Alen BreatheSmart 75i review: a powerful air purifier for large spaces

Alen BreatheSmart 75i: two-minute review

While there are plenty of air purifiers on the market, most of them don't come with the power of the Alen BreatheSmart 75i. This model stands out for being suitable for larger spaces – up to 1,300 square feet. In fact, Alen advertises that, at its highest setting, this model can completely cycle through the air in a room in 30 minutes. For that level of suction alone I think it's a worthy contender for inclusion in TechRadar's best air purifier ranking. 

Power isn't the only thing the Alen BreatheSmart 75i has going for it, though. It's available with three different HEPA filters, and it's easy to use with its capacitive controls, an LED indicator for current air quality, and the ability to track your space's air. For more remote control there's app support, although it's strangely well hidden.

The build quality is high and the design is attractive if understated, falling more on the discreet side of air purifier aesthetics. You can change out the faceplate for different colors, to blend in or match your decor. It's also very easy to set up – you basically pull it out of the box and remove some wrapping it's ready to go. 

This is the bigger sibling of the 45i (which I've also tested – review incoming) and it functions in almost the exact same way. There are just two key differences: it delivers slightly more powerful performance, and it's more expensive. That brings me to this model's two main potential drawbacks. When it's pulling in a lot of air at its highest settings, things can get a bit loud. And it's not cheap – you could probably buy seven smaller air purifiers for the cost of one Alen BreatheSmart 75i. If you don't need to clean a large space, this purifier is overkill; but if you do, and can afford the price tag, it's hard to fault. Read on for my full Alen BreatheSmart 75i review.

Alen BreatheSmart 75i air purifier review: price & availability

• Prices from US $749
• Different filters and front panels cost extra
• Available now in US only

With a starting price of $749 (about £590 / AU$1150), the Alen BreatheSmart 75i is far from cheap. (Even the smaller 45i cost from $429.) It's available to buy direct from Alen, but also via Amazon.

If you wish to upgrade the front panel to anything besides white, that's going to cost an extra $39. And going from the basic 'Pure' HEPA filter to the 'Fresh' filter adds $30, while upgrading to the 'Odor' filter adds $40. You could be looking at up to an extra $818 (about £650 / AU$2150) if you want all the upgrades.

It's a bit tough to compare the Alen BreatheSmart 75i to the competition as most models are designed for smaller spaces, and are much cheaper. Costwise at least, it's roughly in line with the Dyson Purifier Hot+Cool Formaldehyde HP09 (retail price: $769.99 / £699.99 / AU$1,149). It's meant for a slightly smaller space – a little over 800 square feet – but it does include both heating and cooling as well as the ability to take care of carcinogenic formaldehyde, something that the 75i doesn't do with its most basic filter. However, the Alen BreatheSmart 75i can automatically change its cleaning level according to the surrounding air quality, something that the Dyson doesn't offer.

The Alen BreatheSmart 75i is only available in the US.

• Value for money score: 4 out of 5

Alen BreatheSmart 75i specs

Alen BreatheSmart 75i air purifier review: design

• Discreet but sleek aesthetic
• Easy capacitive controls for full functionality
• Has three different filters to choose from

Aesthetically, the Alen BreatheSmart 75i is on the discreet side, eschewing the more space-age look of some other pricey air purifiers. It's basically a large box-shaped appliance with a bit of ergonomics thrown in. Its white and black colorway reminds me a little of EVE from Wall-E, though there are currently five other different-colored front panel options to choose from if the white doesn't fit with your decor. Either way, it looks sharp, but in a non-obtrusive way.

Some cool design features include an indentation around the base of the unit, where you can neatly wrap any excess cabling from the power cord, and a handle on the upper back for easy lifting. Also, those front panels are held on by magnets so it's about as easy as it can get to pull it off to get to the filter, whether you're replacing it or setting up for the first time.

Functionally, all the controls sit atop the unit and are of the capacitive variety. They're responsive and offer basically all of the unit's functionality without having to dig into the app. You can turn on the ionizier, check and reset filter levels, adjust the brightness of the button lights and LED indicator, adjust speed, switch on an automatic mode (where the unit will adjust according to air quality level), and lock in current settings so there are no accidental presses. That last one is a necessary feature, because the buttons are ultra-sensitive.

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Sitting in the middle of the control panel is an LED indicator encircling the power button. It changes color depending on the air quality, so you can see at a glance the level of contaminants in the room. While this is a powerful air purifier, I have seen it reach its highest level (purple) before – at which point I decided to open a window to assist.

