5 Best-Of-The-Best Alen BreatheSmart Air Purifiers (2024 Review)

Alen BreatheSmart is probably the best line of air purifiers ever created.

Alen BreatheSmart air purifiers are all the rage. It’s not all about the exquisite design either; Alen has always been known as a top-notch best-of-the-best air purifier brand.

Here are just a few things that make Alen air purifiers so great:

  1. Powerful yet very quiet operation. You won’t see a 300+ CADR rating air purifier with below 50 dB max. noise levels anywhere else; only Alen creates these big quiet air purifiers for bedrooms.
  2. Use of superior H13 medical-grade HEPA filters. They remove 99.99% of air pollutants like dust, smoke, pollen, etc. down to 0.1-microns; standard HEPA removes 99.97% of air pollutants down to 0.3-microns.
  3. The premium price of Alen units is balanced out by the 12-month filter lifespan; high costs in short term, low costs in long term. Standard HEPA filters have to be changed every 4-6 months.
  4. Smart Sensor technology measures the quality of air in real-time. How do you know what your air quality is and how well Alen BreatheSmart air purifiers are performing? Each Alen BreatheSmart unit has a neat built-in air quality sensor that adjusts the performance of the air purifier to maximize the air quality.
  5. 1st and only lifetime warranty. Alen engineering is superb; so much so that they feel confident that nothing will go wrong with their units. If it does, they will help you out, you have a lifetime warranty, they’ll even ship you replacement parts for free if needed.

That was true even before the BreatheSmart series.

Here’s the kicker:

In 2018, Alen introduced the BreatheSmart Classic, FLEX, and FIT50. Everybody in the air purifier industry was excited.


Alen BreatheSmart weren’t just new Alen air purifiers. They were specifically designed to improve the quality of sleep.

Alen partnered with SleepScore Labs, the Sleep Science Company that evaluates the effect of various devices on sleeping patterns. To assess the Alen BreatheSmart air purifiers, they had a trial with 40 individuals with poor sleep quality.

Here’s how the sleeping study was conducted:

SleepScore Labs tracked 40 individuals. They managed to get the data from 1,591 nights.

In their bedrooms was 1 of these 4 BreatheSmart air purifiers:

  • BreatheSmart FLEX.
  • BreatheSmart FIT50.
  • BreatheSmart 45i (new series).
  • BreatheSmart 75i (new series best-seller).

Here what the study found out:

“Participants reported falling asleep faster and felt more rested the next day when using Alen purifiers at night.” (SleepScore Labs study findings)

In essence, Alen BreatheSmart is not just another line of HEPA filter-based air purifiers that removes odors, smoke, mold, dust, and so on. It more than that; according to the SleepScore Labs study, it:

  • Makes you fall asleep faster.
  • Makes you wake up more rested.

If you already have a good mattress, the next best thing to improve sleep (and air) quality is an Alen BreatheSmart air purifier.

But which BreatheSmart to choose?

There are 5 of them: FLEX, FIT50, 45i, and 75i. Here’s a bit of a hint:

45i as the best alen breathesmart air purifier
Front of Alen BreatheSmart 75i air purifier. The 75i is arguably the best overall BreatheSmart model (quietest, most versatile, highly capable). You will find it under the #1 review further on.

In our reviews, we usually try to figure out if a certain air purifier is good (or not). Alen air purifiers are a different case altogether because of 1 thing:

We already know that the Alen BreatheSmart air purifiers are fantastic (specs-wise, value, worth it, and so on).

In this Alen BreatheSmart review, we’ll help you figure out which of the 5 BreatheSmart air purifiers is best for your home.

Note: If you have several bedrooms – like a master bedroom, kids room, and so on – you can buy several different BreatheSmart air purifiers.

List Of 5 Best Alen BreatheSmart Air Purifiers

All BreatheSmart units are designed for use in the bedroom. The 3 ideas that bedroom-friendly BreatheSmart air purifiers are based upon are these:

  1. Should be powerful enough to filter out all the air pollutants that may decrease sleep quality.
  2. Should be quiet enough (3/5 BreatheSmart purifiers have below 50 dB max. noise levels).
  3. Shouldn’t have all those light elements air purifiers usually have.

