Alen BreatheSmart 45i air purifier review: powerful and easy to use

Alen BreatheSmart 45i: two-minute review

The Alen BreatheSmart 45i is just one of many air purifiers on the market. And, if you’re like me when it comes to tech that doesn’t exactly tickle the dopamine receptors, it’s easy to skip the reviews and simply opt for something from your nearest big box store. However, when it comes to air purifiers, you probably shouldn’t do that.

Not only are you in the market for something that literally cleans the air you breathe, but many of the best air purifiers are either unlikely to be available from that big box store – or, if they are, will go for a price that will make you want to reach for something on a lower, cheaper shelf.

Quality is key when buying an air purifier, then. Having spent a month, if not more, with the Alen BreatheSmart 45i, I’d say that it definitely fits that category of product.

Instead of the space-age design of even pricier models, this model is sleek and discreet. And, unlike more budget options, it’s obviously well designed and made. This is before you consider the fact that you can switch out the front panel for a handful of options to match your decor, and choose from four different filters to best meet your needs.

There really isn’t much not to like here. In fact, my biggest gripe was that it wasn’t obvious that the BreatheSmart comes with app support. While that might be user error – I should have checked the manual – in my view it should have been clearly stated. Luckily, all the necessary functionality is accessible via the capacitive controls.

Easy to set up and use, the BreatheSmart does an excellent job of quickly identifying drops in air quality; an LED indicator changes color to make you aware of the fact. In addition, the unit is fairly efficient at cleaning the air, although you’d be wise to set your expectations according to the filter you have – the basic one will not eliminate all odors, for example.

If you have a very large space, you'll probably get on better with this purifier's bigger brother – read about that one in my Alen BreatheSmart 75i review. Other than that, the only point of contention most people will have with the Alen BreatheSmart 45i is its price. While there are far more expensive options out there, it’s still far from cheap. But, in this humble reviewer’s opinion, it’s worth it.

Alen BreatheSmart 45i review: price & availability

• How much does it cost? Starting at $429 (about £340 / AU$660)
• When is it available? Available now
• Where can you get it? Available in the US

The Alen BreatheSmart 45i is not cheap. The price starts at $429 for the most basic configuration, reviewed here.

Consider upgrading the front panel and this will set you back a further $39. And, if you want to switch out the supplied “Pure” filter to the more powerful “Fresh” filter, that will be another $15; the remaining two filters come in at $30 each. So, you could potentially spend $498 (about £400 / AU$760) for an BreatheSmart 45i with an upgraded panel and filter.

Nevertheless, taking its performance into account, I’d say it’s worth the outlay. Although that cost can be a sticking point when the Blue Pure 411 Auto, for example – one of the highest rated air purifiers here at TechRadar – costs only $140/ £179 (about AU$220).

Note that the Alen BreatheSmart 45i is only available in the US.

• Value score: 4 out of 5

Alen BreatheSmart 45i: specs

Alen BreatheSmart 45i review: design

• Sleek but basic aesthetic
• All functionality available through on-unit controls
• Multiple filters available for different needs

The Alen BreatheSmart 45i is tall, lean, and only slightly boxy. Its design is more discreet than a model such as the space-age Dyson Purifier Hot+Cool Formaldehyde HP09, and while the review model arrived with an all-white exterior, there are five other front panels of various color available to fit your personal aesthetic. Personally, I’m happy with the basic look.

The controls are of the capacitive variety and located on the top of the unit. From here you can turn on the ionizer feature, check and reset filter levels, dim the lights of the controls and the LED indicator (which changes color depending on air quality) that surrounds the power button, set the speed, turn on automatic mode, and lock in current settings so they can’t accidentally be changed.

Basically, you can control every one of the Alen BreatheSmart 45i’s features from this panel. There is an app for both iOS and Android available, which lets you control the Alen BreatheSmart 45i from your couch; but the only added functionality it offers is the ability to track usage and cleaning history.

