Alen BreatheSmart 75i Air Purifier Review – Our Hands On Test

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Alen BreatheSmart 75i Air Purifier

Our Rating:

Key Features:

Energy efficient

Low noise output

Built-in air quality indicator

Lifetime guarantee

User-Friendly, Uber Smart Air Purifier You Can Afford to Leave Running 24/7

If you’ve been searching for a powerful air purifier that you can use all day and night, you’ve just found it. The Alen BreatheSmart 75i combines a host of amazing features with low maintenance costs and superb energy efficiency to deliver a product that’s a pleasure to use and easy on the wallet.

A real-time built-in air quality monitor tells you exactly how pure your air is while the associated auto mode function automatically raises or lowers the fan speed to keep your air perfectly clean 24/7. And you can track it all on your smartphone thanks to the 75i’s Wi-Fi connectivity.

Combine these and a ton of other great features with a powerful H13 true HEPA filter and built-in ionizer, and you’ve got a machine capable of purifying spaces up to 1,300 square feet.

For those serious about optimizing the air quality in your home, we suggest bundling the BreatheSmart 75i with the Alen Air Quality Monitor for real-time air quality data throughout your house delivered straight to your phone.

Shop now with our special ESSENTIAL7 code and receive 7% off your purchase.

Review Criteria Ratings

Air Purifying Performance4.5/5
Build Quality5/5
Maintenance and Upkeep5/5
Operating Costs5/5


  • H13 True HEPA with ionizer
  • Very low noise output
  • Extremely energy efficient
  • Built-in air quality monitor with color-coded display
  • Wi-Fi connectivity and intuitive phone app


  • A little bulky
  • Full filter replacements required
  • Filter comes loose easily

Should You Buy It?

If you’re in need of a powerful air purifier for large spaces, then there’s no better choice than the Alen 75i. This smart purifier has all the functionality you’ll ever need, powerful air filtration, and superb energy efficiency that puts the competition to shame.

Disclosure:It is important you understand that we may receive commissions when you click our links and make purchases. However, this does not impact our reviews and comparisons. All opinions are our own we pride ourselves on keeping our articles fair and balanced. For more info see our disclosure statement.

BreatheSmart 75i Air Purifier Overview

The Alen BreatheSmart 75i is the largest in the BreatheSmart line. It has a coverage rating of 1,300 square feet and a CADR of 347. The smaller 45i is rated for spaces up to 800 square feet with a CADR of 245. The BreatheSmart line includes three older models, but none of these feature the Wi-Fi connectivity that really sets this newer generation apart.

Similar to the 45i, the 75i comes with a ton of useful features. It has a built-in air quality monitor and auto function that work together to automatically adjust the fan speed based on the quality of the air in your home. The unit has five fan speeds in total, as well as a timer function, light’s out mode, and ionizer function.

Alen Air Monitor on top of the BreatheSmart 75i

The standard filter that comes in these units is an H13 true HEPA filter. But you can easily upgrade to an H13 that also includes activated carbon and additional odor and VOC tackling technology.

With the free Alen app, you can easily connect the 75i to your smartphone for real-time monitoring of your indoor air quality. You can also use the app to control your purifier from anywhere.

This same app is utilized by the Alen Air Quality Monitor, which allows you to check air quality without running a purifier. This little unit makes a great addition to the 75i for those interested in optimizing their indoor air quality. In fact, if you bundle the 75i and the air monitor, you’ll receive over $100 in savings.

With our ESSENTIAL7 discount, you can add an additional 7% savings on top of that.

Like all Alen products, when you purchase the BreatheSmart 75i, you’ll receive a lifetime guarantee on the product and hassle-free replacements if anything ever goes wrong.

The 75i certainly has a lot of great features and all the necessary parts to perform well, but how does this air purifier stack up to the competition?

I had the chance to test the Alen 75i in my own home. Keep reading to find out where I was impressed, where the unit fell short, and to see my full Alen BreatheSmart 75i review.

How The 75i Performs

I have tested a ton of air purifiers in my home, and I have to say, the Alen BreatheSmart 75i really took me by surprise. I knew this would be a quality machine that performed well, but I didn’t know just how much I would like it.

Air Purifying Performance

picture of Alen BreatheSmart 75i on the floor and a photo of the filter’s back

I received the 75i with an upgraded Pet/Odor filter installed. This filter contains the same H13 True HEPA that makes up the standard filter, but with additional “nontoxic technology” that destroys odors on contact.

What this “nontoxic technology” includes, exactly, is not explained on the company’s website. Like the upgraded Fresh filter, I assume it contains activated carbon. But what else sets these two options apart, I can’t say.

With the upgraded filter in place, I ran a number of tests. The first was to pit the unit against my neighbor’s cigarette smoke that comes through the windows every morning.

I had the unit running on auto mode. The moment I smelled the smoke I noticed the blue light on the purifier, indicating excellent air quality, flashed to orange, indicating the air had fallen to fair quality. As the purifier kicked up to tackle the smoke, I closed the windows.

Within ten minutes all noticeable smoke smell was gone and the air quality in my living room was back to blue.

I also tested the unit in my bedroom after unboxing a cheap foam mattress. The foam put off a terrible chemical smell. For the first test, I ran the unit without the ionizer on. After two hours locked in the bedroom with the mattress, the chemical scent was still very apparent.

I repeated the test with the ionizer on and got moderately better results.

In terms of overall performance, I found the 75i worked very well to remove smoke, smoke odors, and fine particles from the air. But, even with the ionizer active, it seemed to struggle with VOCs. For this, you need to upgrade to the Fresh filter which includes a layer that targets volatile organic compounds.

