Alen BreatheSmart 25i Air Purifier Review: Pros & Cons
For anyone keeping track, this is now my fourth Alen air purifier. Needless to say, I love these and truly believe that they make the home healthier. But this newest one, the Alen BreatheSmart 25i, is by far the smallest.
I picked it up to test in a smaller bedroom and to see if the compact size could still deliver the performance I’ve come to expect from Alen. It’s lightweight, quiet, and surprisingly powerful for how little room it takes up. Like the rest of the lineup, it has solid filtration, smart features, and a sleek design, but at a much lower price point.
Alen BreatheSmart 25i Air Purifier: The Verdict
Durability: ⭐⭐⭐⭐☆
Performance & Function: ⭐⭐⭐⭐☆
Price: ⭐⭐⭐⭐⭐
Value: ⭐⭐⭐⭐⭐
Overall: 4.5/5 ⭐⭐⭐⭐☆
The Bottom Line
The Alen BreatheSmart 25i is compact, quiet, and energy-efficient. It’s ideal for small to medium rooms up to 800 square feet and maintains the same reliability and design quality Alen is known for. With whisper-quiet operation, multiple filter options, smart app features, and real-time air quality tracking, it covers nearly everything you’d want, without the premium price tag of the larger 75i.
If you want a dependable, low-maintenance purifier that doesn’t dominate the room or your budget, this one’s a solid pick.
The Alen BreatheSmart 25i
Selling Points
Effective Filtration: The 25i uses Alen’s True HEPA H13 filter (available in Pure, Fresh, or Odor versions), removing 99.99% of particles down to 0.1 microns. It captures allergens, smoke, VOCs, pet dander, and fine dust that often go unnoticed by lesser units.
Compact Power: Despite its small footprint (just 16.8 inches tall), it can clean up to 800 square feet once per hour or 400 square feet twice per hour. Its CADR of 107 means it’s fast enough to noticeably improve air quality in medium spaces.
Quiet Operation: The sound varies between 24–42 dB, which is lower than a typical library.
Smart Monitoring: The built-in AQI display uses color indicators to show real-time air quality, while airID technology detects pollutants automatically and adjusts fan speed to match.
Low Power Use: It runs efficiently at just 24 watts max, so leaving it on around the clock barely dents your electricity bill.
Great warranty. Each purifier that Alen makes comes with a “Forever Guarantee,” however, you need to sign up for the filter subscription service to activate this.
Drawbacks
Smaller Coverage: It’s meant for small to medium rooms. If you’re purifying a large, open floor plan, you’ll want to step up to the Fit50 or 75i.
Warranty. The warranty is only effective if you get the filter subscription.
Wi-Fi Connectivity: While app control is convenient, I personally turn Wi-Fi off after setup due to EMF concerns.
Who Do I Recommend It For?
Anyone with allergies, asthma, or respiratory issues.
Those living in areas prone to wildfires, where the 75i's ability to filter fine particles as small as 0.3 microns is crucial for protecting lung health. Wildfire smoke is comprised of 90% fine particles, also known as PM2.5 (2.5 micrometers in diameter or smaller). A 2021 study found that "Smoke from wildfires is as much as 10 times more hazardous to humans than similar pollution from other sources," such as car exhaust. The 75i filters particles as small as 0.3 microns.which includes these wildfire smoke particles. Read more on this here.
City residents or those in high-pollution regions (check AirNow.gov for local air quality).
Parents of young children with respiratory concerns or a history of RSV and bronchiolitis.
People in apartments or small homes with limited floor space.
Anyone looking to improve sleep, since cleaner air (and gentle pink noise) helps regulate breathing and oxygen levels overnight.
Those who work in an office or room that’s 800 square feet or less.
Health-conscious families wanting a reliable, low-maintenance option without the bulk or cost of a large unit.
Anyone who wants to dust less.
Tips
Don’t connect it to the app. In my opinion, the potential harm of EMF radiation outweighs the benefits of any connection of the unit to your Wi-Fi.
Use Auto Mode and keep the ionizer on for maximum particle removal.
Subscribe for the filter replacements so you don’t forget.
If the space is more than 900 square feet or less then go with the Alen 45i.
Place it away from walls for better airflow.
Specifications/Features
MSRP: $179.99
Coverage Area: Up to 800 sq. ft. (1x/hr) or 400 sq. ft. (2x/hr)
Dimensions: 7.3” x 11” x 16.8”
CADR: 107
Filter Options: Essential (Pure), Advanced (Fresh), Ultimate (Odor)
Fan Speeds: Four
Sound Level: 24–42 dB (whisper-quiet operation)
Max Power: 24 watts
AQI Display: Yes
App Enabled: Yes
airID Technology: Yes
Forever Guarantee: Activated with regular filter replacement
My Experience
What’s nice about these lgiht (and nice looking) purifiers is that they’re so easy to move. When we have guests stay in the guest room (which also has the cat’s litter pan in there) we move one to that room. In the winter time we move them to the first floor when the windows are open less. In the summer time we use them more in the bed rooms.
For the Alen BreatheSmart 25i, we now use it in my son’s room. Within days, I noticed less dust collecting on surfaces and I needed to do less vacuuming in there. The AQI display gave quick feedback whenever we opened windows or ran the vacuum. Seeing the colors shift from yellow to blue after just minutes was satisfying.
Noise-wise, it’s almost silent at the lower settings. On the highest fan speed, it’s audible but not disruptive which now doubles as a white noise machine to help him sleep.
Like other Alen models, the app connectivity is a nice-sounding feature ture but I keep it off most of the time to reduce unnecessary EMF exposure. It’s efficient enough to run overnight without any worry about energy drain or noise.
The Alen BreatheSmart 25i Air Purifier: Is It Worth It?
If you’re looking for an affordable yet high-performing air purifier for small to medium rooms, then yes, it’s worth it. It’s a scaled-down version of Alen’s larger air purifiers in price, size, reach, but not quality.
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