Our pick if it has to go on the wall
Rabbit Air MinusA2
Slim wall-mount purifier for rooms near 280 ft², with $95 yearly filters
$599.95
Compare with this one →Portable air purifier
AlenBreatheSmart 45i
Slim, quiet HEPA purifier with a guarantee tied to Alen filters
Source-based analysis, not hands-on testing. Our method
Cofounder of Superhuman Chambers · About the author.
The verdict
The BreatheSmart 45i is a quiet, slim panel purifier for steady cleaning of a large room. Its 255 CFM rating means one air change an hour across Alen's 1,900 sq ft claim, so it won't clear smoke fast. The catch is the filters: $69 to $99 each, and the guarantee lasts only while you keep buying them.
The trade-off
Filters add $69 to $198 a year, and Alen gives its own airflow figure instead of AHAM smoke, dust and pollen ratings.
Model reviewed: US BreatheSmart 45i
$449
Check price at Alen US price, checked
No affiliate commission on this link. Check the exact variant before buying.
About this price
List price for the White panel with the Essential (Pure) filter, purifier only, with one filter in the box. The other five panel finishes cost $488. The Advanced (Fresh) filter adds $15 and the Ultimate (Odor) filter adds $30. A site-wide fall sale banner was up, but no discount showed on the 45i. Alen's online store listed every finish and filter combination as available. The price is before tax, and Alen advertises free 2-day shipping.
A GOOD FIT FOR
You want a quiet, slim HEPA purifier for one large room and don't mind buying Alen filters every year.
- A large living room or open-plan space where steady cleaning at one or two air changes an hour is enough
- A bedroom, if you want a 24 dB low setting and a steady pink-noise sound
- You want a slim purifier, 8.5 in deep, with a choice of six front panels
- You'll buy Alen filters every year anyway and want the extended guarantee
THINK TWICE IF
- You need fast smoke clean-up in a big room: 255 CFM is about two air changes an hour in 950 sq ft
- You want the lowest filter bill, since the carbon filters cost $89 to $99 every 6 to 8 months
- You want an AHAM-verified smoke, dust and pollen CADR to compare brands, which Alen doesn't publish
- You'd rather not register the unit or keep proof of filter purchases to stay covered
What still needs checking
- Smoke, dust and pollen CADR from AHAM or Energy Star testing
- Whether CARB's own list includes the 45i (Alen's linked order file has no readable text)
- Average power on auto, so the yearly electricity cost
- Whether the store ships the original 45i or the touch-control 45i V2 named in Alen's CARB and Energy Star files
- The true size and weight, since Alen's product page and support table disagree
- How long a filter lasts if you don't run it around the clock
- How often subscription filters ship
The practical details.
| Exact variant | US BreatheSmart 45i |
|---|---|
| Clean air delivery rate | 255 CFM on high by Alen's own CADRi figure; 80, 120 and 190 CFM on the lower speeds. No separate smoke, dust or pollen CADR on Alen's page. |
| Room size | 950 sq ft at 2 air changes an hour or 1,900 sq ft at 1, by Alen's figures. Its FAQ says up to 1,600 sq ft. |
| Noise | 24 dB on the lowest speed to 50 dB on high |
| Power draw | 1.6 to 64 W in the spec table; the FAQ says 50 W on high. Alen doesn't say which setting draws 1.6 W. |
| Filter life | Essential (Pure) 9 to 12 months; Advanced (Fresh) and Ultimate (Odor) 6 to 8 months, running 24/7 |
| Filter price | $69, $89 or $99 each; 10% off on subscription ($62.10, $80.10 or $89.10) |
| Ozone | Optional ionizer: under 0.001 ppm when on, 0 ppm when off. Alen lists CARB certification. |
| Dimensions | 25 in high, 15 in wide and 8.5 in deep, and 14 lb, according to the product page. Alen's support table lists the 45i/FLEX at 19 × 11 × 28 in and 23 lb. That's the same size it gives for the shipping box. |
| Materials | One filter cartridge with a prefilter you can vacuum. Essential (Pure) is a True HEPA (H13) filter aimed at dust, pollen, dander, mold and allergens. Advanced (Fresh) adds activated carbon for VOCs, smoke and cooking odors. Ultimate (Odor) adds an odor neutralizer for pet and diaper smells. An optional ionizer can be turned on or off. The front panel comes in White, Oak, Weathered Gray, Brushed Stainless, Graphite or Espresso. |
Before you buy
InstallationFreestanding, with no installation
Freestanding, with no installation. It runs from a 24 V external power adapter. The manual asks for a level surface at least 6 in from heat sources such as heaters, with the vents left clear. The Alen Air app adds remote control, scheduling and filter alerts over Wi-Fi.