With that in mind, here is the overview of all 5 Alen BreatheSmart devices. The air purifiers are ranked from the best – the 75i is the most perfect air purifier ever designed – to the worst. Below the comparison table, you will find individual BreatheSmart reviews as well:

  1. Alen BreatheSmart 75i: Quietest and best Alen BreatheSmart model; #1 ranked air purifier overall.
  2. Alen BreatheSmart Classic: Best Alen air purifier for large rooms.
  3. Alen BreatheSmart 45i: Best for standard-sized rooms.
  4. Alen BreatheSmart FLEX: Best for smaller rooms.
  5. Alen BreatheSmart FIT50: Very compact Alen BreatheSmart air purifier.

(scroll right, and down)

Alen Air Purifier: BreatheSmart 75i BreatheSmart Classic BreatheSmart 45i BreatheSmart FLEX BreatheSmart FIT50
Max. Coverage Area: 1,300 square feet 1,100 square feet 800 square feet 700 square feet 900 square feet
CADR Rating: 350 300 245 225 220
Max. Airflow: 347 CFM 290 CFM 215 CFM 187 CFM 231 CFM
Power Output: 1.8 – 45 Watts 1.6 – 105 Watts 1.1 – 50 Watts 0.8 – 45 Watts 1.2 – 60 Watts
Filters: 75i True HEPA (H13) True HEPA Pure (H13) 45i True HEPA (H13) True HEPA Pure (H13) True HEPA Pure (H13)
Filter Lifespan:

Filter Price:

12 Months


12 Months


12 Months


12 Months


12 Months


Noise Levels: 25-49 dB 42-56 dB 23-49 dB 39-55 dB 32-49 dB
Air Purifier Price: $$$$ $$$$$ $$$$ $$$$ $$$$
Average Rating: 5 out of 5 stars 4.8 out of 5 stars 4.7 out of 5 stars 4.5 out of 5 stars 4.5 out of 5 stars
Availability: Check Price Check Price Check Price Check Price Check Price

5 Best Alen Air Purifiers Reviews

To properly review all Alen BreatheSmart air purifiers, we need to look at all 5 specification sheets.

We’ll compare and contrast FLEX, FIT50, Classic, 45i, and 75i first (specs-wise). Further on, you will find individual reviews with the answers to:

  • Which Alen BreatheSmart is the best for the kid’s room?
  • Which one is best for several rooms?
  • Which BreatheSmart air purifier is best for a master bedroom?

The primary factor for these decisions is the maximal coverage area:

Max. Coverage Area (From 700 Sq Ft To 1300 Sq Ft)

The first BreatheSmart series was FLEX, FIT50, And Classic. The maximum coverage area of these Alen purifiers is 700 sq ft, 900 sq ft, and 1100 sq ft, respectively.

Here’s the translation (based on BreatheSmart coverage area):

  • FLEX is for smaller rooms, such as the kid’s room.
  • FIT50 is for medium-sized rooms, such as a normal bedroom.
  • Classic is the larger rooms, such as the master bedroom.

That was the standard BreatheSmart line-up. The new 45i and 75i air purifiers have a maximum coverage area of 800 square feet and 1,300 square feet.

Coverage-wise this translates into:

  • 45i is a more powerful BreatheSmart FLEX for the kid’s room.
  • 75i is a more powerful BreatheSmart Classic for the master bedroom.

The 45i and 75i differ from the original series because they have an upgraded HEPA filter. The better filter has a significant effect on the Alen BreatheSmart unit’s CADR rating:

CADR Rating (From 220 To 350)

The CADR rating is probably the single most important air purifier specification. You will find other specs such as coverage area, airflow, wattage, noise levels in air conditioner, dehumidifier, even furnace specification sheets.

The CADR rating was specifically devised for air purifiers.

It stands for Clean Air Delivery Rate; basically, the amount of clean air an air purifier can deliver. The more, the better, right?

