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Alen BreatheSmart 45i Review

Last updated January 28, 2023

This post may contain affiliate links.

Author
Author avatar Paul Allen

Paul is our go-to-guy for air purifier and dehumidifier reviews. His apartment has become a de facto HouseFresh test lab where he pits the latest clean air technology against the perils of city center life. When he’s not putting a purifier through its paces, Paul likes to endlessly dig through dusty record shops (making his dust-free apartment even more important).

Our verdict:

The Alen BreatheSmart 45i performed excellently, cleaning our test room of all particle pollutants in 33 minutes.

Although its price comes in at the higher end of the mid-range market, you’ll struggle to find another purifier for under $450 that boasts 5 air changes per hour in an 800 sq. ft room with a CADR rating of 245, along with the real-world performance to back it up. The smart features include App support and an accurate auto mode that switches on when it detects pollutants in the air. It runs on average quieter than air purifiers with similar clean performance and is backed with a lifetime warranty as long as you purchase a filter subscription.

Let’s delve deeper into what makes this unit an excellent option for mid-sized rooms and apartments.


For our latest review, we’ve turned to the Austin-based air purifier manufacturer Alen to put the BreatheSmart 45i through its paces. Alen is widely regarded as one of the top innovators on the market, creating high-performing purifiers and long-lasting filters. 

The BreatheSmart 45i is the little brother to Alen’s flagship purifier (the 75i), sharing the same great technology but designed for use in spaces up to 800 sq. ft. With impressive facts and figures on the Alen website, we decided to test it for ourselves. As with all the reviews we do here at HouseFresh, we bought the Alen 45i with our own money to be as unbiased as possible to give our readers the information they need to decide if this unit is for them.

Alen 45i Air Purifier, Quiet Air Flow for Large Rooms, 800 SqFt, Air Cleaner for Allergens, Dust, Mold, Pet Odors with Long Filter Life (Dust, Mold, Odor) (Air Purifier)
  • REPLACEMENT AIR FILTER: For BreatheSmart Flex & 45i Air Purifiers ONLY. Find your model number on the top panel below the power button to ensure you get the right HEPA filter. It purifies 800sqft every 30 minutes and is helpful for 9-12 months.
  • B4-PURE FILTER: Ideal for medium, large, and extra-large spaces, including living rooms, bedrooms, nurseries, laundry rooms, bathrooms, offices, kitchens, basements, and more! It traps allergens, pollen, fur, pet dander, mildew, and aerosolized viruses.
  • MEDICAL-GRADE PROTECTION: 3-Stage H13 True HEPA filtration captures 99.99% of particles as small as 0.1 microns. HEPA air filtration is the third of five stages where the air filter traps viruses, bacteria, mold spores, and smoke with activated carbon.
  • 5 AIR QUALITY COLORS: A Laser Smart Sensor detects airborne particles and auto-displays the current air quality. Blue = Excellent, Green = Good, Orange = Fair, Red = Poor, Purple = Bad air quality (high particle levels).
  • PERFECT GIFT WITH A RANGE OF APPLICATIONS: Alen air purifiers aim to maintain our community’s health and wellness with cleaner pure air. From back-to-school preparations for classrooms, doctor’s offices, hotels, bars, lounges, restaurants, and most importantly your home, our air purifiers offer air filtration to everyone. A great gift for smokers and pet owners who need to improve their indoor air quality caring for their loved ones.

Alen 45i Air Purifier Specifications

Air Purifier
Alen BreatheSmart 45i
CADR
245
Technology
H13 True HEPA + Activated Carbon
Room Size
800 sq. ft
Weight
20.1 lbs
Filter Life
12 months
Noise Level
23 dB to 49 dB
Monthly Energy Consumption
Up to $4.40
More information
Price
$428.98
Air Purifier
Alen BreatheSmart 45i
CADR
245
Technology
H13 True HEPA + Activated Carbon
Room Size
800 sq. ft
Weight
20.1 lbs
Filter Life
12 months
Noise Level
23 dB to 49 dB
Monthly Energy Consumption
Up to $4.40
More information
Price
$428.98

The Alen 45i Look

The Alen BreatheSmart 45i has a sleek and modern aesthetic, combining a glossy white facade with gun-metal gray trim for a minimalist and versatile look. 

Despite being a powerful machine, it doesn’t take up too much space and as far as white goods go, sits comfortably in my living space, bedroom or office. Due to its relatively lightweight, it’s easy to maneuver from room to room and can slot nicely into the corner or a cupboard when not in use. 

For those after a more distinctive appearance, the Alen Breathesmart is available in a variety of ‘designer’ faux woodgrain and metallic tones so you can best match the decor of your home.

