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Alen BreatheSmart FLEX True HEPA Air Purifier

Alen BreatheSmart FLEX True HEPA Air Purifier is an air purifier intended for larger rooms and areas, featuring excellent air filtration, a very simple control panel, low noise operation, long air filter replacement period, etc.

As its label suggests, Alen BreatheSmart FLEX True HEPA Air Purifier is very "flexible" regarding its use, the choice of air filters, but also its color.

With four (4) different air filters, Alen BreatheSmart FLEX True HEPA Air Purifier can be customized for almost any type of airborne pollutants.

Published: June 11, 2022.

alen flex hepa air purifier 1

Alen BreatheSmart FLEX True HEPA Air Purifier Features and Specifications

Alen BreatheSmart FLEX True HEPA Air Purifier is a stylish-looking unit that in combination with 5+ different colors/styles can easily fit any room.

Alen FLEX air purifier features physical dimensions of (H x W x D) 25 x 15 x 8.5 inches (~63.50 x 38.10 x 21.59 cm) and weighs ~15 pounds (~6.8 kg).

The unit is designed for areas up to 700 sq. ft. (~65 m2), but if required, it can cover even larger areas.

Note: when set to the highest speed setting, the Alen FLEX air purifier can purify all air in a 700 sq. ft. room in ~30 minutes.

Also, the Alen FLEX air purifier is designed for 24/7 operation - personally, set it to a permanent location, set it to speed 1 or perhaps speed 2 and enjoy the much cleaner air...

oak color

Air intakes are on the sides and front bottom, while purified air exhaust is at the back top - it is recommended to place the unit with some space (1-2 feet) free on its sides and in front of the unit.

Note: air exhaust has a tendency to mix layers of air, equalizing the air temperature in the room, and further improving the air quality.

With a power cord length of 6 feet and 4 inches (~193 cm), users should easily find "the best" position for the unit.


Controls of the unit are at the top and they include:

- Filter indicator and reset button,

- Timer indicator and control button, allowing the user to set time to 2, 4, and 12h,

- Start and Stop Button,

- Speed indicator and control button with 4-speed settings,

- Lock button.

Alen FLEX air purifier power consumption ranges from 0.8 watts (Standby) to 56 Watts (Maximum Speed), while noise levels range from 25 dB (Lowest Speed) to 50 dB (Maximum Speed).

Airflow also depends on the airspeed:

- Speed 1: 53 CFM (Cubic Feet per Minute),

- Speed 2: 135 CFM,

- Speed 3: 147 CFM,

- Speed 4: 187 CFM.

Alen FLEX air purifier features a CADR (Clean Air Delivery Rate) value of 225.

Alen FLEX Air Purifier Air Filtration System

Alen FLEX air purifier comes with a very simple, but also very efficient air purification system, consisting of a mechanical air prefilter and a true HEPA air filter.

As said before, a true HEPA air filter is offered in several versions:

- Alen BreatheSmart FLEX True HEPA-Pure Filter: B4-Pure / FL40-Pure, intended for dust, mold, pet odors,

- Alen BreatheSmart FLEX True HEPA Fresh Filter: B4-Fresh / FL40-Silver-Carbon, intended for dust, mold, pet odors, and smoke

- Alen BreatheSmart FLEX True HEPA-OdorCell Filter: B4-Odor / FL40-MP, intended for dust, mold, pet odors, VOCs and smoke,

- Alen BreatheSmart FLEX True HEPA-Smoke Filter: FL40-H, intended for dust, mold, pet odors, VOCs, and heavy smoke.

alen fl40 h air filter

Of course, as the ability of the air filter to capture airborne dust, allergens, Volatile Organic Compounds (VOCs), tobacco smoke, pollution, pet odors, household smells, etc. increases, so does its price.

However, the main filter should be replaced every 9-12 months, depending on the air purifier use and local air pollution, so personally, go for the best and most capable model (FL40-H model) and don't look any further.

For example, Alen FL40-H true HEPA air filter also contains 2 pounds (~900g) of activated carbon, enabling it to thoroughly purifier air that passes through it - according to the manufacturer, it stops 99.99% of 0.1 microns or larger particles.

To protect the main HEPA air filter, the Alen FLEX air purifier also features an air prefilter, which should be regularly vacuumed to remove the build-up of dust, hair, dander, and other dirt that air purifiers quickly collect.


Air prefilter is replaced when the main true HEPA air filter is replaced, but for users who want to replace it more often, Alen also offers air prefilter packages containing four air prefilters.

Since its air filtration system doesn't use UV light or ion generator of some kind, Alen FLEX air purifier doesn't produce ozone, not even in traces.

Alen FLEX air purifier comes with two types of warranty:

- standard 1-year limited warranty,

- lifetime warranty on the device, which must be registered and must include an active air filter subscription.

This second option is highly recommended - personally, of course.

Note: Alen BreatheSmart FLEX True HEPA Air Purifier is a very simple to use and maintain true HEPA air purifier, but when it arrives, be sure to read the Owner's Guide/manual in order to get customized to your new air purifier.

alen flex hepa air purifier mLong Story Short:  If You are looking for a true HEPA air purifier that doesn't come with advanced features like WiFi, Bluetooth, voice prompt, smartphone App support, and similar, consider this model - it is designed to operate practically non-stop, it is easy to set (and forget), it features very low noise levels, it is energy very efficient, etc.

Although the user can choose between 4 (four) different air filters, the Alen FL40-H model is highly recommended - it is the most expensive air filter offered for this air purifier, but it also offers the best air purifying performances.

For more reviews and recommendations, feel free to check the Alen BreatheSmart FLEX True HEPA Air Purifier and the Alen FL40-H True HEPA Air Filter Amazon links (links open in the new windows).

Amazon Search:

- HEPA Air Purifier

Note: Amazon link opens in the new window, feel free to check it for the most up-to-date offers and prices.

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