All Alen air purifiers have exceptionally high CADR ratings. The BreatheSmart FLEX, FIT50, and Classic have 225, 220, and 300 CADR rating, respectively.

A higher CADR rating also means that you can put such an air purifier – like BreatheSmart Classic with a 300 CADR rating – in bigger rooms.

Max. Airflow (187 CFM To 347 CFM)

Maximal airflow is an air purifier specification that is secondary to CADR rating. In all our reviews – including this Alen SmartBreathe review – we stress the following:

You don’t need to be stressed with the maximum airflow. Just make sure that the CADR rating is above 150.

150 CADR rating is a safe bet that an air purifier is actually a good purifier, not a mere air blower. The filter has to actually pick all those dust, smoke, mold, dander, and other particulates out of the air and deliver clean air back into the room.

Here is how big an airflow BreatheSmart FLEX, FIT50, Classic, 45i, and 75i create, respectively: 187 CFM, 231 CFM, 290 CFM, 215 CFM, 347 CFM.

Power Output (From 0.8W To 105W)

Alen BreatheSmart purifiers have 3 or 4 fan settings. That also means they have 3 or 4 different energy inputs and outputs.

In general, air purifiers – including 4 Alen BreatheSmart units – are fairly inexpensive (electricity-wise).

For example, FLEX, FIT50, and the new 45i and 75i need 60 Watts to else, even at the maximum fan speed setting.

Which unit is the exception?

The BreatheSmart Classic. Running at full speed, it will drain 105 Watts. Eco-wise, this is not ideal. Due to higher energy usage, you can also see a higher maximum noise level (56 dB).

Apart from the Classic, all other 4 BreatheSmart units we review are eco-friendly from the electricity needs viewpoint.

Type Of Filters, Lifespan, Price (12 Months, Up To $100)

Filters are the heart of all Alen air purifiers. For the BreatheSmart series, only the best True H13 HEPA filters are used. Here’s what you need to know about HEPA filters:

True H13 HEPA filters remove 99.99% harmful particles down to 0.1 microns—including allergens, dust, mold, bacteria, aerosolized viruses, and additional air pollutants.

These BreatheSmart HEPA filters are designed to last up to 12 months. Replacement filters cost anywhere from $50 for smaller FLEX to $150 for the biggest 75i model.

It gets better:

Each BreatheSmart unit has two or more filter choices:

  • HEPA H13 filter is Option 1.
  • HEPA H13 filter with a special filtration flavor is Option 2, 3, 4, and so on.

Those ‘special filtration flavor’ can mean filtration specialized for odors, allergies, dust, mold, and so on. That’s on top of the existing H13 filter.

We’re going to look into all filter options for a specific unit in the individual BreatheSmart reviews further on.

Noise Levels (From 23 dB To 56 dB)

Air purifiers are turned on 24h per day. That means they will be running less than 20 feet from us when we’re sleeping.

It was essential for Alen to keep the BreatheSmart unit’s decibel levels as low as possible.

Here’s the result:

On average, BreatheSmart air purifiers are one of the quietest air purifiers on the market.

3 of them – FIT50, 45i, and 75i – don’t go over 50 dB even on the turbo setting.

BreatheSmart 45i, the standard room new BreatheSmart air purifier, is the quietest BreatheSmart unit. At a low setting, it purrs at 23 dB.

For comparison: An indoor cat’s purr is at 25 dB noise levels. 45i is quieter than that.

Being so quiet makes them perfect for bedroom air purification.

Alen BreatheSmart Prices (From $300 To $800)

Everybody knows that the best products in the market are never cheap. iPhone is not the cheapest version, Yankee candles are not the cheapest, and the same is true for Alen BreatheSmart air purifiers.

The prices for the small units start at around $300-$400 and can reach almost $1,000 for the biggest 75i. If you consider that people usually buy 2-3 BreatheSmart air purifiers in one purchase, it can get quite expensive.

