Compare Shark NeverChange Max vs Alen BreatheSmart 75i

Reviewers treat the carbon layer as part of the odor and gas-control system, but one clinical-style review says VOC filtration is not this model's strength.

Carbon-filter evidence is positive for odor/VOC-focused filters but one customer complained about dusty carbon filters.

Opinionated evidence was found for this attribute in the listed reviews.

Airflow is strong enough for large-room cleaning, though one video reviewer wanted more swirling circulation instead of mostly upward airflow.

Air circulation is praised for strong movement and mixing, though one reviewer questioned full-room coverage for viruses.

Reviewers mention this attribute in concrete use, with experiences varying by room conditions and expectations.

Most reviewers say the Shark noticeably cleans rooms, improves air quality readings, and makes stale or polluted spaces feel fresher. A smaller group report defective units or doubt that their air was actually being cleaned.

Most reviews report strong air-cleaning performance, though a minority of customers saw little benefit or defects.

The sensor often reacts quickly to cooking, smoke, candles, and vaping, which gives owners confidence Auto mode is doing something. A few units stayed at 100% or threw red-ring errors, making sensor behavior a recurring caveat.

Sensor feedback is often seen as quick and helpful, but humidity and mold complaints raise accuracy concerns.

Allergy-focused owners often mention easier breathing, fewer symptoms, and better comfort around dust, pollen, pets, or construction debris.

Allergy/asthma relief is a strong customer theme, with many reports of easier breathing and better mornings.

Several reviewers note the lack of app or Wi-Fi control, and one buyer specifically wished Shark had made this model smarter.

App control is useful for remote access and data, but feedback is mixed on discoverability, intuitiveness, and connection reliability.

The scent cartridge is polarizing: some like the added freshness, while others find it weak, too artificial, or clinically undesirable for sensitive users.

Auto mode is one of the most praised features because it ramps up when the air gets dirty and settles back down after the room clears.

Auto mode is commonly praised as set-and-forget, though some users found it too sensitive or aggressive.

People with congestion, asthma, allergies, smoke exposure, or stuffy homes often describe easier breathing after using it.

Experts generally call the build solid and well executed, though one notes the plastic intake guards could be vulnerable to cracks.

Build quality is mostly positive in expert coverage and customer impressions.

Expert reviews cite strong CADR/CFM numbers that support the large-room use case.

The lock is treated as a helpful control safeguard, especially for keeping children from changing settings.

Child lock is praised in video walkthroughs as useful for preventing setting changes.

Most arrival comments are incidental, but one customer says the unit appeared used and came without instructions.

Arrival condition is mixed, with many fine deliveries but some wrong colors, missing parts, or damaged packaging.

Controls are usually easy and accessible, but isolated failures produced serious frustration.

Support experiences vary sharply, from Shark helping fix or replace a unit to a buyer reporting no response after manual requests.

Customer support is mixed, ranging from fast helpful replacements to unanswered requests and difficult contact.

Owners usually find the purifier attractive or easy to blend into a room, although its large body and front sticker bother a few people.

Design is generally praised for sleek looks and color/panel options despite the unit’s bulk.

The front display is widely liked because it shows air quality clearly, with percentage and particle readouts that feel more useful than simple lights.

Display readability/control lighting evidence is positive for visible air status and lights-off use.

Setup directions are usually enough to get running, but some owners wanted clearer feature explanations or a full manual.

Documentation evidence is limited and mixed, especially around missing or insufficient manuals.

Durability evidence is positive among long-term users but offset by some failures.

Dust control is a major strength in owner feedback, with many noticing less dust on furniture, floors, shelves, and in pet-heavy rooms. A few saw no dust improvement or had a failing unit blow dust back out.

Dust reduction is often praised, but a few reviews report little visible dust improvement.

Setup, daily controls, and basic cleaning are usually described as simple, quick, and intuitive.

Setup and everyday operation are usually described as easy or simple, with limited exceptions.

Auto and Eco behavior is viewed as a practical way to avoid running the fan harder than needed, and one owner noticed little change in the electric bill.

Energy use is generally described as low or reasonable for such a large purifier.

Reviewers appreciate having manual fan speeds plus Auto mode, though high settings are much more noticeable.

Fan speed options are appreciated for quiet sleep settings and turbo cleaning.

The five-year filter promise is a major buying reason and a value win for many owners. Heavy dust, pets, grit, or frequent use make some reviewers skeptical that it is truly 'never change.'

Filter life is generally viewed positively at roughly 12-18 months, though replacement cost remains a concern.

Many buyers like avoiding frequent replacement filters, but complaints appear when the main filter needs earlier replacement or when buyers compare the unit's price to occasional operation.

Filter replacement cost/subscription requirements are one of the recurring negatives.

The multi-layer filter stack is seen as a serious setup for particles, odors, dander, and smoke.

Handle and wheels help move the large unit, but wheel placement is not universally liked.

Opinionated evidence was found for this attribute in the listed reviews.

The HEPA filter is consistently treated as a core strength, especially because it is paired with protective pre-filters to extend life.

