This Sleek Air Purifier Is Designed for Small Spaces — And It’s the Best I’ve Ever Tried

Once you start to think about how much dust, dander, and other microscopic debris is constantly floating around your room, it’s hard to get it off your mind. That’s where an air purifier comes in: It’s designed to suck those things in and filter them out, resulting in cleaner air that has the potential to reduce allergy symptoms, make your space smell better, and even help you breathe more easily. Especially when you’re living in a small space, like a dorm or apartment, you want to make sure you’re keeping your surroundings clean — and that includes the air around you. 

Between New York’s intensely bad allergy season this year and my cat’s gorgeous but ever-shedding fur, I decided it was time to bring a new air purifier into my apartment. So when Alen offered to give me their BreatheSmart 25i air purifier so I could test it out, I immediately said yes. After a couple of months of testing, here’s my honest review.

The BreatheSmart 25i is Alen’s smallest air purifier, both in terms of how much space it takes up and how much air it’s designed to clean. It measures about 17 inches high, 11 inches wide, and 7 inches deep, and purifies 800 square feet every hour or 400 square feet every 30 minutes. In contrast, the largest model, the BreatheSmart 75i, measures 27 inches high, 18.5 inches wide, and 11.5 inches deep, and covers 1,400 to 2,800 square feet. 

The BreatheSmart 25i air purifier uses a medical-grade HEPA filter “that captures 99.9% of airborne dust, viruses, and allergens,” according to the product description. The unit comes with a filter, but when you need to buy a replacement, it costs $44 for the Essential version (and goes up to $54 depending on the filtration grade you choose — there’s also Advanced and Ultimate). If you run the purifier 24/7, as is recommended, the Essential filter is intended to last 9 to 12 months, so you’ll probably only need to dish out that money every year or so.

At $179, the BreatheSmart 25i isn’t the cheapest air purifier on the market, but, like all of Alen’s products, it comes with a “forever guarantee,” meaning that if you have an issue with your unit that isn’t fixed after troubleshooting, they’ll send you a replacement. 

• Alen’s smallest air purifier
• 17 inches high, 11 inches wide, and 7 inches deep
• Purifies 800 square feet every hour or 400 square feet every 30 minutes
• Uses a medical-grade HEPA filter 

From the setup to the size, here’s what I love about this air purifier. 

When I first unboxed the BreatheSmart 25i air purifier, I wasn’t particularly struck by its aesthetic — and for me, that was perfect. It’s a small, shiny white box with a band of black that wraps around the middle, and a light-up display touch-button on the top. There are air purifiers designed to be stylish on their own, and even chic purifier-lamp hybrids, but this just looks like a sleek, simple unit that you can easily tuck away without it clashing with your decor. I put mine in a little recess in my hallway, where I all but forget it exists.

It took literally two minutes to set up this air purifier. After taking it out of the box, I removed the front cover, inserted the air filter it came with, replaced the cover, and tapped the “on” button. I also downloaded the Alen Air app, and connected it to my purifier, which was simple; the app walked me through it, and it just involved entering my WiFi password and pressing a button on the unit to enable pairing. Honestly, I don’t often love the apps that home appliances come with, but I’ve found this one really useful — more on that later!

The small rectangular box that is the BreatheSmart 25i only weighs 8 pounds, so it’s easy to pick up and move around. I prefer to leave mine neatly tucked away in my hallway nook, though, as it’s designed to clean a space as large as my entire apartment. It’s perfect for anyone living in a studio, one-bedroom apartment, dorm room, or anywhere in the 400- to 800-square-foot range. 

After a couple of months of using this air purifier every day (seriously, I haven’t turned it off), I am a fan. Here’s why.

I own another air purifier that I use at the opposite end of my apartment, but unlike my Alen unit, I only turn that one on occasionally because it’s so noisy. My other one would certainly make for a powerful white noise machine if you’re looking for one to lull you to sleep, but if you want something so quiet you forget it’s on, I can’t recommend the BreatheSmart 25i enough. 

A few days after installing my BreatheSmart 25i air purifier, I spent a day doing a deep clean of my apartment. I used lots of Lysol, tub cleaner, and air freshening spray (which I don’t typically use). Looking at my app later, I noticed that while most of my air quality categories were in the “ideal” or “excellent” range, the “TVOC” category was marked as “fair” quality. TVOC stands for Total Volatile Organic Compounds, and is essentially a measure of air pollution. When I did some more research, I learned that household cleaners and aerosol sprays are sources of VOCs, so it made complete sense that my levels were elevated shortly after sanitizing my home within an inch of its life. 

Magically, though, when I checked the app a couple of days later, the level had gone back to ideal. It felt good knowing that the air purifier was ridding my apartment air of potentially toxic particles without my having to do anything besides let it run. 

About a week after I connected the purifier, there was a small hiccup: I got a “clean filter” alert, although I knew it couldn’t be time to replace it yet, as the filter is intended to last up to 12 months. After turning off the unit, removing the filter, and replacing it, per Alen’s instructions, the alert went away and I haven’t had any issues with the app since. 

If you live in a dorm or an apartment that’s 800 square feet or smaller, the Alen BreatheSmart 25i Air Purifier would be an excellent addition to your space — especially if you struggle with allergies or asthma, use a lot of cleaning products or air fresheners, or generally feel like your air could use some cleaning (hello, dorm living!). The sleek silhouette helps this unit blend in with most aesthetics, so you can enjoy an air purifier without feeling like you have to decorate around it.

If you want to buy one for your space, now is a great time: the Alen BreatheSmart 25i Air Purifier will be 10% off from May 20-29 as part of Alen’s annual sale.

Buy: Alen BreatheSmart 25i Air Purifier, $179