Nonetheless, quality air purifiers are never cheap. Alen is one of the best brands, and their BreatheSmart series is their best line. With sleep science data-based research, and the best HEPA filtration systems employed, one thing is pretty clear:

Despite being a bit pricy, Alen BreatheSmart air purifiers are well worth the money.

With that in mind, let’s finally look at reviews of all 5 BreatheSmart air purifiers:

1. Alen BreatheSmart 75i Review (Best Overall Air Purifier In 2024)

the biggest and best alen breathesmart air purifier
Max. Coverage Area: 1300 sq ft
CADR Rating: 350
Max. Airflow: 347 CFM
Filters: 75i HEPA Pure
Filter Lifespan: 12 Months
Power Output: 0.8 – 45 Watts
Noise Levels: 25-49 dB
Dimensions: 27″ x 18.5″ x 11.5″
(H x W x D)
Weight: 27 lbs
Price: $$$$
Average Rating: 5 out of 5 stars

Words hardly describe how well-balanced Alen BreatheSmart 75i. This is the perfectly engineered air purifier everybody is talking about. It is rated as the #1 air purifier in 2024 overall, based on the analysis of 529 AHAM-certified air conditioners.

The 75i model is an upgrade of the very popular Classic model from the 1st BreatheSmart series.

It’s quite incredible that a low-wattage Energy Star certified air purifier can produce such an air purification CADR rating. It’s the ultimate eco-friendly air purifier.

On top of that, it’s the quietest air purifier ever design. At a low fan speed setting, it produces merely 25 dB.

The 75i model solves both issues many air purifiers struggle with the most:

  • It’s extremely energy-efficient. An eco-friendly 45W max engine powers it.
  • The 75i is the quietest large room air conditioner with up to only 49 dB noise levels.

Now, both of these specs are brilliant.

But it gets even better:

75i outmatches all BreatheSmart model in capacity. Get this: it has a CADR rating of 350. All other units have a CADR rating of 200ish, or 300 (Classic model). With such a high CADR rating, 75i is more than capable of covering 1,300 sq ft; that’s almost unheard of. As such, the 75i model is considered to be the best air purifier for large 1000+ sq ft rooms, as seen here.

All in all, 75i BreatheSmart is an engineering masterpiece. Add the brilliant True HEPA filters, which are the basis of the BreatheSmart air purifiers, and you have yourself the best large room air purifier.

Alen BreatheSmart 75i

  • Most energy-efficient air purifier
  • Quietest air purifier with 25-49 noise level internal; perfect for bedrooms
  • True air purification powerhouse; with a 350 CADR rating
  • It can cover 1,300 sq ft – that means you can use it to purify the air in more than 1 room
  • Incredibly energy-efficient and quiet operation
  • It’s definitely pricy because you can buy 1 unit to cover several rooms

2. Alen BreatheSmart Classic Review (Best Large Room Air Purifier For Master Bedrooms)

best alen large room air purifier
Max. Coverage Area: 1100 sq ft
CADR Rating: 300
Max. Airflow: 290 CFM
Filters: True HEPA Pure
Filter Lifespan: 12 Months
Power Output: 1.6 – 105 Watts
Noise Levels: 42-56 dB
Dimensions: 26.75″ x 17.75″ x 10″
(H x W x D)
Weight: 21 lbs
Price: $$$$
Average Rating: 4.8 out of 5 stars

Alen Classic large room air purifier is a true BreatheSmart powerhouse. With 105W, it can create 290 CFM airflow. It has an outstanding 3000 CADR rating. This air purifier can purify the air very well in up to a 1,100 sq ft area.

Because the Alen BreatheSmart Classic is thus perfect for large bedrooms. If you have a master bedroom (good job, by the way), the Classic unit is the perfect one for you; or at least that would be said in 2019.

In 2019, Alen introduced the 75i. 75i is an upgrade of the Classic model; there were some problems with this large room air purifier.

The fact that it can be powered by 105W is not very eco-friendly. Nor are the maximum 56 dB noise levels ideal. And it weighs 20+ lbs.