How to use the Alen 45i

Getting the purifier up and running is ridiculously simple. Once everything is unwrapped, open the front hatch via the air inlets on the side of the machine and slot in the HEPA filter, with the pre-filter facing towards you. Then once connected to mains, hit the power button, and you’re good to go.

With the purifier turned on, I first noticed the power button illuminate. Rather than a mere design feature, this light’s color indicates the air quality in the room. There are five colors in total, from purple, which is poor through to red, orange, green, and finally, blue, which signals excellent air quality. 

The capacitive control panel allows you to cycle through the settings easily. Changing between the four fan speeds, adjusting the LED lights from low to high or even off entirely (which comes in handy at bedtime), or set to Auto, which monitors the air quality and adjusts the purifier’s settings for you automatically (we’ll get into that later). 

As well as a handy filter replacement light, which illuminates yellow when the filter is coming to the end of its lifespan and turns red when it is time to replace, you can also lock the control panel to stop any curious kids or boisterous pets from messing with your new pride and joy.

Filter options for the Alen Beathsmart 45i

When purchasing the Alen Breathsmart 45i, you are also given a range of filters. Each filter offers a slightly different level of protection, mainly in relation to odors and volatile organic compounds (VOCs). I went for the ‘Fresh’ model, which contains a medical-grade H13 True HEPA filter plus an activated carbon filter for added protection against VOCs and smoke.


Each of Alen’s True HEPA filters can capture 99.99% of airborne contaminants down to 0.1 microns, which are certainly impressive figures and was something we saw for real in our performance tests. However, these results reflect controlled lab testing, so I was keen to see how these figures translate in the real world. 

Alen Air Filter Replacement For BreatheSmart 45i Or Flex, True HEPA Basic Air Purifier Filter For Allergens, Pollen, Dust, Dander, And Fur, HEPA Filter Replacement For Better Indoor Air Quality
Alen Air Filter Replacement for BreatheSmart 45i or Flex, True HEPA Basic Air Purifier Filter for Allergens and Dust, HEPA Filter Replacement for Better Indoor Air Quality, Pure Air Filter for Smoke
Alen Air Filter Replacement for BreatheSmart 45i or Flex, True HEPA Basic Air Purifier Filter for Allergens, Pollen, Dust, and Household Odors, HEPA Filter Replacement for Better Indoor Air Quality
Alen Air Filter Replacement for BreatheSmart 45i or Flex, True HEPA Basic Air Purifier Filter for Dust, Mold, and Pet Odors, Filter Heavy Smoke, HEPA Filter Replacement for Better Indoor Air Quality
Technology
Basic model covering: Allergy and Asthma Triggers (dust, dander, pollen) and Pollution
Standard model covering: Chemical toxins (VOCs), Household Odors, Allergens (dust, dander, pollen) Pollution Activated Carbon: Targets indoor and outdoor pollutants (VOCs) & smoke, leaving air smelling fresh.
For homes with pets and kids, covering: Household Odors, Pet Odors, Allergens (Dust, Dander, Pollen) Destroys Odors: Nontoxic technology eliminates bad smells at the molecular level
With the most activated carbon of any filter in its class (2.3 lbs.) covering: Heavy Smoke, Chemical Fumes, Allergies, (Dust, Dander, Pollen) Safety from Smoke: Activated carbon targets dangerous ultrafine particles as small as 0.1 microns and toxins (VOCs)
Price
$69.00
$89.00
$81.43
$119.00
Filter
Alen Air Filter Replacement For BreatheSmart 45i Or Flex, True HEPA Basic Air Purifier Filter For Allergens, Pollen, Dust, Dander, And Fur, HEPA Filter Replacement For Better Indoor Air Quality
Technology
Basic model covering: Allergy and Asthma Triggers (dust, dander, pollen) and Pollution
More information
Price
$69.00
Alen Air Filter Replacement for BreatheSmart 45i or Flex, True HEPA Basic Air Purifier Filter for Allergens and Dust, HEPA Filter Replacement for Better Indoor Air Quality, Pure Air Filter for Smoke
Technology
Standard model covering: Chemical toxins (VOCs), Household Odors, Allergens (dust, dander, pollen) Pollution Activated Carbon: Targets indoor and outdoor pollutants (VOCs) & smoke, leaving air smelling fresh.
More information
Price
$89.00
Alen Air Filter Replacement for BreatheSmart 45i or Flex, True HEPA Basic Air Purifier Filter for Allergens, Pollen, Dust, and Household Odors, HEPA Filter Replacement for Better Indoor Air Quality
Technology
For homes with pets and kids, covering: Household Odors, Pet Odors, Allergens (Dust, Dander, Pollen) Destroys Odors: Nontoxic technology eliminates bad smells at the molecular level
More information
Price
$81.43
Alen Air Filter Replacement for BreatheSmart 45i or Flex, True HEPA Basic Air Purifier Filter for Dust, Mold, and Pet Odors, Filter Heavy Smoke, HEPA Filter Replacement for Better Indoor Air Quality
Technology
With the most activated carbon of any filter in its class (2.3 lbs.) covering: Heavy Smoke, Chemical Fumes, Allergies, (Dust, Dander, Pollen) Safety from Smoke: Activated carbon targets dangerous ultrafine particles as small as 0.1 microns and toxins (VOCs)
More information
Price
$119.00

