Alen

BreatheSmart 45i HEPA

Alen BreatheSmart 45i HEPA

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Overall

#28 in

Air Purifiers

according to Reddit Icon Reddit

Sentiment score88% positive
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Top Pros

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Last updated: May 16, 2026

Reddit Reviews

Reddit IconAint_Folly_4_That
14 days ago

That makes me hopeful! Glad it worked for you! I purchased the Core 600. Next will be Allen 45i. Tganks so much again!

Reddit IconBanyRich
11 months ago

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

11 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
5 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 IconConBroMitch2247
11 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.

5 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.

about 2 months 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.

about 1 month ago

Skip Levoit they’re Amazon junk owned by etekcity and a bunch of other Amazon-only no names. Air doctor is great, so is Alen. IMO Alen is the only actual BIFL purifier because you get a lifetime warranty for as long as you purchase authentic Alen filters (direct or retailers - just keep the receipt). My Alen 45i and 75i are excellent and insanely quiet for the amount of air they move. I highly recommend them.

Reddit IconFairManner1292
about 2 months 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 IconIDontLikeYourToan
15 days ago

Alen Air all the way. Tried just about every purifier sold From Target, Walmart, Kohls, Home Depot, Best Buy, Lowe’s, Menards… Almost all went back Shark used to be good, but their newer filters smelled like chemicals and they were super loud. Germ Guardian was ok, but quality dropped. Dyson is a joke. If you can still find Alen Breathsmart Flex, that’s the best bang for your buck. Locally, you’re more likely to find the 45i. Get one for every room. Check which filter comes with it. You’ll want the one with some charcoal. Surprisingly, the one with less charcoal worked better for VOCs in my experience than the one with. Put one in each room. Maybe 2 in the basement. You said no budget. Remember, if you “don’t like it”, you can always return it. Check the return policies of the store first before purchasing. They throw away the returns, so don’t worry about someone else getting contaminated with your stuff. Maybe a month from now you change your mind and buy it again, from a different store, just to see. Also, when I’ve dealt with VOCs, air purifiers alone were never enough. Get one of those big orange contractor fans and blow it out the windows or screen door whenever you can. It will also help circulate the air for the air purifiers. A less extreme fan option is the Dreo Pedestal fan, which is a pretty good compromise of price and performance, maybe less loud. Also, look for a good deal on activated charcoal they sell for aquariums. Put it in some cheap cloth sacks, place them in the worst spots, and let the fan blow over them, or in a pinch just spread them on a paper plate if you don’t have animals to knock it over. If my wife sees this post, then by now she’ll know it’s me. Hi Bunny! You can probably pick up a lead test swab too if you’re unsure.

Reddit Iconilovefurby333
10 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
5 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.

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