All in all, large rooms and CADR ratings do go well together. However, for a true master bedroom, the new 75i (#5 review) would be the best.

Alen BreatheSmart Classic

  • Superb H13 medical-grade HEPA filters
  • Highest CADR rating of the 1st line BreatheSmart air purifiers
  • Perfect for larger rooms, such as a master bedroom or living rooms
  • Lower price compared to its new brother 75i
  • It is powered by 105W; not the best for electricity bill and the environment
  • At turbo level, it produces 56 dB of noise
  • Is surpassed by the BreatheSmart 75i model

3. Alen BreatheSmart 45i Review (Best For Standard-Sized Rooms)

best alen breathesmart air purifier for allergies
Max. Coverage Area: 800 sq ft
CADR Rating: 245
Max. Airflow: 215 CFM
Filters: 45i True HEPA
Filter Lifespan: 12 Months
Power Output: 1.1 – 50 Watts
Noise Levels: 23-49 dB
Dimensions: 25″ x 15″ x 8.5″
(H x W x D)
Weight: 15 lbs
Price: $$$$
Average Rating: 4.7 out of 5 stars

If one unit should be called ‘The Best Alen BreatheSmart Air Purifier for everyone’, it would definitely be the new SmarteBreathe 45i model. The 45i model is also considered to be the best overall air purifier for bedrooms.

In one swoop, Alen has upgraded both the FLEX and FIT 50 by creating the 45i model. They took the strong points (quiet operation, high CADR, low power expenditure) and used them all when creating the 45i model.

Here are some examples:

  • 45i has a very high CADR rating of 245 (FLEX has 225, FIT50 has 220).
  • 45i is the quietest BreatheSmart unit (even quieter than FIT50).
  • It conserves energy well and is eco-friendly, with only 60W max. power.

All in all, it’s not hard to see that everybody wants Alen BreatheSmart 45i in 2024. It is the upgraded line, insanely quiet, can fit pretty much any space below 800 sq ft, and you can easily buy several of them.

It is also one of the highest-rated air purifiers in general:

Alen BreatheSmart 45i

  • Best overall Alen BreatheSmart unit + top rated
  • Super quiet BreatheSmart air purifier (23-49 dB)
  • Has a solid 245 CADR rating
  • Is inexpensive enough; people usually buy 2-3 units for bedroom, kids’ room, and living room
  • Total maximum airflow created is 215 CFM; this is of low importance, however

4. Alen BreatheSmart FLEX Review (Smallest BreatheSmart Air Purifier For Kids Rooms)

smallest alen breathesmart air purifier
Max. Coverage Area: 700 sq ft
CADR Rating: 225
Max. Airflow: 187 CFM
Filters: True HEPA Pure
Filter Lifespan: 12 Months
Power Output: 0.8 – 45 Watts
Noise Levels: 39-55 dB
Dimensions: 25″ x 15″ x 8.5″
(H x W x D)
Weight: 15 lbs
Price: $$$$
Average Rating: 4.5 out of 5 stars

FLEX is the smallest BreatheSmart air purifier. It has a 700 sq ft maximum coverage area; that’s why it’s perfect for kids’ rooms.

The filter is the standard Medical Grade HEPA filter. It removes allergens, dander, mold, dust, and all kind of smoke exceptionally well.

FLEX is powered by up to 45 Watts. That’s enough to create a maximum of 187 CFM airflow with a 225 CADR rating. That’s a higher CADR rating than the bigger FIT50 BreatheSmart unit.

The filters for FLEX are the least expensive. They last for about 12 months; 9 months, if you use it 24h per day.

In addition to the B4-Pure/FL40-Pure HEPA filter (Dust, Mold, Pet Odors), you can choose these specialized filters:

  • FLEX Smoke filter FL40H. Additionally, removed heavy smoke, toxic chemicals (VOCs), wildfire smoke.
  • FLEX OdorCell Filter B4. This is an activated charcoal filter that reduces odor (the kitchen is full of undesired odors, for example).

