Alen BreatheSmart 35i Air Purifier: Trusted Review & Specs

This svelte compact air purifier Alen BreatheSmart 35i has curves and smart features in all of the right places and offers up a solid air-cleaning experience. Issues with its low fan power prevents it from being an instant recommendation however, so let’s read the Alen BreatheSmart 35i review to decide whether you want it or not.

Alen BreatheSmart 35i ranks A in our air purifier ranking list. We give the biggest and most thorough database of air purifier reviews in the world.

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Alen completes the current “i” generation, marking a real step up from the past: AI particle sensors, True HEPA filter and Wi-Fi capability. The Alen BreatheSmart 35i the first air purifier to introduce these upgrades for a cheaper price, and the new Alen BreatheSmart 25i is even more affordable. But today, we will only talk about the Alen BreatheSmart 35i review.

Other Alen’s Air Purifier Reviews:

Alen BreatheSmart 35i Price

The Alen BreatheSmart 35i is the newest entry in the veteran manufacturer’s smart air purifier line, coming in at $299, though Alen’s own storefront is selling the unit in a buy-one-get-one-half-off bundle currently.

This air purifier is a choice for people who want something between the Alen BreatheSmart 25i and the Alen BreatheSmart 45i. For the price you’re paying, short of hitting up the likes of the Coway Airmega 350, Blue Signature SP3i, Blue Pure 211i Max and Levoit Core 600S. They all offer stronger performance while providing the same smart features as the Alen BreatheSmart 35i.

Still, if you’re a fan of Alen, the Alen BreatheSmart 35i remains a solid choice with a respectable ranking. If you decide to buy it, be sure to check our latest deal, where you can often find the Alen BreatheSmart 35i for as low as $219.

Related post: Best air purifier 2026.

Alen BreatheSmart 35i Design and Size

Typically, buying an air purifier from Alen implies that you love this design, because the same design shares from the very first Alen BreatheSmart into this current line. Those taking the plunge can usually expect the typical console air purifier with a front-to-top airflow system concept, hiding beneath the front panel.

Against this, the Alen BreatheSmart 35i doesn’t quite come across as a device really trying to make a difference, and it is just the simple console air purifier that does its job. There is still a minor difference, as the Alen BreatheSmart 35i uses two narrow raised legs, rather than the usual flat base from the Alen BreatheSmart 45i.

The only stab at style is the new control panel, complete with a new Wi-Fi button and several layout changes. This is also the new update for the version 2 of the Alen BreatheSmart 75i and 45i. Behind the control panel, you can find the usual air outlet.

The Alen BreatheSmart 35i sits in the middle of the lineup in terms of size, measuring 13″ W × 7.6″ D × 20.3″ H. It is compact enough to fit comfortably in smaller homes or rooms. If you need an even smaller air purifier, the Alen BreatheSmart 25i is a better option. The Alen BreatheSmart 35i weighs 11 lbs and includes a built-in handle, making it easy to carry from room to room.

Related post: Best air purifier for bedroom.

Alen BreatheSmart 35i Filters

As the decisive criteria for the performance of one air purifier, by default we look at the quantity and the quality of its air filters, and what the air filter types are using. The Alen BreatheSmart 35i uses only using 1 filter for its air filtration system.

1. H13 True HEPA filter – The Alen BreatheSmart 35i captures 99.9% of particles as small as 0.1 microns, including bacteria, aerosolized viruses, allergens, dust, pollen, and mold spores. Choose from 3 specialized configurations:
   • Pure – The standard True HEPA filter for everyday allergens, dust, and mold.
   • Fresh – Adds an Activated Carbon filter for households sensitive to VOCs, cooking odors, and chemicals.
   • Odor – Uses Alen’s patented Molecular Conversion Powder instead of standard carbon to destroy heavy pet odors at a molecular level, rather than simply absorbing them.

It uses the same customizable filter concept introduced with the original Alen BreatheSmart Classic, and Alen continues that approach with the Alen BreatheSmart 35i. In the past, these air purifiers used a HEPA-type filter, but the current Alen lineup has been upgraded to an H13 True HEPA filter, delivering a significant improvement in filtration efficiency and overall performance.

However, with its low fan power, the Alen BreatheSmart 35i struggles in the test supposed for an air purifier in this price point. As you can see, the result of the Alen BreatheSmart 35i is only 97.65% after 1 hour, which is worse than the Medify MA-50 v3.0, Coway AP-1512HHS and even the LG PuriCare AS401VSA0 that costs a bit higher.

