Alen

BreatheSmart 45i HEPA

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Alen BreatheSmart 45i HEPA

Overall

#29 in

Air Purifiers

according to Reddit Icon Reddit

User sentiment91% positive
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Last updated: Apr 6, 2026

Reddit Reviews

Reddit IconBanyRich 1.0
r/AirPurifiersI’m lost
10 months ago

We just bought 3 45i using the bundle deal. One with each filter “Pure, Fresh, and Odor”. We really like them.

r/AirPurifiersI’m lost
10 months ago

We got Odor for the basement with the cat box, Fresh for the one in the kitchen and the regular Pure for the bedroom. I will say they all did come in the “pure” box, but they had the correct filters inside

Reddit Iconclingbat 1.0
r/BuyItForLifeBest air purifier to buy right now?
4 months ago

We use an Alen 75i downstairs in main living space area and two 45i's upstairs, one in the nursery with odor filter that is surprisingly effective and the other in the master bedroom. Not cheap upfront and filters are pricey, but they've worked well for us for about two years now and it's nice to be able to schedule them in app so they don't run at the same time as humidifiers in the winter etc.

Reddit IconComfortable-Plants 1.0
r/CleaningTipsWhat air purifier do you swear by? Trying to cut through the hype.
12 months ago

I have two 45i Alen purifiers (First had an issue that doesn’t really affect usability other than it’s always on high speed and they replaced it for free, without asking for the original back. So I bought another front cover and now have two!) Love them. Filters are replaced about yearly for me.

Reddit IconConBroMitch2247 1.0
r/BuyItForLifeNeed strong air purifier for continuous pesticide exposure+pets (searched other posts I promise)
9 months ago

If you want BIFL the only answer is Alen. They offer a lifetime warranty as long as you buy filters from them or from an authorized 3rd party. The 75i and 45i are excellent depending on your space. I’d get the VOC filter as well.

r/BuyItForLifeThe Best Air Purifier on the Market? Recommendation?
4 months ago

1) Ask r/airpurifiers 2) Alen is really the only true BIFL brand because they offer a lifetime warranty for as long as you buy genuine Alen filters. Plus the filters last a long time too and they are incredibly quiet. Coway and Winix are good too just not at the level Alen is. **Avoid Dyson, blueair and Levoit. They’re junk.** 3) As for sizing, this part is important: most manufacturers advertise crazy sqft numbers (1,000sqft+ for a tiny tabletop unit) just know that most of the time this is disclaimed by stating it can filter all the air in a 1ksqft room ONE TIME per hour. If you actually want to filter your air, industry standard is FOUR times per hour. So in reality, that 1ksqft unit is really only good for a 250sqft room **on full blast** which is usually loud. What kind of space are you trying to purify? An Alen 45i or 75i is great for living rooms and open spaces, then A flex or 25i bedrooms would work well.

r/BuyItForLifeI'd like to know who has a good, reliable air purifier!
12 months ago

Alen is excellent and built like a tank. Also literally BIFL as you get a lifetime warranty as long as you buy filters from them or an authorized 3rd party. Depending on your room size, 45i or 75i are great. (Remember the advertised sqft you see is often 1 air change per hour, if you want it to actually work well, 4 or 4.8 (industry standard) ACH should be used.

r/AirPurifiersAnyone with experience with alen air purifiers.
14 days ago

Love mine. IMO there isn’t any better in that price range especially once you factor in the lifetime warranty. I have the 45i and it’s excellent. I’d lean towards the 45i for your use that way you can run it at a lower setting. I like that you can use an app if you want, but it’s not needed. It can run entirely dumb if you want.

Reddit IconFairManner1292 1.0
r/AirPurifiersAnyone with experience with alen air purifiers.
13 days ago

Agree, have 75i and even on highest speed sound is minimal compared to a whole bunch of others I tried. And even on lower speeds of 3 and 4 still getting 255-300 cfm. I just bought the 45i because I wanted an additional unit in my living space that was smaller footprint. But running on high speed was way louder to me than turbo on the 75i and getting 350-375 cfm vs 255. Should be fine though for a smaller space where you can run on speed 3 vs turbo. In my case, as much as I love how small and lightweight it is, I'm returning. I just ordered 35i for the bedroom as it was a savings over 45i and used a coupon at home depot. Will see. I use the fresh filters.. Love the app, which I didn't think I would even care about. It shows me graphs of when outdoor and indoor levels spike... Co2 , pm2. 5, voc. And I like that I can change speeds and other setting from my phone if needed. I'm assuming the sensor not super accurate, but it shows trends in air quality.

Reddit Iconilovefurby333 1.0
r/moderatelygranolamomsAir Purifier Recommendations?
9 months ago

Alen purifiers. I have 3. They’re amazing, perfect background noise (I’m sensitive to sound), and work really well to the point anyone who stays at my place doesn’t deal with allergies. I own 1 cat for reference and it helps with pet hair thanks to the ionizer option. I have one i75 and two i45s.

Reddit IconJake-rumble 1.0
r/BuyItForLifeThe Best Air Purifier on the Market? Recommendation?
4 months ago

Alen Breathesmarts have been in phenomenal for us. I bought the 45i for living room and a couple 35is for bedrooms. Power, quiet, and auto setting to turn up when particles are detected in the air. They make a huge difference.

Reddit Iconliqwood1 1.0
r/AirPurifiersAnyone with experience with alen air purifiers.
13 days ago

I've had just about every brand of air purifier. I highly recommend Alen air purifiers. I have two 75i's and a 45i. I've had the 75i's for two years now and they have been excellent. The cost of filters is high but that also insures your purchase with the lifetime warranty so hard to go wrong. They are exceptionally quiet even at the highest speed. The only air purifier I've had that is better is the Aeris 3in1 but at twice the cost it's hard to justify when the Alen's work so well. My only advice would be to try and save up and get the larger 75i. They do go on sale about once a year for pretty deep discount.

Reddit IconNeuro_Wiz 1.0
r/BuyItForLifeBest air purifier right now for smoke?
about 1 month ago

There is more to smoke removal than just a filter, with it comes gases/voc's/odors. Having a purifier with carbon would help beyond the standard filtration I think the top rated purifier for smoke is probably something like the IQAir offerings, however they are well above the budget you listed. The Alen 45i is probably right behind it, and you may be able to find one used or on sale at the top end of your budget. Within the range you posted, I would look at the Levoit Core 600S. It is consistently one of the top rated in its price range, for air changes/CFM, and it also boasts nearly a pound of Carbon for odor and VOC removal. Note this will not be as effective as a purifier meant for VOC's, but those are very expensive

Reddit IconNexter1 1.0
r/AskNYCBest air purifier for NYC apartment?
9 months ago

I use Alen air purifiers in my apartment. It’s made a huge difference. I’ve wanted to become a “windows shut” apartment for a while, but whenever I would try it, I always found the apartment getting too stuffy. Now though after I put two Alen 45i units on opposite sides of my (large) living room/dining area, and one in the bedroom, the air now feels breathable and not at all stuffy when all the windows are closed. I got the VOC filters, though as others have said, that will only do so much. It’s definitely satisfying though when I start cooking and all of the air quality indicators go red on each of the units, but then they kick into high gear and within like 10 minutes the air quality starts to improve quickly, even when still cooking.