All in all, FLEX is actually the very best of the first 3 BreatheSmart air purifiers; you can read the full Alen BreatheSmart FLEX HEPA air purifier review here. It’s more appropriate for smaller rooms, such as the bedrooms and kids’ bedrooms.

Alen BreatheSmart FLEX

  • Surprisingly high 225 CADR rating, given 187 CFM airflow
  • Appropriate for small rooms up to 700 sq ft (kids rooms, for example)
  • Has several special filters for smoke, odor, and even heavy smoke (wildfires)
  • It is the cheapest Alen BreatheSmart unit
  • Has a bit high noise level (up to 55 dB on turbo setting)
  • It’s outpaced by it’s similar successor BreatheSmarth 45i (4# review)

5. Alen BreatheSmart FIT50 Review (2nd Best For Standard Bedrooms)

best alen breathesmart air purifier for bedroom
Max. Coverage Area: 900 sq ft
CADR Rating: 220
Max. Airflow: 231 CFM
Filters: True HEPA Pure
Filter Lifespan: 12 Months
Power Output: 1.2 – 60 Watts
Noise Levels: 32-49 dB
Dimensions: 22.25″ x 16.75″ x 10”
(H x W x D)
Weight: 16 lbs
Price: $$$$
Average Rating: 4.5 out of 5 stars

FIT50 is a bit bigger than FLEX; it has a 900 sq ft maximum coverage. It also has a higher airflow (231 CFM) but, quite paradoxically, a lower CADR rating.

A lower CADR rating, of course, is not ideal. So why did the Alen engineers not increase it? Well, because they didn’t want to increase the noise levels.

FIT50 is, in fact, the only old BreatheSmart series air purifier that operates entirely under 50 dB. Its noise levels range from 32 dB (low fan speed setting) to 49 dB (turbo setting). In short, the CADR rating was sacrificed to make a more quiet air purifier.

Noise-wise, it can be compared to the new BreatheSmart 45i and 75i. But there is a reason why those two are more advanced; quite honestly, the FIT50 has lost its 1st place air purifier for a standard-sized bedroom to 45i.

The filtration system is based on the True HEPA filters like all BreatheSmart units. In addition to this basic (Fit50 900SqFt) filter, you can choose:

  • FIT50Aallergies/Dust filter.
  • FIT50 Mold/Bacteria filter.
  • FIT50 OdorCell FF50-MP Pet Dander/Odor filter.
  • FIT50 FreshPlus Smoke/Chemical filter. Primarily against VOCs.

Alen BreatheSmart FIT50

  • The quietest 1st line BreatheSmart unit (32-49 dB)
  • Biggest choices of a particular filter
  • Still enough affordable price even for buying 2-3 units
  • Lower CADR rating (the price of getting noise levels so low)

Overall BreatheSmart Assessment

As we have seen, all Alen Breathesmart air purifiers do their primary job of removing dust particles, smoke, odors, mold, and so on very well. In large part, that is thanks to the brilliant medical-grade True HEPA filtration systems.

HEPA filtration, along with the activated carbon filters, is utilized by almost all air purifier brands, including Coway, Blueair, Winix, Honeywell, GermGuardian, IQAir, Okaysou, Dyson, and Hathaspace, to name just a few.

In fact, the 75i is the best air purifier in 2024.

But the units themselves differ a bit. This has to do with there being 2 BreatheSmart lines:

  • Old(er) line consisting of FLEX, FIT50, and Classic.
  • New line consisting of BreatheSmarth 45i and 75i.

FLEX, FIT50, and Classic are fantastic devices. But the new 45i and 75i are even better; in fact, they are so much better that they can command quite a high price. Financially, that makes them less appealing, but specs-wise they are an engineering marvel.

All in all, you will hardly find a line of air purifiers that is as complete and capable as the Alen BreatheSmart series.

2 thoughts on “5 Best-Of-The-Best Alen BreatheSmart Air Purifiers (2024 Review)”

    • Hello there, Alen Breathesmart air purifiers don’t include the somewhat questionable UV filters, and as such, do not emit ozone.


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