Air Purifiers / Alen
Alen BreatheSmart 75i (V2)
Best sensors and a lifetime warranty — as long as you never cancel the filter subscription.
Overall score 6.9/10
Pros
- + Publishes actual ozone figures at both ioniser settings — 0 ppm off, under 0.001 ppm on — which almost nobody does
- + PM2.5, TVOC, eCO2, temperature and humidity sensing is the broadest package here
- + 25–51 dBA across the whole range from a genuinely large-room machine
- + Four filter chemistries in one body, so you can retune it for odour or wildfire smoke
- + Interchangeable panels make it the only unit here designed to be seen
Cons
- − The "Forever Guarantee" is conditional on registration AND an active filter subscription — stop buying filters and the lifetime warranty stops
- − "Up to 2,800 sq ft" is a 1-ACH figure; Alen's own CADR implies roughly 580 ft² at the 4.8 ACH that matters
- − Alen's own page states two different CADRs, 375 and 350, in two places
- − Not in the AHAM Verifide directory, so nothing about the CADR is independently confirmed
- − CARB lists the 75i_V2 as an Electronic (ozone-capable) device, and the Odor filter pushes running costs past $165/yr
Alen BreatheSmart 75i (V2) review: what the specs say
Best sensors and a lifetime warranty — as long as you never cancel the filter subscription. At $799, Alen's 2024 model sits at the premium end of the category — the air Purifiers we compare run from $49.99 to $1,014.99. It scores 6.9/10 overall, calculated from published specifications across 8 categories rather than from a subjective impression.
Its strongest showing is Filtration Quality at 8.5/10 — what the media is really rated at — sealed H13, True HEPA, HEPA-Type, EPA 12 or charged fabric — whether the whole machine is sealed so air cannot bypass the filter, and how much genuine activated carbon there is for odours and VOCs. The weakest is Coverage-Claim Honesty at 3.0/10, which is the trade-off to weigh before buying: if that is the specification you care about most, one of the alternatives below will serve you better.
Worth knowing before you buy: the "Forever Guarantee" is conditional on registration AND an active filter subscription — stop buying filters and the lifetime warranty stops; and "Up to 2,800 sq ft" is a 1-ACH figure; Alen's own CADR implies roughly 580 ft² at the 4.8 ACH that matters. Every specification on this page comes from Alen's own documentation or a verified retail listing — where a figure is not published, the table says so rather than estimating it.
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Full Specifications
| AHAM Verifide CADR (Smoke / Dust / Pollen) | Alen publishes a CADR of 375 on the 75i spec block and 350 in its own product description on the same page — Sources conflict: 375 (Alen spec table) vs 350 (Alen product description). Not AHAM Verifide: Alen does not appear in the AHAM Verifide directory in August 2026, so neither figure is independently confirmed, and neither is broken out by smoke, dust and pollen. CFM |
| AHAM Verifide Room Size (4.8 ACH) | Not listed in the AHAM Verifide directory (August 2026). At Alen's own 375 CADR, the equivalent 4.8-ACH room would be about 580 ft², not the 2,800 ft² on the box. ft² |
| Coverage Claim & Its Air-Change Basis | "Covers up to 2,800 sq ft every hour or 1,400 sq ft every 30 minutes" — that is 1 air change per hour and 2 air changes per hour respectively. Alen never quotes a 4.8-ACH figure. The gap between the 2,800 ft² headline and the roughly 580 ft² its own CADR implies at 4.8 ACH is the largest in this file. |
| Filter Grade (True HEPA / HEPA-Type / H13) | True HEPA H13 rated at 99.9% down to 0.1 microns (Alen's wording). Four interchangeable filters: Essential/Pure, Fresh, Odor and Heavy Odor, the latter three adding progressively more carbon. |
| Pre-Filter (Washable?) | Integrated into each filter cartridge — not separately washable |
| Filter Cost per Year | $79.20–$99.00/yr with the Essential (Pure) filter at $99 on Alen's stated 12–15 month interval; $166.80–$238.29/yr with the Ultimate (Odor) filter at $139 on its 7–10 month interval. And note the warranty coupling below: the filter subscription is not optional if you want the lifetime guarantee. |
| Ioniser / UV / PCO & CARB Classification | Yes, and it is switchable — Alen publishes the numbers at both settings: "0 PPM when disengaged, less than 0.001 PPM with ionizer engaged". CARB certifies the BreatheSmart 75i_V2 as an ELECTRONIC device (EO G-24-038, notified 2024-02-26), and the 45i V2 likewise (G-25-209). Ozone-capable by construction, tested at or below 0.050 ppm, and defeatable in software. |
| Noise, Lowest to Highest Setting | 25 dBA lowest to 51 dBA highest (Alen published) dB |
| Air Quality Sensor | The most complete sensing package here: PM2.5, TVOC, eCO2, temperature and relative humidity, driving five colour rings and an auto mode. Note eCO2 on this class of device is normally inferred from the VOC sensor rather than measured with an NDIR CO2 cell, and Alen does not state which it is. |
| Smart Features & Offline Operation | Wi-Fi and the Alen Air app need an account. Fan speed and auto mode work from the panel offline — but the "Forever Guarantee" requires an active filter subscription, which is a commercial dependency rather than a technical one. |
| Power Draw & Annual Energy | 1.36W to 55W across the speed range (Alen published) |
| Warranty Terms & Conditions | "Forever Guarantee | with Product Registration & Active Air Filter Subscription" — Alen's lifetime warranty is conditional on you continuing to buy filters on subscription. Cancel the subscription and the guarantee lapses. warrantyMonths is recorded as 0 because the term is conditional and not expressible in months. |
| Connectivity | 2.4GHz Wi-Fi, Alen Air app |
| Material | ABS housing with interchangeable front panels including wood-effect and brushed-stainless finishes |
| Warranty | 0 months |
Compare Alen BreatheSmart 75i (V2) With
Cheaper Alternative
Dyson Purifier Cool Gen1 TP10 — $479.99
Premium Alternative
Molekule Air Pro with PECO-HEPA Tri-Power filter (SQ2PH-US) — $1014.99