the air.
  • Those with large sitting rooms or bedrooms– this air purifier offers a coverage of up to 700 sq.ft.w34


Whats is more, the H13 HEPA filters in the Alen BreatheSmart FLEX last 3-5 months longer, reducing the maintenance cost of HEPA. Even if you run FLEX 24/7, you will only have to buy Alen BreatheSmart FLEX replacement filters every 12 months or so.

Alen BreatheSmart FLEX has the coveted Energy Star certificate for being in the top 10% of the most energy-efficient air purifiers. If you run it on max. for a whole day, it will spend about 1 kWh. In dollar terms, that’s less than $0.20 per day and about $1 per week.

Compare BreatheSmart Flex vs BreatheSmart Fit50

BreatheSmart FlexBreatheSmart Fit50BreatheSmart Classic
Coverage Area -By Square Feet700 Square Feet900 Square Feet1,100 Square Feet
Compatible Filters – By Targeted Concerns244
Ionizer FeatureNo
Designer Color Panel Options
Smart Sensor & Air Quality IndicatorNo
Power Consumption36 Watts60 Watts105 Watts
Filter Life (Running 24/7)9-12 Months9-12 Months9-12 Months
Air Purifier for Your SpaceBathrooms, Bedrooms, Dens, Family Rooms, Kitchens, Dining Rooms, Nursery Rooms, Offices, Basements, Small ClassroomsBedrooms, Master Bedrooms, Family Rooms, Game Rooms, Kitchens, Living Rooms, Basements, Offices, Play Rooms, ClassroomsBedrooms, Open Concept Floorplans, Big Bedrooms, Game Rooms, In-Law Suites, Living Rooms, Open Office Spaces, Finished Garages, Basements, Workshops, Classrooms

Alen BreatheSmart Flex HEPA air purifier review


The Alen Flex is a full-size air purifier mainly made of metal. We’ve come across air purification units with very high price tags despite their flimsy plastic construction. So, this model’s metallic build is an excellent value, especially at its mid-range price tag.


Despite of being a full-size air purifier, the Alen BreatheSmart FLEX has a height of 25 inches, which is even taller than the current Alen Paralda. That means a bigger size air filter will be applied to capture more allergens for you. Moreover, the air flow system concept has changed, to a common bottom-to-top. With a big air intake grill behind the panel, the Alen BreatheSmart FLEX draws in polluted air, purifies it and releases back through the top air vent. A typical air flow concept which are used widely in price range of $300 to $400, from Blueair Classic 205 to Rabbit Air BioGS 2.0 and GermGuardian AC9200WCA.


Bigger in size, the Alen BreatheSmart FLEX is only 15 lbs. With a necessary handle on top of this air purifier, you can easily grab it and move it anywhere in your home.

Touch panel

The control interface is a touch-sensitive 4.5-inch wide panel at the top. What we like about it is that the 5 buttons have been nicely spaced and labeled for easy use.

Smart sensor

This model also has a Laser Smart Sensor that detects the air quality in the room. The results are displayed in 3 different colors by a LED Air Quality Indicator around the power button. Unfortunately, the Flex does not have an Auto Mode. So, you’ll need to make the appropriate adjustments in speed fan manually.

Alen BreatheSmart FLEX


The interesting part is this: Alen BreatheSmart FLEX actually has an H13 medical-grade filter. This FLEX H13 is so thorough they use it in hospitals, clinics, dental clinics, and so on (hence the ‘medical-grade). It’s designed to capture more than 99.99% of 0.1-micron particles. These particles are 3 times smaller than what standard H10-H12 HEPA filters can handle.

Pure, Fresh, OdorCell, Heavy Smoke Filters

Pure filters are quite amazing. What is more, Alen offers 3 advanced filtration systems that build on the Pure filters. It’s basically Pure filters + specific addition. Here are all 3 advanced Alen BreatheSmart FLEX filtration systems:

Alen BreatheSmart FLEX uses it’s ‘Pure’ filtration system as the basic filter. It a combination of the H13 HEPA filter and antimicrobial filtration. Alen BreatheSmart FLEX with Pure filter will remove allergens, dust, mold, germs, and bacteria from indoor air.

  • Fresh or Light Smoke. It will take care of odors like cooking oil smell, cigarette smell, and VOCs. The addition: 0.66 lbs activated carbon filter.
  • Heavy Smoke. Basically Fresh filter with a big 2+ lbs activated carbon filter. It’s the ultimate smoke filtration killer.
  • OdorCell. Another activated carbon filter addition, designed at removing household odors like diaper smell.