It’s also worth mentioning that the built-in air quality monitor only reacts to fine particles. Tiny particles like odors and VOCs do not trigger it. That means when you’re battling these kinds of air issues, you’ll need to manually set the fan speed rather than relying on auto mode.

Build Quality

pictures showing the side airtakes and exhaust panel of the Alen BreatheSmart 75i

It was apparent from the moment I unboxed my 75i that these purifiers are built incredibly well. They are all plastic but appear very durable. They also feature some smart design aspects that make them highly usable.

For one, the air intakes are positioned on the side with the exhaust on the top, so the unit can be placed against the wall to save space. And the front panel features magnetic closures that make it super easy to get the panel off and on.

This front panel is available in six different finishes, so you can match your home’s aesthetic. This is important because the 75i is a substantial unit that will take up some space in your room.

The only issue I noticed with the physical aspects of the unit was that the filter would easily get knocked out of place just about every time I moved the purifier. This movement was slight and wouldn’t have affected the filter’s performance, but it was enough to trigger the filter sensor, causing the unit to be unresponsive when I tried to turn it on.

Maintenance and Upkeep

installing the filter of the Alen BreatheSmart 75i

Upkeeping the 75i is impressively easy.

As with all purifiers, a weekly wipe-down of the outer surface with a dry rag and vacuuming of the outer filter screens will help the unit last longer.

The filter itself is one piece, which means you have to replace the entire thing at once. Normally, I would see this as a major disadvantage, given that some layers of the filter will naturally last longer than others. But, in this case, the filter does not include distinct layers and, more importantly, lasts a long time as is.

You will only need to replace your Alen filter once every 12 to 15 months. This is twice the lifespan of most purifier filters.

Buying a new $99 filter (or $130 filter for the upgraded options) once per year is not bad at all in terms of maintenance costs.


control panel of the Alen BreathSmart 75i Air Purifier

The 75i has a ton of great features that make it highly useful. It has a timer mode, five fan speeds, and a highly useful auto-mode setting.

Plus, the air quality indicator light on the sleek digital control panel makes it easy to see the quality of your air. And because of the Wi-Fi connectivity and associated app, you can even check on that air quality from afar. I also love that you can use the app to control the unit no matter where you are.

One quirk I did notice with the app is that the air quality reading I saw on my phone was not always the same as what the unit showed on its control panel. There were multiple times when the purifier showed an orange reading but the phone app never showed anything above green.

Beyond the features of the unit, there were two things that really added to its usability.

First, it is incredibly quiet. On the low setting, it puts off just 25dB. That is about the same as your typical household background noise level. On turbo speed, that level went up to 45dB according to my measurements. This was actually less than the advertised noise output of 49dB, making it the first noise output overestimation I’ve ever encountered.

Either way, this unit is impressively quiet.

Secondly, the unit features a night mode setting that allows you to turn off all the lights while keeping the unit running. To do this, simply tap the power button after turning the unit on. To turn the unit all the way off, you must hold the power button or tap it twice.

Operating Costs

One of the worst things about air purifiers is that they are really only useful if you leave them running. After all, the quality of the air in your home changes constantly with different activities and the outdoor air quality. If your purifier is not energy efficient, this can translate to high utility bills.

Luckily, the BreatheSmart 75i is not only Energy Star Rated, but it’s mind-blowingly energy efficient.

Most air purifiers use between 8 and 130 watts, with the average unit using about 50 watts on standard fan mode. According to my direct measurements, the 75i uses just over 5 watts on low fan speed and only 25 watts on turbo mode.

Even on its highest speed setting, it uses less energy than the average unit set to medium—that’s pretty impressive!

This means that if you left your unit running 24/7 all month long, you’d only be spending an additional $0.40 per month at best and $2.00 at worst. Not a bad investment at all for cleaner air!

Alen BreatheSmart 75i Air Purifier Alternatives

The Alen BreatheSmart 75i is a highly usable purifier that is affordable and effective. But, if you’re after a unit that is better equipped to tackle VOCs straight out of the box or that’s a little less expensive upfront, then there are other options.

The Enviroklenz Mobile UV Air Purifier has a proven track record when it comes to tackling VOCs as well as most other airborne pollutants. This large purifier is rated for rooms up to 1,000 square feet and includes a UV mode that is especially effective for neutralizing pathogens.

If what you need is a more affordable purifier for your large bedroom or living space, the Okaysou Apollo 630 is a great choice. This very well-priced purifier is light on features but has a powerful true HEPA filter with activated carbon that works very well to neutralize odors and capture fine particles.

FeaturesAlen BreatheSmart 75i Enviroklenz Mobile UV Air PurifierOkaysou Apollo 630
Room size rating1,300 sq ft1,000 sq ft800 sq ft
Filter typeH13 True HEPA with optional extrasHEPA filter, earth mineral cartridge filter, UV lightsDetachable pre-filter, H13 True HEPA, activated carbon
Best FeatureWi-Fi enabled with built-in air quality monitorPowerful VOC and pathogen filtrationHighly affordable


A quality air purifier is a great way to improve the air in your home and keep your family healthier. Finding a unit that is energy efficient and built to be highly useful will save you money and headaches while cleaning your air.

The Alen BreatheSmart 75i is not only capable of powerful air filtration, but it uses almost no energy and has a ton of great features. The built-in air quality monitor and Wi-Fi capabilities give you peace of mind wherever you are while the auto-mode function, customizable front panel, and long-lasting filters make this appliance a joy to use.

To learn more about the Alen BreatheSmart 75i, click here.

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Sara Seitz is a freelance writer and novelist. She lives with her husband and wildling toddler in Colorado where she spends her days working on their house, gardening, and reconnecting with nature.