Ratings & Reviews for Alen B4-Fresh + Carbon HEPA Air Purifier Filter

Works great

Does a great job filtering my air. New apartment and I was congested and sneezing but once I got this going I felt a whole lot better

Excellent for pets

I have 2 dogs and it really helps with their coat and my allergies.

The only one I'll buy! Home smells cleaner!

Catches More than Dust

Breathing comfortably

Im loving this wonderful product Alen Breathe Smart Hepa Air purifier. . I sleep so good at night and if my RV gets warm from not running my air conditioner this unit is remarkable at cooling off my space with kitty. . I highly recommend…I have the subscription to get another filter, its here, this unit is very quiet.

Solid Build and Clean Air

This filter fits perfectly and noticeably reduced the dust in my living room within days. It feels much higher quality than standard filters and doesn't restrict airflow at all.

Air filter

Exactly what I needed for my Alen air filter

B4- Carbon HEPA Air Filter

This filter combined with the ALEN BreatheSmart 45i HEPA Air Purifier makes breathing in clean air a necessity and fundamental.

It works beautifully

I have really severe allergies and multiple chemical sensitivity and this filter has been working really well. Yesterday I was having really severe asthma and I couldn't figure out why and then dawned on me I had forgotten to turn it on. Trey pollen is extremely high right now and something I react to. Within 15 minutes of turning the filter on I was breathing much much better. It does a great job removing cooking odors and other things too!

Alen Stopped Making the Smoke/VOC Filter

I bought the 45i purifier because of the Smoke/VOC filter that was available at the time. With my most recent subscription purchase, instead of sending me the Smoke/VOC filter, they sent a Fresh filter. No explanation was provided. It turns out that they stopped making the Smoke/VOC filter for the 45i. The Fresh filter is inferior in performance.

Great for pet allergies

Had an allergic reaction to one of my cats that was so bad that my lungs would burn. The Alen resolved this issue pronto !

Amazing

We have had 3 purifiers since COVID. This 45 I in our bedroom is amazing and so much different from cheaper past units. We have ordered A 75i for living room.

Its great, but you filter choice is VERY important

I've had mine since May 2025 and I can honestly say that it does what it suppose to do but your filter choice is VERY important! The only reason i gave it 3 and not a 4 or 5 stars is because it doesnt pick up as much dust in the air than i thought it would. I thought the fresh would be in the middle of collecting dust and smoke/odors. It definitely works for odors, but hardly for dust. My room is about 150sqft and i place it where it has enough space for air flow and collect dust and odors. All ...

NEW 45i Filter a real Disappointment!

Me, too! The NEW 45i filter design is a REAL DISAPPOINTMENT!! I happily would change out the older filter pre-filters monthly-showing everyone how much dust and hair was trapped on them. They worked great! PLEASE, PLEASE go back to your former design with the velcro attached pre-filter!

New design is too noisy

I used to love my Alen . . . until they came up with this new filter. The major reason I went with Alen is that they considered the noise factor in their design. The old, thick carbon pre-filter was MUCH quieter/less annoying than what they've done now, which is like a thin sheet of mesh. I have bad allergies (MCAS) and now I can't run the machine at the speed I need to without the noise driving me insane. Let's be real, times are tough and these things aren't cheap. I was willing to shell out s...

Bought a second Alen for the basement!

I love my second Alen. As I have a mold problem, I replaced the filter in the 45i in my living space with a VOC filter. It worked so well, I decided to get a second 45i with a VOC filter for the basement where the mold originates from. Cleared the air amazingly well! And in doing so, reduced the mold smell coming up into the house! Go Alen!

Great Quality and Odor Control.

Our family has confidence in our air knowing that Alen is working. We have a lot of pets and we have noticed a tremendous difference in smells/pet odor. Thank you!

New filter design is TERRIBLE

I have a large home with four dogs. I have six Alen units in my home! They work well. HOWEVER…. . the new design where you can no longer change the pre filter is horrible. It was clearly done to make customers have to buy more filters. I’m really disappointed in Alen for this.