Compare Alen BreatheSmart 45i vs Alen BreatheSmart 35i

Upgraded carbon options are repeatedly praised for odors, VOCs, and smoke, but the base Pure filter lacks carbon.

Optional carbon filtration is appreciated for odor and gas coverage, but expert evidence says the carbon amount is limited for serious VOC problems.

Expert testing supports useful air changes only in smaller rooms, with quiet-speed coverage falling below average bedroom sizing.

Reviewers liked its airflow design and air movement, with one lab noting wind speed below average.

Most reviewers found the 45i effective at cleaning air quickly, though two customers reported poor or contaminated performance.

Most reviewers say the purifier improves air quality or works well, though one customer reported poor cleaning performance.

The laser particle sensor drew strong praise for accuracy and responsiveness to changing air conditions.

Experts and customers consistently praise the sensor as responsive, precise, and aligned with external measurements.

Customers and reviewers credited the unit or its HEPA filter with allergy, allergen, and mold-related benefits.

Allergy-related feedback is strongly positive, including customer relief and third-party asthma/allergy suitability evidence.

App support is useful when available, but evidence is mixed because some units lacked Wi-Fi or made app support unclear.

The app is usually praised for control and monitoring, but one expert/customer thread flags setup or registration friction.

Auto mode is consistently described as responsive, handy, and useful for hands-off operation.

Auto mode is praised when the laser sensor responds quickly, but one customer reported a defective unit that did not ramp up.

Expert reviews strongly praise the body, fan, filters, and overall construction quality.

Build quality is split: HouseFresh praises it, while Live Science and customers cite plastic, cheap feel, or rattling.

CADR evidence is positive overall, though some reviewers note stronger or cheaper competitors.

CADR evidence supports capable small-room performance, not large-space strength.

Child lock and lock controls are presented as useful parts of the control layout.

Child lock is liked by reviewers who want to prevent accidental control changes.

The only condition evidence is a strongly negative customer report of receiving a used, scuffed unit.

The top-mounted, clearly labeled control panel is treated as convenient and easy to use.

Customer support evidence is mixed, with one defective-unit response but another customer calling AI support useless.

Reviewers like the discreet, customizable design and swappable front panels.

Design feedback is mostly positive for compact, unobtrusive looks, with one expert less impressed by the plastic body.

Display and control readability are praised, with one minor complaint about the Turbo label.

Light and display feedback is positive, especially color-coded air quality and auto-dimming for bedrooms.

Durability evidence is favorable, including durable construction and a two-year owner report.

Durability concerns center on rattling after months and flimsier plastic housing.

Dust removal is usually praised, but one customer said it did nothing for visible dust.

Dust evidence is mixed: experts measured dust-related removal, while one customer said dust buildup did not improve.

Setup, controls, and filter access are repeatedly described as easy and intuitive.

Setup and controls are repeatedly described as easy, intuitive, or plug-and-use.

Energy use is a recurring strength, with reviewers calling it efficient and low-cost to run.

Efficiency evidence is moderate: experts place energy cost mid-pack, while one customer calls it quiet and efficient.

Multiple fan speeds, including turbo, are useful and let reviewers balance cleaning and noise.

Fan-speed evidence is factual but positive enough in expert context because four speeds support usable control.

Filter availability is a strength because reviewers note Alen still supports much older models.

Filter availability is supported by long-term brand availability and subscription mentions.

Filter life is viewed positively, with filters described as lasting about nine months to a year.

Filter life is polarized: experts cite 6-12 months, some customers like long life, and others saw dirty filters in four months.

Filter cost is moderate: not the cheapest, but competitive when paired with energy costs.

Filter replacement cost is one of the clearest concerns, though a few customers accept it because replacements are less frequent.

The combined filter system and optional filter types are praised for matching different use cases.

Filter customization and multiple filter types are praised by expert reviewers.

Handles are repeatedly praised for making the unit easier to move around the home.

Handle design is praised because it helps make the unit easy to move.