There are four filters available for the unit. The 'Pure' is the default option – a medical-grade H13 HEPA filter for capturing allergens, dust and mold. 'Fresh' adds in carbon for additionally tackling chemicals and VOCs, cooking odors among other household odors. The 'Odor' filter steps up another gear when it comes to neutralizing odors, while the 'VOC / Smoke' filter comes with extra carbon to absorb noxious gases and secondhand smoke. As such, you should consider your air purifying priorities before you purchase; the 'Pure' filter in the review model does very little to neutralizing smells, for instance.

Alen offers a subscription program that, by default, delivers a new filter every nine months – the natural life cycle of a filter. While the filter can’t be reused, it’s covered in a pre-filter that catches larger particles that can be cleaned.

Lastly, even though the BreatheSmart 45i is among the smaller of Alen’s purifiers, it’s still bulky. However, a handle at the back, near the top of the unit makes it easy to move it around your home. Also welcome is the indent in the base around which you can wrap any excess power cord for a cleaner look.

• Design score: 4.5 out of 5

Alen BreatheSmart 45i: performance

• Easy to assemble
• App support is somewhat hidden
• Powerful filter with good airflow

Before I get into the Alen BreatheSmart 45i’s air purifying performance, let’s discuss setup. On arrival, you’ll find the filter wrapped in plastic, while the front panel has a paper band around it like a freshly cleaned toilet in a high-end hotel. To assemble the unit ready for use, simply pull off the front panel, which is magnetically held into place, attach the filter having removed the plastic, and replace the front panel once you’ve removed the paper band.

The Alen BreatheSmart 45i is WiFi-enabled, but you wouldn’t know just by looking at the unit. As previously mentioned, although you don’t need the app to use the air purifier, access is useful for remote control. To pair the device, start by downloading the app appropriate for your device. Hold one of the capacitive buttons for five seconds until the Wi-Fi symbol lights up and starts blinking. Then, open the app and follow the instructions to connect.

As far as actually using the Alen BreatheSmart 45i, I tested it using copious amounts of incense, a candle, and in a couple of stale-smelling rooms. While it didn’t completely remove strong scents (you’d need the Odor neutralizer filter for that), it did minimize smells.

More importantly, via the LED indicator, it quickly recognized when the air quality had dipped and went into action, cleaning the air fairly efficiently. As long as you don’t use it in too large a space – it’s rated for rooms up to 800 square feet – it can completely clean the air in a room in as little as 30 minutes.

The BreatheSmart 45i has a CADR, or clean air delivery rating of 245. This metric measures the efficiency of the filter and the amount of air that’s pushed through it. While you can have an air purifier with a powerful filter, if it doesn’t push a lot of air through it, it won’t be able to clean the air in your room very quickly.

This air purifier is capable of moving a good amount of air, but in operation, it isn’t the quietest at the higher settings. Our review unit reached 49dB, which is similar to the noise level of the space heater I use. Or, for a more general example, it’s like having soft music constantly playing. It isn’t too intrusive, but it certainly isn’t silent.

Getting back to my real world tests, the BreatheSmart air purifier took about 20 minutes to clear the air of the powerful sandalwood-scented incense once it had stopped burning. With the unit in my home I also discovered that my space heater actually introduces particles into the air every time I use it, with the drop in air quality indicated via the change in color of the LED.

• Performance score: 4.5 out of 5

Should I buy the Alen BreatheSmart 45i?

Buy it if...

Don't buy it if...

Also consider

If our Alen BreatheSmart 45i review has you considering other options, here are two air purifiers to consider...   

Blue Pure 411 Auto
It’s intuitive to use with quiet operation, and it comes at a price that’s easy to swallow. There’s no app or remote control and it’s best used in small rooms, but it will leave those small rooms feeling fresh and clean.

Read our full Blue Pure 411 Auto review

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 arrives with quite a few smart features.

Read our full Dyson Purifier Hot+Cool Formaldehyde HP09 review

How I tested the Alen BreatheSmart 45i

To test the Alen BreatheSmart 45i, I used it for a month to see how it would fare in my bedroom as well as a couple other small to medium-sized rooms in my home. 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 small to medium-sized rooms. However, if odor is a big concern then you’d be wise to upgrade to the appropriate filter.

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 February 2024