WarrantyAlen gives a 1-year manufacturer's warranty
Alen gives a 1-year manufacturer's warranty. Its Forever Guarantee extends that if you register the serial number and use only Alen filters. You also need an active filter subscription or proof of an Alen filter purchase in the last 12 months. If troubleshooting can't fix a fault, you get a new unit in year two. From year three you get a refurbished or reconditioned unit, and the guarantee page sets no end date. Alen's support page says to register within 12 months of purchase. The guarantee doesn't transfer and excludes accidental damage, floods and fires. The product page says it needs an active subscription, but the guarantee page also accepts a recent filter purchase.
Returns60-day trial on orders from alen.com
60-day trial on orders from alen.com. Alen refunds the purchase but deducts return shipping, using a FedEx label it emails you. Opened filters can't be returned. The refund can take up to 7 business days after the warehouse receives the return. Orders from other retailers go back through that retailer. Alen doesn't say whether the 60 days start at purchase or delivery.
More about this assessment
The BreatheSmart 45i is Alen's slim HEPA panel purifier, 8.5 in deep, at a $449 list price. Alen rates it at 255 CFM on high, about two air changes an hour in 950 sq ft. That's fine for steady cleaning of a big room but slow for smoke. Filters add $69 to $198 a year, depending on the type. Coverage past year one needs registration plus a filter subscription or an Alen filter bought in the last 12 months. Alen doesn't publish AHAM smoke, dust and pollen ratings, and Energy Star's certified list doesn't include the 45i.
Strengths on paper
- Quiet on low at 24 dB, and 50 dB on high
- Slim panel shape, 25 in tall and 8.5 in deep, at 14 lb
- Particle sensor and auto mode that change the fan speed for you
- All three filters are True HEPA, and two add carbon or an odor neutralizer
- The guarantee has no stated end date if you register and keep buying Alen filters
- 60-day trial with a refund, minus return shipping
Limitations
- Alen quotes its own 255 CFM CADRi figure, not separate AHAM smoke, dust and pollen ratings
- The 1,900 sq ft claim means one air change an hour, a slow rate
- Filters add $69 to $198 a year, depending on the type
- Guarantee cover past year one depends on registration and a recent Alen filter purchase
- Alen's own pages disagree on coverage (1,600 or 1,900 sq ft), peak power (50 or 64 W) and size
- Alen calls it Energy Star certified, but Energy Star's certified list doesn't include it
- The ionizer gives off a trace of ozone when on, though you can switch it off
- Return shipping comes out of your refund, and opened filters can't be returned
What it costs to own.
Adjust the assumptions for your use. Missing costs stay unknown.
PLAN YOUR OWNERSHIP COSTS
What will it cost to own?
Change the assumptions to fit your use. Leave an unknown cost blank. Add water, subscriptions, cleaning, shipping and taxes if they apply. Use average operating power, not the maximum rating.
3-year known subtotal
$725.00Incomplete: energy use. This is not the full ownership cost.
Energy component: Unknown
Purchase + installation + years × (annual consumables + annual other) + watts/1000 × hours/day × 365 × years × $/kWh. Annualized allowances, not an exact replacement schedule. Excludes taxes, shipping, finance and resale unless entered.Replacement parts & cost assumptions
Recorded recurring parts and refills:
- Essential (Pure) True HEPA filter: $69 every 9 months. Alen says 9 to 12 months running 24/7. $62.10 on a filter subscription. A 5-pack was on sale for $293, down from $345.