If you prefer, you can control the Alen BreatheSmart 75i remotely via the app. The only additional functionality available here is that the app tracks usage and logs cleaning history. The fact that you're not locked out of any key features if you're not using the app is actually good, in my opinion – not least because the fact that there even is a companion app was not apparent to me right away.

While the Alen BreatheSmart 75i is bigger than the 45i, it's slightly more limited when it comes to the filters that are available. Instead of having four different filters to choose from, there are three. There's the 'Pure' one, which is the basic H13 HEPA filter and the one included with my review unit, a 'Fresh' one that adds carbon to capture VOCs (volatile organic compounds) and chemicals that the 'Pure' might not capture, and, lastly, there's the 'Odor' filter that adds in an odor neutralizer. Everything beyond the 'Pure' comes at a small upcharge. Also of note, Alen offers a subscription program where it will send you a new filter every nine months (typically the end of a filter's life cycle).

• Design score: 4.5 out of 5

Alen BreatheSmart 75 air purifier review: performance

• Setup is straightforward
• App support is not immediately apparent
• Powerful performance designed for large rooms

Let's start this section by discussing setup. It's so easy that you won't even need to crack open a manual. All you have to do is remove the purifier from the box, pull the front panel off (this is magnetically held into place, so doesn't require a lot of pressure), pull the tab out at the top of the filter to take it out, remove its plastic casing, put the filter back in, and remove the paper band off the front panel. Plug it in and you're good to go. It takes maybe five minutes to go from in-the-box to in use.

Setting up the app is pretty straightforward as well… at least, once I realized it had app support. There's nothing on the unit to indicate that this air purifier has app support – the Wi-Fi symbol indicator can only be seen once connected to the app. Even the manual doesn't mention it. Pairing the BreatheSmart 75i with the app requires holding down one of the capacitive buttons, which is not labeled as such, to start the process. Once you've done that, however, the setup through the app is straightforward.

Since this is the performance section of my review, let's talk about the actual performance. The review unit came with the basic 'Pure' filter so there are no odor neutralizers involved here. If that's part of your concern beyond just having clean air, make sure to upgrade to the appropriate filter.

To that point, this air purifier was used in a family member's apartment after they had unwittingly sublet it to a smoker. They ran the Alen BreatheSmart 75i and it got rid of a lot of stale air. However, the smell of cigarettes did linger a little.

Beyond that, I can say that the Alen BreatheSmart 75i does a great job even without the odor neutralizer. The indicator is very reactive and lets me know right away when the air quality has dropped. I prefer using the air purifier on Auto mode, so it will adjust as needed to the air quality.

When run on turbo, the BreatheSmart 75i can pull in a lot of air. It can completely clean the air in up to 1300 square feet in 30 minutes when on turbo, and has a CADR of 347 cfm (cubic feet per minute). That means that it comes quite a bit of airflow with a strong filter to do the job it's meant to.

Beyond refreshing a stale-smelling apartment, I've also used the Alen BreatheSmart 75i with incense, flatulent family members, and cooking, to see it kick into action fairly quickly and work efficiently. While I don't have a real-world way to test the ionizer, which is designed to slow down viruses and bacteria, I do keep it on and appreciate the fact that it is included.

• Performance score: 4.5 out 5

Should you buy the Alen BreatheSmart 75i?

Buy it if...

Don't buy it if...

Alen BreatheSmart 75i review: also consider

If our Alen BreatheSmart 75i review has you considering other options, here are two air purifiers to consider...  

Alen BreatheSmart 45i
The Alen BreatheSmart 45i is very similar to the 75i, but is designed for smaller spaces and costs less. It also has one more filter option – VOC/Smoke, which has extra carbon, designed specifically for dealing with noxious gases.

Dyson Purifier Hot+Cool Formaldehyde HP09
This air purifier from Dyson will cost you; but it's powerful, can tackle formaldehyde, heats as well as cools, and comes with quite a few smart features.
Read our full Dyson Purifier Hot+Cool Formaldehyde HP09 review

How I tested the Alen BreatheSmart 75i air purifier

• Tested for two months
• Used incense, candles, and stale air to test
• Tried all the different functions, including the app

To test the Alen BreatheSmart 75i, I used it for a month to see how it would fare in the living room as well as a whole one-bedroom apartment. I intentionally put it in areas of strong odors to see how it would perform, and delved into the app to see what functionality it offered.

Having used it over this period I can conclude that this is a powerful air purifier, working particularly well in larger spaces. That said, you'll need to upgrade the filter if you care about completely killing odors.

I've spent the past few years reviewing tech gear for the home, where I've gotten a feel for what to look for and how to put a piece of kit through its paces to see whether it's worth the recommendation.

• First reviewed March 2024