Room coverage

It needs to be said that if you put Alen FLEX in a 700 sq ft room, it will completely change the air in that room every 30 minutes. Essentially, it will perform 2 air changes per hour or 2 ACH.Essentially, the FLEX’s coverage area is between 280 sq ft (intense air purification) and 700 sq ft (standard air purification). It’s better to put it in a 280-400 sq ft room in order to truly increase the indoor air quality significantly.

Despite weighing only 15 lbs, BreatheSmart FLEX is capable to handle medium-sized and large rooms up to 700 sq ft. That’s thanks to the 225 CADR rating, of course.


Alen BreatheSmart FLEX has an above-average 225 CADR rating. That means it can capture the minuscule air pollutant better than an average air purifier, and with greater efficiency. 

The brilliant engineering that went into the FLEX is obvious when you compare the CADR rating to FLEX’s max. airflow. Alen BreatheSmart FLEX has a maximal airflow of 187 CFM. Spec-by-spec that’s lower than CADR rating. This is one of the few air purifiers that can deliver a 225 CADR rating at below 200 CFM max. airflow. That’s really brilliant engineering; you will hardly find such CADR to airflow ratio even in the large room $800+ air purifiers.

225 CADR is an average of 3 Alen BreatheSmart FLEX CADR ratings:

  • Pollen CADR = 230.
  • Dust CADR = 208.
  • Smoke CADR = 191.

The high CADR rating enables Alen BreatheSmart FLEX to cover larger spaces:


Alen BreatheSmart FLEX noise levels are between 39 dB for the low-speed setting to 55 dB for the high-speed setting. That’s quite low for a 700 sq ft coverage area air purifier.

However, it needs to be said that, if you compare the FLEX to other Alen BreatheSmart air purifiers like 45i and 75i, the 55 dB maximal noise level is quite high.

To get a grip of how quiet Alen BreatheSmart FLEX is, however, you need to compare it to other air purifiers like Blueair, Coway, Levoit, Medify, Winix, Honeywell, Dyson, and so on.

Alen BreatheSmart Flex HEPA air purifier – Special Features

FLEX has several of the features characters for Alen BreatheSmart air purifiers. This includes the technologies aimed at improving the quality of sleep, which include:

  • WhisperMax. The very technology that makes the Alen BreatheSmart the quietest air purifiers on the market.
  • Light Out Mode. Dims or completely shuts off all the lights on the air purifier.
  • Sleep Mode SleepScore validation; a study that found people who used Alen BreatheSmart FLEX better rested upon waking.

On top of that, you get all the basic features such as Set Timer for 2, 4, or 12 hours and filter indication that tells you when to replace H13 HEPA filters.

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.

How to operate Alen BreatheSmart Flex HEPA air purifier?

  1. Plug your air purifier into a grounded outlet.
  2. Press Power Button in the center to start the air purifier. When your unit is on, the lights will light up. To turn off the lights on your unit, press the Power Button. To turn off the air purifier, press the Power Button again after the lights have turned off.
  3. FILTER Indicator — The Filter indicator has 3 lights: Green, Yellow and Red. The Green light will be illuminated for most of the life of the filter. The Yellow light will come on shortly before your filter should be replaced. This is the ideal time to order a new filter. The Red light will be illuminated when it is time to replace the filter.
  4. After changing the filter, hold the FILTER button down for 5 seconds. The Red light will be reset to Green.
  5. Press TIMER to have the air purifier run for a set amount of hours (either 2, 4 or 12) before turning off.
  6. Press SPEED and watch the indicator lights until desired fan speed is achieved. Most users prefer to use the air purifier on speed 2 or 3 to balance cleaning speed and noise.
    If you suspect the air is particularly dirty, you should set the speed to T (Turbo).
  7. Press and Hold LOCK for 3 seconds to Lock/Unlock the Control Panel.

Alen BreatheSmart Flex HEPA air purifier customer review

Excellent Product

I’ve been using the Alen BreatheSmart Flex for about 2 years now and just purchased a second one. It’s got a wide range of speeds and the lowest speed is so quiet, you hardly know it’s on. The controls are super easy to understand. It’s not an inexpensive item though (otherwise you’d get 5 stars), but if you can afford it, it’s worth the improvemeRead more about review stating Excellent Productnt for someone like me with allergies.

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