- Advanced (Fresh) HEPA and carbon filter: $89 every 6 months. 6 to 8 months running 24/7. $80.10 on a filter subscription.
- Ultimate (Odor) HEPA and odor filter: $99 every 6 months. 6 to 8 months running 24/7. $89.10 on a filter subscription.
- Purchase is the $449 list price for the White panel with the Essential (Pure) filter, purifier only.
- Filters assume the $69 Essential (Pure) filter, replaced every 9 months: $92 a year. At 12 months it's $69 a year. A subscription cuts each filter to $62.10.
- The Advanced (Fresh) and Ultimate (Odor) filters last 6 to 8 months. That's about $134 to $198 a year at one-time prices.
- Hours per day is 24 because Alen's filter-life figures assume 24/7 running.
- Energy is unknown. Alen gives a 1.6 to 64 W range but no average. Running on high around the clock at 64 W would use about 561 kWh a year.
- Other yearly costs are $0. The filter subscription is optional, and what it charges is the filters counted above.
- Installation is $0: it's freestanding, and Alen advertises free shipping.
Evidence & sources.
Do air purifiers work? Our evidence review grades the research as Strong. That grade is about the claim, not about this product.
- Manufacturer claimAlen rates the 45i at 255 CFM on high, its CADRi figure. It says the 45i cleans 1,900 sq ft every hour or 950 sq ft every 30 minutes.1 Alen's own figures. The product page doesn't mention AHAM or give smoke, dust and pollen ratings.
- Manufacturer claimAlen lists the 45i as CARB certified for ozone emissions and electrical safety. It links a 45i V2 file named for executive order G-25-209. The manual gives an 8-hour ozone level of 0.001 ppmv in a 30 m³ test chamber.78 From Alen's certifications page and manual. Not confirmed on CARB's own list, and the linked file has no readable text.
- Manufacturer claimAlen says the 45i is Energy Star certified, verified by Intertek, and achieved Energy Star's 2025 Most Efficient designation.18 From Alen's product and certifications pages. Energy Star's own data doesn't back this up (see below).
- CertificationEnergy Star's certified room air cleaner data lists three Alen models, the BreatheSmart 25i, 35i and 75i_V2. The 45i isn't among them.9 Searched by brand, by "BreatheSmart" and by "45i". Without a listing, there are no Energy Star smoke, dust and pollen CADR or yearly energy figures for the 45i.
- Manufacturer claimThe product page shows Asthma & Allergy Friendly, Quiet Mark and SleepScore Validated badges, and says 93% of users reported improved sleep.1 Alen gives no study name, sample size or method for the 93% figure. No published study of this model's effect on sleep or health was reviewed.
Sources (9)
- BreatheSmart 45i official US product page Alen · manufacturer · checked Oct 13, 2026
- Unit & Filter Dimensions & Shipping Weights Alen · manufacturer · checked Oct 13, 2026
- Product and Warranty Information Alen · manufacturer · checked Oct 13, 2026
- Alen Forever Guarantee Alen · manufacturer · checked Oct 13, 2026
- 60-Day Satisfaction Guarantee Alen · manufacturer · checked Oct 13, 2026
- BreatheSmart 45i replacement HEPA filters Alen · manufacturer · checked Oct 13, 2026
- BreatheSmart 45i V2 product manual Alen · manufacturer · checked Oct 13, 2026
- Alen certifications Alen · manufacturer · checked Oct 13, 2026
- ENERGY STAR Certified Room Air Cleaners V3.0, Alen entries US EPA ENERGY STAR · certifier · data file · checked Oct 13, 2026
Other options.
Back to our air quality picks →
Our pick for a medium room
Blueair Blue Pure 311i Max
Light, quiet purifier for rooms up to 439 ft², with $44.99 filters every 6 to 9 months
$229.99
Compare with this one →
Our pick for a small bedroom or office
Blueair Blue Pure 511
Low-cost purifier for one room up to about 190 ft², with filters at $48 a year
$99.99
Compare with this one →About this review. The facts on this page come from manufacturer pages and certification listings, checked Oct 13, 2026. The sources are listed above.
Our editorial policy →