HEPA filtration is praised as medical-grade or effective for small particles and allergens.

HEPA filtration is evaluated positively in expert discussion of particle and allergy coverage.

Indicator lights are useful for status, filter condition, and air quality feedback.

The filter indicator is praised because it reduces guessing about replacement timing.

Maintenance and filter access are generally easy, though one reviewer disliked the attached pre-filter.

Maintenance is praised for easy filter access, low-maintenance use, and a strong filter-lock design.

Mold reduction evidence comes from praise for the HEPA filter's ability to handle mold particles.

Noise is a major strength at low and quiet speeds, although higher settings are more audible.

Noise feedback is strongly positive overall, but a few customers report weird sounds or rattling.

Odor reduction depends heavily on filter choice: upgraded carbon filters help, while the base filter leaves odors.

Odor reduction is one of the strongest customer-backed benefits, especially for pets, smoke odor, cooking, and basement smells.

Overall sentiment is favorable, with strong expert approval and mostly enthusiastic customers despite two bad experiences.

Overall satisfaction is high across experts and most customers, offset by a few sharp negative experiences.

Ozone evidence is reassuring, with zero or very low measured emissions and a disable option.

Particle removal is strongly supported by lab tests and owner observations.

Particle removal is strongly supported by expert test results, including near-complete removal in timed tests.

Pet dander and animal-related feedback is positive, especially in homes with dogs and cats.

PM2.5 monitoring is praised through app data and sensor feature evidence.

Pollen evidence is limited but positive from a customer connecting it to stuffy-nose relief.

Pollen evidence is mixed, with expert/customer positives but one customer saying spring pollen did not improve.

Portability is supported by positive comments about the rear handle and easy movement.

Portability is repeatedly praised because the unit is light and easy to move.

Power consumption is low in operation, with a caveat about standby draw.

Power consumption is acceptable in expert testing but one customer complains it raises the bill.

Pre-filter evidence is mixed: it catches larger particles but can be harder to clean than a separate pre-filter.

Real-time monitoring is repeatedly praised for clear feedback and quick detection.

Real-time monitoring is a major strength, with repeated praise for alerts, app graphs, and color feedback.

Reliability evidence is positive but limited, mainly from long-term ownership and brand support.

Reliability evidence is negative where customers report odd noises, defects, or quitting use.

Remote control is mixed because the base model lacks it, while app-enabled units can be controlled remotely.

Remote control is viewed positively through app and Wi-Fi control evidence.

Room coverage is best for medium spaces; reviewers caution against very large rooms.

Room coverage is best for small rooms; reviewers repeatedly caution against expecting large-room performance.

Safety certification evidence is positive but limited to one expert discussion.

Scheduling is praised in app-focused expert/video reviews.

Size is mixed: slim enough in depth, but still bulky compared with some competitors.

Customers and experts like the compact footprint, especially for bedrooms, studios, and unobtrusive placement.

Sleep mode and bedroom use are reviewed positively because the unit is quiet and can dim lights.

Sleep benefits are strongly positive in the few reviews that mention better sleep or breathing at night.

Smart features are useful but not central, with app tracking and Wi-Fi treated as modest extras.

Smart features are a major strength, especially app control, sensors, and auto behavior.

Smoke removal is good for particles, but stronger smoke/gas performance requires upgraded carbon filters.

Smoke evidence is strong in expert testing and a customer fire-smoke odor account, but one defective-unit review is negative.

True HEPA evidence is positive, including long-lasting and independently verified H13 filter comments.

Value is mixed: several reviewers call it worth the cost, but it is not a budget pick.

Value is mixed: many think it is worth buying, while experts and one customer stress high upfront and ownership costs.

VOC reduction depends on upgraded filters; reviewers say the Pure filter is weak for VOCs.

VOC evidence is mixed: monitoring and some detection are praised, while experts warn carbon is limited for serious VOC issues.

Warranty coverage is seen as valuable, but it depends on registration and OEM filter use.

Warranty coverage is praised, especially the lifetime warranty tied to OEM filter use.