SIDE BY SIDE

Compare products.

See prices, running costs, specifications and trade-offs side by side. Choose two to four products of the same type.

Change products

Product 1Product 2Product 3 (optional)Product 4 (optional)

Portable air purifier

Alen BreatheSmart 45i

US BreatheSmart 45i

$449US price, checked Oct 13, 2026

Slim, quiet HEPA purifier with a guarantee tied to Alen filters

Check price at Alen Full review →

Portable air purifier

Coway Airmega AP-1512HH Mighty

US AP-1512HH / AP-1512HH(W)

$239.99US price, checked Oct 13, 2026

Compact purifier for rooms up to about 360 ft², with filters near $60 a year

Check price at Coway Full review →

Criterion	Alen BreatheSmart 45i	Coway Airmega AP-1512HH Mighty
US price	$449Checked Oct 13, 2026 · Price details in the review	$239.99Checked Oct 13, 2026 · Price details in the review
Three-year ownership estimate	$725 Incomplete known subtotal. Not included: energy use.	$419.36 Incomplete known subtotal. Not included: energy use.
Choose if	You want a quiet, slim HEPA purifier for one large room and don't mind buying Alen filters every year.	A bedroom or living room up to about 360 ft² where you want cheap yearly filters and simple controls.
Main trade-off	Filters add $69 to $198 a year, and Alen gives its own airflow figure instead of AHAM smoke, dust and pollen ratings.	Coway publishes only one power figure and a noise range, and no independent listing for this model could be confirmed.
Key specifications	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.	CADR (smoke, dust, pollen): 233, 246 and 240 Room size: 361 ft² at 4.8 air changes an hour (one change every 12.5 minutes); 874 ft² at 2; 1,748 ft² at 1 Noise: 24 to 53 dB(A); no per-speed breakdown Power draw: 77 W; Coway gives one figure, not high and low Filters: Washable pre-filter, deodorization filter and HEPA filter, plus an ionizer you can switch off Filter life and price: HEPA 1 year, deodorization 6 months; $59.79 Fresh Starter set (1 HEPA, 2 deodorization), $64.99 Allergen, Intense Smoke or Pet set Controls: Auto, speeds 1 to 3 and Eco; 1, 4 or 8 hour timer; dust sensor, air quality light and filter indicator Size and weight: 16.8 × 18.3 × 9.6 in; 12.3 lb
Exact variant	US BreatheSmart 45i	US AP-1512HH / AP-1512HH(W)
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.	16.8 × 18.3 × 9.6 in (width × height × depth), or 43 × 46 × 24 cm. It weighs 12.3 lb (5.5 kg).
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.	No installation. It sits on the floor and plugs into a standard 120 V outlet. The manual asks for at least 20 cm (about 8 in) from walls and other objects. Leave 30 to 60 cm of open space above it. Keep it 2 m from a TV or other electronics, off sloped surfaces and out of direct sunlight. It's meant for indoor household use.
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.	Four stages: a washable pre-filter, a deodorization filter, a HEPA filter and a bipolar device. The manual calls that last stage the ionizer and gives it its own on/off button. The filter set page describes the deodorization filters as carbon filters for odors and gases.
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.	Coway's manual covers the motor and electronic parts for 3 years from the original retail purchase. Internal and functional parts get 1 year. Coway's support list also puts the AP-1512HH under 3-year coverage. Claims need proof of purchase and a video of the problem. Filters aren't listed as covered. Problems caused by non-genuine filters, skipped filter changes, or commercial or office use are excluded.
Returns	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.	The product page offers a 30-day money-back guarantee and "30 days free return", with an asterisk pointing to the return policy. That policy gives you 30 days from the ship date to request a return. It also says you pay shipping, handling and processing costs unless Coway made the error. If parts are missing, Coway may charge a restocking fee of 15% of the price or the value of the missing parts, whichever is higher. Refunds go to the original payment method. The policy doesn't say whether opened filters can be returned.
Unresolved questions	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	Whether it's listed in AHAM's Verifide directory or Energy Star's certified product list; neither could be checked Whether CARB certified the AP-1512HH; the readable part of CARB's list stopped at entries from November 2025 Power draw on low and Eco, and which speed the 77 W figure refers to Noise at each fan speed Standby power Whether opened filters can be returned What differs inside the Allergen, Intense Smoke and Pet filter sets

These comparisons use published specifications, not head-to-head tests. Prices and terms are dated. Unknown costs are not zero. Check the exact variant before you buy.