Alen

Alen BreatheSmart 45i

A from Alen, with H13 True HEPA filtration, rated for rooms up to 800 sq ft.

Who this is for:Shoppers looking for a purifier suited to large living rooms and open-plan spaces. If odors, pet smells, or smoke gases are a concern, this model includes activated carbon.

Owners like this air purifier because it keeps dust under control, it clears odors and VOCs, and it's good for pet hair and dander.

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Key specs

New to these numbers? Read What is CADR? and Decibels, translated

Room coverageiThe largest room, in square feet, this purifier can effectively clean — assuming standard 8-foot ceilings and 4–5 air changes per hour.Room size guide →800 sq ft

Noise rangeiDecibels (dB) measure loudness on a scale where every +10 dB sounds roughly twice as loud. 20 dB is a whisper, 40 dB a quiet library, 60 dB normal conversation. For bedrooms, look for under 30 dB on the lowest setting.Noise guide →39–55 dB

Filter lifeiHow long the manufacturer rates the filter to last under normal use. Running in smoky or dusty homes shortens it.Ownership cost guide →12 months

Who the Alen BreatheSmart 45i is for

Specs only matter in context. Here's where the Alen BreatheSmart 45i genuinely fits — and the trade-offs worth knowing before you buy. If you're deciding between this model and similar options, focus on the fit cards below: they highlight the specific use cases where this purifier shines and the situations where it falls short.

Keep in mindAudible in a quiet bedroomIts quietest setting is 39 dB — above the 30 dB most light sleepers need. Fine for living rooms and offices; light sleepers should plan on a hallway spot or a timer.
Good fitOdors, pets, and smokeAn activated carbon stage traps the gases a particle filter can't — cooking smells, litter-box odor, VOCs, and wildfire smoke gases.
Good fitAllergy and asthma householdsA True HEPA filter captures 99.97% of particles at 0.3 microns — pollen, dander, dust mite debris, and most smoke. Run it continuously for real symptom relief.
Good fitSet-and-forget operationListed features include laser smart sensor, auto mode, Alen Air app (V2), LED AQ rings — handy for letting the purifier manage itself, though none of it replaces CADR headroom.
Keep in mindHigh speed reaches 55 dBThat's conversation volume. CADR is measured at max speed, so on quieter settings the effective CADR drops — buy the headroom and run it on medium.
Keep in mindCADR is self-reportedThe Alen BreatheSmart 45i isn't AHAM Verifide, so its CADR and coverage figures come from the manufacturer rather than an independent lab — treat them as a ceiling, not a promise.

What owners say

2 recommendations

Filter by theme

5.0 out of 5 starsr/AirPurifiers
“Complete game changer in air quality in my home.”
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4.0 out of 5 starsr/Pets
“The filters cut down dust and odors.”
Read the thread

Compare with similar models

These alternatives share key traits with the Alen BreatheSmart 45i — same brand family or similar room coverage. Compare their scores, owner sentiment, and specs side by side to see which fits your specific needs better.

Common questions about the Alen BreatheSmart 45i

Quick answers to the questions shoppers most often ask before buying. If your question isn't covered here, check the full specifications below or compare against similar models above.

What size room can the Alen BreatheSmart 45i handle?It's rated for rooms up to 800 sq ft.
Is the Alen BreatheSmart 45i quiet enough for a bedroom?Borderline. Its quietest setting is 39 dB, above the 30 dB target for light sleepers — it suits living rooms and offices better than bedside duty.
Can the Alen BreatheSmart 45i handle odors and smoke?Yes — its activated carbon stage traps odor and VOC gases while the H13 True HEPA filter handles the particles, which is the combination smoke and pet households need.

Full specifications

filter typeiThe particle filter grade. True HEPA captures 99.97% of particles at 0.3 microns; 'HEPA-type' has no standardized efficiency.Filter guide →: H13 True HEPA
model numberiThe manufacturer's exact model identifier — handy when comparing listings across retailers.: BreatheSmart 45i
noise db maxiThe loudest fan setting, in decibels. 60 dB is normal conversation; above that you'll hear it across the room.Noise guide →: 55
noise db miniThe quietest fan setting, in decibels. 20 dB is a whisper, 40 dB a quiet library — for bedrooms, look for under 30 dB here.Noise guide →: 39
smart featuresiExtras like air quality sensors, auto mode, app control, and sleep modes. Nice to have — they don't clean the air themselves.Smart features guide →: laser smart sensor, auto mode, Alen Air app (V2), LED AQ rings
room coverage sqftiThe largest room, in square feet, this purifier can effectively clean — assuming standard 8-foot ceilings and 4–5 air changes per hour.Room size guide →: 800
has activated carboniActivated carbon traps gases, odors, and VOCs that HEPA filters can't catch — essential for smoke, cooking smells, and pet odor.Filter guide →: True
filter lifespan monthsiHow long the manufacturer rates the filter to last under normal use. Running in smoky or dusty homes shortens it.Ownership cost guide →: 12