For the cost of the base Pure air filter of the Alen BreatheSmart 35i, it is $54, so $15 more affordable than the Alen BreatheSmart 45i, and it lasts for 1 year.

Related post: Best air purifier for allergies.

Alen BreatheSmart 35i Room Coverage

For the best performance, you should use the Alen BreatheSmart 35i in a room of around 233 square feet. At the manufacturer’s claimed coverage of 500 square feet, the air purifier will provide about two air changes per hour.

The ACH of the Alen BreatheSmart 35i is 5X. In our suggested room size, the air purifier will clean your space every 12 minutes.

The CADR of the Alen BreatheSmart 35i is 164 Dust/ 150 Smoke/ 195 Pollen (cfm). The performance is easily bested by a half-the-price Winix 5510.

Related post: Best large room air purifier.

Alen BreatheSmart 35i Sound

In day-to-day use, beyond waiting a little longer for large-room clearance, we have an air purifier that is fairly quiet at only 23 decibels (dB). It is resting just above the threshold of a human whisper, like a ticking clock heard from a few feet away.

Even on its highest speed, the noise level of the Alen BreatheSmart 35i is around 42 decibels, which is very quiet for an air purifier. It is just like the noise of a library, if you wonder.

Related post: Best air purifier for baby.

Alen BreatheSmart 35i Power Consumption

One of our most FAQs is “Do air purifiers use a lot of energy?” An air purifier is meant to run for a long time to be efficient, that’s why many air purifier brands consider the energy-saving standard, mostly in the rate of Energy Star, is one important selling point.

The Alen BreatheSmart 35i is an Energy Star air purifier, with a very impressive performance per watt. Its rated power is only 23 watts.

If you’re going to use the Alen BreatheSmart 25i at least 8 hours per day, the annual energy cost is just $10.

Related post: Best air purifier for pets.

Alen BreatheSmart 35i Additional Features

With RFID smart filters and a power-sipping motor, we came with great expectations for the running costs and day-to-day experience of the Alen BreatheSmart 35i. And for the most part, the Alen BreatheSmart 35i delivers.

The airID sensor sits at the heart of the smart feature set. Using AI-powered optical technology, it detects, identifies, and measures airborne particles in real time – distinguishing between dander, smoke, pollen, and smog rather than just returning a single particle count. The color-coded ring translates that data into a five-state visual indicator that updates continuously, which makes checking air quality genuinely intuitive without opening the app at all.

The Alen Air app extends that visibility to your phone, surfacing real-time PM2.5 and VOC readings, filter lifespan tracking, and scheduling controls. Multi-unit management is supported, so users running a second Alen unit in a bedroom can monitor both from a single screen.

Finally, we have Child lock setting and a LED indicator for filter replacement.

Related posts:

1, Best air purifier for smoke.

2, Best air purifier for dust.

3, Best air purifier for mold.

Alen BreatheSmart 35i Customer Service

Running through a very long review about Alen air purifiers, you may question us: “Why I need to buy Alen air purifier?” Yes, if it is not for the outstanding performance, or the top-class fan power, then there is must be something really, really important. What I’m trying to say here is the perfect customer service from the Alen Corporation.

Alen doesn’t hide the intent to speak high of their customer services. Look at their website, there are full of content to support the customers. You will have their phone, their emails, and of course, their support policies without any hindrance. To reach the Alen, you can contact them 6/7 days per week. They provide the best fast and free shipping for any products, as long as the orders are placed before 3 PM, they will guarantee to ship in the same day. Impressive, right?

They expand the refund time up to 60 days, or 2 months. You won’t need to worry about the quality of your air purifiers, because Alen will back you up with 3-year warranty (not Forever Guarantee anymore). Whenever your personal Alen air purifier doesn’t operate as normal in the third year, you will have a same refurbished air purifier with free shipping. To do this, please call 512-436-0457.

There are a lot of good reviews for the Alen customer services, that’s why I highly recommend to look for the brand if you need better air quality for your home.

Our verdict

The Alen BreatheSmart 35i proves one thing: an air purifier doesn’t need top-tier performance to find its audience. Instead, Alen has focused on low energy consumption, quiet operation, and a full suite of smart features. As a result, the company can still offer a compelling product despite its modest performance. The same philosophy also applies to the Alen BreatheSmart 25i.