HEPA filtration is repeatedly described as effective or substantial.

Dimming and night-display options are useful for bedrooms and TV rooms, and the color ring helps owners read air quality from a distance.

Indicator lights are valued for quick air-quality feedback and night-light control, with some false-reading complaints.

The 'NeverChange' promise and coverage claims create mixed reactions: many like the concept, while some consider it overstated or misleading.

Listing accuracy is mixed, with “as advertised” praise and a mold-removal complaint.

Most people find the side screens easy to wipe, vacuum, or rinse, but pet hair, desert dust, and gritty homes can turn maintenance into a frequent chore.

Maintenance is usually considered easy due to accessible panels, vacuumable pre-filters, and simple filter changes.

Normal operation is usually quiet or barely noticeable, especially on low and Auto. Complaints cluster around high-speed ramp-ups, defective/noisy units, and the fan becoming loud during cooking or poor air quality.

Low-speed noise is a major strength; high speeds can be more audible.

Cooking, pet, litter, musty, smoke, and general household odors are among the most common wins. The purifier is less convincing for some smoke situations and for people expecting the scent pod alone to do the work.

Odor evidence is mixed-positive: many note fresher air or cooking/smoke odor help, while some report plastic/filter smells.

Overall sentiment is strongly positive, with many repeat purchases and strong recommendations. Negative reviews usually involve defective units, early failures, noise, or disappointment with the filter-life promise.

Overall satisfaction is mostly high, with negative outliers tied to defects, odor, price, or support.

Independent ozone testing found no measurable ozone, which supports continuous-use confidence.

Expert tests and owner reports both point to strong particle reduction, especially for PM readings, dust, smoke particles, pet hair, and airborne debris.

Particle removal is supported by expert tests and dust/particle customer reports.

Pet owners repeatedly say it helps with fur, dander, litter-box odor, dog smell, and the general air quality challenges of multi-pet homes.

Pet dander and pet odor evidence is positive from pet-owner reviews and filter discussions.

PM2.5 and related particle readouts are valued because owners can see what changes during cooking, smoke, windows opening, or cleaning.

Despite being a large floor unit, reviewers often say it is light enough to move between rooms when needed.

Energy comments are limited, but Auto/Eco use and one owner's electric-bill experience suggest it can run without feeling wasteful.

The removable side pre-filters are a standout feature because they trap hair, dust, and lint before the main filter loads up.

Owners like seeing live air-quality percentages and particle data; it turns cooking smoke, candles, pets, and dust into visible feedback.

Real-time monitoring is a useful feature through lights, sensors, app readings, and graphs, though not always trusted.

Reliability is the most uneven area: plenty of owners report months of trouble-free use, while others had red rings, failures, defective sensors, or units that stopped working after cleaning.

Reliability is mixed: some units ran for years, while others shut off, failed, or would not turn off.

Remote control is a minor frustration because some sources say it is sold separately or missing, so across-room control is not built into the box.

Replacement experiences are mixed, with some waiting on replacements or paying shipping after troubleshooting while others simply shop for replacement filters.

Replacement experience ranges from fast and hassle-free to defective or frustrating.

Large-room coverage is one of the reasons people buy it, and many say it suits open floor plans, apartments, main floors, or large shared spaces. Walls and segmented layouts can limit how much of a home it realistically covers.

Large-room coverage is strongly supported across expert reviews and customer use in big rooms, offices, lofts, basements, and open plans.

A customer noted room-temperature improvement from better air mixing.

The timer gives buyers simple run-time control for up to 12 hours. Shoppers wanting app-based schedules or more advanced automation may find the controls limited.

The Max is visibly large, but many owners accept the size for its coverage and some say it still fits neatly in corners or shared rooms.

The main physical drawback is size: the 75i is large, bulky, and not easy to hide.

Dim and lights-off settings are praised for bedrooms because the purifier can keep running without a bright display.

Bedroom/sleep use is positive because of quiet low speeds and light shutoff.

Reviewers mention this attribute in concrete use, with experiences varying by room conditions and expectations.

Sleep quality benefits appear in multiple allergy/asthma customer reports.

Smart-feature feedback is mostly negative or limited because app control and robust connected features are absent.

Smoke feedback is strong for cooking smoke, candles, incense, wood smoke, cigarettes, cigars, and vaping, though heavy smoke can take longer or remain incomplete.

Reviewers see the HEPA element as legitimate and central to the product's particle-removal promise.

The value case is strongest when buyers care about large coverage and fewer filter purchases. It weakens for anyone who gets a defective unit, needs early filters, or wants stronger smart/VOC features.

Value is polarized because many find the performance worth it while others object to purchase and filter costs.

VOC confidence is limited: carbon and gas filtration are mentioned, but one review says genuine VOC mitigation is not a reason to choose this model.

Reviewers mention this attribute in concrete use, with experiences varying by room conditions and expectations.

Washable side screens are repeatedly praised for being easy to remove, rinse, vacuum, and reuse.

Wi-Fi feedback is really about absence, not dropouts: reviewers note this model lacks Wi-Fi or app connectivity.