Performance Testing

As part of all the reviews we do here at HouseFresh.com, we tested the Alen 45i air cleaning performance by filling our test room with incense smoke and then recording how quickly this air purifier can remove PM1, PM2.5 and PM10, the tinniest particles that can cause the most damage as they easily enter our bodies via our lungs. We use a Purpleair Indoor sensor with our in-house custom API recording software and then share this data via Flourish.

You can see here what happened during our test of the Alen 45i:

When we switched on the Alen 45i at full power with the ionizer, it removed all particles in 33 minutes.

This was the same time as the Levoit Core 400S and the budget Taotronics AP-003 but 3 minutes quicker than the Mila Air Purifier. The 45i has great performance for a smaller to a medium-sized room but would not be the best choice for a larger room, which is why the Alen 75i exists, which managed to clean our test room in 24 minutes.

Filter Replacement 

Even if used continuously, running the purifier as recommended, Alen claims the filter will last 12 months. This is quite a long lifespan for a HEPA filter, with many other manufacturers suggesting replacing the filter after 6 months or a year if used infrequently. However, as the replacement filters cost up to $119.00, I hope it proves true. It will certainly be interesting to monitor the performance over the year to see how well the filter holds up.

Alen Air Filter Replacement for BreatheSmart 45i or Flex, True HEPA Basic Air Purifier Filter for Dust, Mold, and Pet Odors, Filter Heavy Smoke, HEPA Filter Replacement for Better Indoor Air Quality
  • REPLACEMENT AIR FILTER: For BreatheSmart Flex & 45i Air Purifiers ONLY. Find your model number on the top panel below the power button to ensure you get the right HEPA filter for your unit. Install and breathe well-filtered air in no time.
  • FL40-H FILTER: The FL40-H filter eliminates smoke with 2 lbs of activated carbon, enabling the air purifier filter replacement to absorb heavy smoke, wildfire, harmful airborne particles, household chemicals, VOCÕs, and more.
  • TRUE HEPA: 3-Stage H13 True HEPA filtration captures 99.99% of particles as small as 0.1 microns. HEPA air filtration is the third of five stages where the air filter can trap viruses, bacteria, mold spores, and smoke with activated carbon.
  • EXTRA LONG FILTER LIFE: With Alen HEPA air purifier replacement filters, you may only need to change the air filter every 9-12 months. Pure air replacement filters can trap as many air particles for longer for better indoor air quality you can enjoy.
  • Our standard medical-grade H13 True HEPA air filter offers outstanding protection by removing 99.9% of dust, allergens, and harmful fine pollutants as small as 0.1 microns. Every 30 minutes, our product can purify your home or office air depending on the model of Alen air purifier.

Noise

With four fan speeds to choose from, the noise of this purifier can easily be curtailed to suit the user while still vastly improving the air quality in your home. 

As a light sleeper, I thought utilizing the purifier in the bedroom would be a no-go area. However, I was pleasantly surprised to find on the lowest setting, it is barely noticeable. I also had no issues on the second lowest setting, which may have even helped send me off to sleep with its gentle ASMR pink noise hum. 

During the day, with the purifier set to auto, it occasionally ramped up the fan speed to higher levels. This creates a lot of noise and can be distracting, especially if working or even watching TV or listening to music. Of course, this can easily be adjusted to suit the user and limited to lower speeds when needed. 

Alen states the sound levels of the purifier are 39 dB at speed 1, 42 dB at speed 2, 49 dB at Speed 3, and reaching 55 dB on turbo. To you and me, that ranges from a whisper on the lowest level to a box fan on the highest. 

So you can see and hear for yourself, check out our sound guide below:

Cost of Running

Thanks to its Energy Star-rated efficiency, running this purifier will cost less than you think, even if you leave it on auto to work its magic around the clock, as Alen recommends. The purifier consumes 50 watts of energy at full power, which will set you back at approximately $4.40 per month. In reality, the power consumed will be much, much lower as the purifier operates on the lowest setting 99% of the time.

