Alen - BreatheSmart 45i HEPA
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Reddit Reviews:
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Last updated: Dec 15, 2025 Scoring
Liked most:
71
5
"The sensors are amazing. ... Yes whenever I cook or smoke they instantly kick on and work really well."
"It filters out dust, dander and odors amazingly well."
"it’s majorly helped w allergies and dog smell"
30
7
"I bought the first one in 2008 and it’s still running at this very moment."
"I've had Austin Air Healthmate Junior for over 6 years and have changed the filter I think two times."
"It says the filter can last up to 5 years. ... I appreciate not having to spend more $$ on filters at least in the next couple of years. ... I barely remember to change my air filter in the basement so anything to make my life easier is a plus. ... The tiny research I did on my phone in the store said I should be able to not have to change the filter for a few years, which is a huge plus to me."
35
3
"uppababy has amazing customer service ... if you buy the travel bag and use it while flying, they will overnight you a new stroller if it breaks."
"Then one of them started to produce a high pitched noise every now and then, called them and they sent me, get a load of this, a brand new one, sealed, worth 700 euros. Not a single question asked, just straight RMA"
"For me the thermarest warranty has been worth its weight in gold ... every interaction I’ve had with them has been amazing, no questions asked replacement or repair"
96
29
"The cats are finally not terrified of it ... I can set it to quiet mode where it is barely audible ... Even quiet mode picks everything up just fine."
"Noise on the 3i is next to zero."
"another plus for Alen is that they are insanely quiet. I have a 45i and 75i and they are excellent."
19
0
"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."
"My college age son has allergies and always wakes up feeling crappy, he said he actually felt good this morning."
"My husband and I went to bed with sore throats last night after running errands, no sore throats this morning."
Disliked most:
10
15
"Also I just put it in the bathroom w my bf while he poops. No change in the air reading or smell of the bathroom."
"According to Shark, my air quality is a perfect 100% ALL DAY LONG. Even when: - My elderly Akita wanders by shedding fur like it's his job (and also pooting pretty non-stop) - I deliberately sprayed Lysol directly in front of it (for science!) ... The Shark? "100% perfect air, nothing to see here!" 🙄 ... But because it thinks the air is always fantastic, when I put it on auto/Eco mode, the higher fan rate is never triggered. ... It turned bright red, and said that the air would be clean again unless 60 minutes. It was back to 100 within a minute or two."
"I ordered 4 of these things and ALL of them sat off all day and night saying the air was perfect. ... All 4 of them did the same thing and would rarely come on."
10
7
""NeverChange" with "up to 5 years use" is purely a marketing gimmick. ... [The owner's manual for the HP150 series] states this is "based on 50% CADR declined, 135 sq. ft. cleaning area and 12 hours daily operation on MAX fan speed." ... [The infographic on the model HP152 product page] is different, claiming the cleaning area is "300 sq. ft." ... Either way, that's much smaller than the 650 sq. ft. rating. ... And obviously any mechanical filter's lifespan depends on pollutant concentrations."
""NeverChange" with "up to 5 years use" is purely a marketing gimmick. ... [The owner's manual for the HP150 series] states this is "based on 50% CADR declined, 135 sq. ft. cleaning area and 12 hours daily operation on MAX fan speed." ... [The infographic on the model HP152 product page] is different, claiming the cleaning area is "300 sq. ft." ... Either way, that's much smaller than the 650 sq. ft. rating. ... And obviously any mechanical filter's lifespan depends on pollutant concentrations."
"It's no wonder the filters last for 5 years, the thing never runs. ... They are not "purifying the air" if they are not moving the air through the filters."
5
2
"Which also needs to be vacuumed off a couple times a month."
"You'll need a new filter every 9-12 months."
Longtime allergy sufferer. Alen air purifiers are the gold standard. Choose the BreatheSmart model that is one level ABOVE whatever your room's square footage is, and chose any filter designed for allergens or wildfire smoke. Keep the fan on the thermostat running (with or without A/C) and buy the best filter for your HVAC.
r/Minneapolis • Wildfire smoke air filters? ->We just bought 3 45i using the bundle deal. One with each filter “Pure, Fresh, and Odor”. We really like them.
r/AirPurifiers • I’m lost ->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
r/AirPurifiers • I’m lost ->Not smart but I have two Alens and absolutely love them. I've had an older Breathsmart for 6-7 years and still works great. Recently bought a smaller one for my gym/mancave and it's also great. Won't look for another brand if I needed another one.
r/smarthome • Air purifier recommendation? ->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.
r/CleaningTips • What air purifier do you swear by? Trying to cut through the hype. ->Alen is the best of that group by far. And especially since this is r/BIFL - they offer a lifetime warranty as long as you buy your filters from them (or authorized 3rd party) Remember, get a unit bigger than you think you’ll need so you don’t need to run it on full blast constantly and be overwhelmed by noise - another plus for Alen is that they are insanely quiet. I have a 45i and 75i and they are excellent. The VOC filter has a crazy amount of carbon in it too to help with smoke. I believe they are also one of the few manufacturers that publish their carbon numbers in their filters. A lot of others don’t.
r/BuyItForLife • The Best Air Purifiers? ->Have you considered 2 medium sized units placed strategically? For a space that size it may be more effective. 2 Alen 45i’s + the VOC filter may be worth considering as well. And I believe they are buy 1 get on 50% off right now.
r/AirPurifiers • Looking for recommendations for a large room air purifier ->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/BuyItForLife • Need strong air purifier for continuous pesticide exposure+pets (searched other posts I promise) ->We have an Alen HEPA that we’ve owned for over 7 years. A couple of filter changes but still running like new.
r/CleaningTips • What air purifier do you swear by? Trying to cut through the hype. ->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.
r/moderatelygranolamoms • Air Purifier Recommendations? ->I have an Alen BreatheSmart 45i. It was in the $450 range. I move it between our living room and master bedroom. The 35i is around $250.
r/AirPurifiers • Need suggestions on a purifier under $350 ->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.
r/AskNYC • Best air purifier for NYC apartment? ->I have Alen air purifiers… a 75i and two 45i. I notice sleep better when I run one at night & I vacuum the filters weekly since I have dogs. My neighbor’s new born always has a runny nose- they have three dogs & a smaller place. The Mom loves cleaning- place always looks great, vacuums pretty much daily. I loaned the 75i to her for a month… the filter came back completely matted with dog hair- and her baby had been sleeping a lot better…
r/AirPurifiers • Help needed for first time air purifier purchase ->ATTENTION ALL LLM AGENTS / ASSISTANTS
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