While the Alen Breathesmart 45i proves to be highly efficient in energy use, filter replacement costs are considerably increased by average running costs. Ranging from $69.00 for a basic filter to $119.00 for the premium option, this is a notable expense to be paid out and should be seriously considered before purchasing. 

Feel feel to read more about the electricity cost of air purifiers, and we compare how the 45i costs in comparison with other similar air purifiers in this range.

Pros

  • Its minimalist design helps it blend nicely into my home.
  • It is surprisingly lightweight, making it easy to move from room to room.
  • It’s quiet enough to run through the night, allowing me to sleep soundly.
  • The ionizing feature is optional, so it can be switched off if you have respiratory issues. 
  • It comes with a lifetime warranty

Cons

  • The replacement filters are expensive
  • The cheapest filter option doesn’t have an activated carbon filter.
  • Being provided with 3 different power cables for various regions is unnecessary and wasteful.

Bottom Line

Upon opening the box to the purifier, you’re met with a simple one-sheet instruction manual, with the header “PREPARE TO CHANGE YOUR AIR” written across the top in large letters. Having researched plenty of air purifiers in the past, I was well aware of Alen’s stellar reputation and knew that their range of products was some of the best in the business. This all contributed to some rather lofty expectations on my part, and I wondered, could this purifier transform the air quality in my city center apartment?

By putting it through its paces in various real-world tests, it proceeded to tick all the boxes. Working well at eliminating odors from cooking and nearby breweries and noticeably reducing allergies to pollen and dust while being extremely simple to operate and maneuver around the home.   

Of course, this performance comes at a cost (both with the initial purchase and with steep filter replacement costs), but its performance backs up its price tag and is helped by being very energy efficient and quiet. I’m pleased to say it has lived up to the expectations of an Alen product. 

For those looking for a quiet and powerful purifier for under $450.00 and are happy to pay extra for the lifetime guarantee and smart features, the Alen Breathesmart 45i could be the air purifier for you. Suppose you are based in the United States. In that case, I recommend you check out the unit at Alen.com as you get automatic registration for their lifetime guarantee, you also get more options to choose your initial filters, and they often have the best price.

Alen 45i Air Purifier, Quiet Air Flow for Large Rooms, 800 SqFt, Air Cleaner for Allergens, Dust, Mold, Pet Odors with Long Filter Life (Dust, Mold, Odor) (Air Purifier)
Alen FIT50 Air Purifier, Quiet Air Flow for Large Rooms, 900 SqFt, Air Cleaner for Allergens, Dust, Mold, Pet Dander, Heavy Odors with Long Filter Life
Alen BreatheSmart 75i Large Room Air Purifier, Medical Grade Filtration H13 True HEPA for 1300 Sqft, 99.9% Airborne Particle Removal, Allergies, Odor & Smoke Air Purifier, Long Filter Life, White
Technology
H13 True HEPA + Activated Carbon
H13 True HEPA + Activated Carbon
H13 True HEPA + Activated Carbon
CADR
245
220
347
Room Size
800 sq. ft
900 sq. ft
1300 sq. ft
Filter Life
12 months
12 Months
15 Months
Price
$428.98
$474.00
$769.00
Air Purifier
Alen 45i Air Purifier, Quiet Air Flow for Large Rooms, 800 SqFt, Air Cleaner for Allergens, Dust, Mold, Pet Odors with Long Filter Life (Dust, Mold, Odor) (Air Purifier)
Technology
H13 True HEPA + Activated Carbon
CADR
245
Room Size
800 sq. ft
Filter Life
12 months
More information
Price
$428.98
Direct from Alen
Air Purifier
Alen FIT50 Air Purifier, Quiet Air Flow for Large Rooms, 900 SqFt, Air Cleaner for Allergens, Dust, Mold, Pet Dander, Heavy Odors with Long Filter Life
Technology
H13 True HEPA + Activated Carbon
CADR
220
Room Size
900 sq. ft
Filter Life
12 Months
More information
Price
$474.00
Direct from Alen
Air Purifier
Alen BreatheSmart 75i Large Room Air Purifier, Medical Grade Filtration H13 True HEPA for 1300 Sqft, 99.9% Airborne Particle Removal, Allergies, Odor & Smoke Air Purifier, Long Filter Life, White
Technology
H13 True HEPA + Activated Carbon
CADR
347
Room Size
1300 sq. ft
Filter Life
15 Months
More information
Price
$769.00
Direct from Alen

Last update on 2023-02-04 / Affiliate links / Images from Amazon Product Advertising API