Updated September 30, 2026 · SmartHomeCue Editorial Team
AirDoctor vs Alen Air Purifiers
What sets them apart
| Compare |  AirDoctor | Alen Air Purifiers ReviewVisitVisit |
|---|---|---|
| Reference models | AirDoctor 2000, AirDoctor 3500, AirDoctor 5500 | BreatheSmart 75i, BreatheSmart 45i, BreatheSmart 35i |
| Price from | $399 | $149Lower |
| Clean air delivery rate (m³/h) | 944.64Higher | 637.125 |
| Room size (m²) | 96.9 | 260.13Higher |
| Filter cost per year | $126.99 | $79.20 to $99Lower |
| Filter change interval | 6 to 12 months | 12 to 15 monthsHigher |
| Markets | US, CACovers more | US |
| Quietest noise level (dB) | Not confirmed | 25 |
| Power use (W) | Not confirmed | 1.36 to 55 |
Same on both: Mobile app (Yes), Warranty (1 year).
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Key differences
- Alen Air Purifiers scores higher overall: 8.9 vs 8.7.
- Price from is lower at Alen Air Purifiers: $149 vs $399.
- Clean air delivery rate (m³/h) is higher at AirDoctor: 944.64 vs 637.125.
- Room size (m²) is higher at Alen Air Purifiers: 260.13 vs 96.9.
- Filter cost per year is lower at Alen Air Purifiers: $79.20 to $99 vs $126.99.
- Filter change interval is higher at Alen Air Purifiers: 12 to 15 months vs 6 to 12 months.
- Support channels: only AirDoctor offers Email.
- AirDoctor is available in 1 more country.
- Filter types: only Alen Air Purifiers offers Ioniser.
- Markets: only AirDoctor offers CA.
Our verdict on each
AirDoctor
AirDoctor suits households that want serious airflow in a mid-size room and can absorb a higher outlay. The top model moves 944.64 m³/h of air, the range starts at $399 in US and CA, and replacement filters add $126.99 each year.
Alen Air Purifiers
Alen Air Purifiers suits buyers who want a single machine covering a large open floor and will keep it running for years. The top BreatheSmart purifier delivers 637.125 m³/h of clean air delivery for a 260.13 m² room, and the entry tower purifier opens the range at $149.
Score breakdown
| Area | AirDoctor | Alen Air Purifiers |
|---|---|---|
| Cost | 8.3Entry of $399 plus $126.99 of filters a year keeps the outlay high, ranking 69 of 76. | 8.8HigherEntry at $149 and filters at $79.20 to $99 a year, so the purchase price is the expensive part. |
| Offer | 9.0HigherThe range pairs hepa h13 and carbon media with a mobile app, 944.64 m³/h of airflow, US and CA sales and a 1 year warranty. | 8.9637.125 m³/h of air delivery, 260.13 m² of coverage and hepa h13, carbon and ioniser inside 12 to 15 months. |
| Trust | Not confirmed | 8.8Alen Corporation is named as the legal entity, with 1 year cover and support on phone and help centre. |
Where they rank in our lists
| Ranking | AirDoctor | Alen Air Purifiers |
|---|---|---|
| Air purifiers | 8 of 71 | 7 of 71 |
A third option
AlorairCrawlspace has room size (m²) at 93 to 418, against 96.9 for AirDoctor and 260.13 for Alen Air Purifiers.
AlorairCrawlspace reviewEvery fact side by side
| Fact | AirDoctor | Alen Air Purifiers |
|---|---|---|
| Products | Purifier | Purifier |
| Filter types | Hepa h13, Carbon | Hepa h13, Carbon, IoniserCovers more |
| Certifications | Not confirmed | Energy star |
| Legal entity | Not confirmed | Alen Corporation |
| Headquarters | Not confirmed | United States |
| Support channels | Email, Phone, Help centreCovers more | Phone, Help centre |
Where each stands against the rest
| Fact | AirDoctor | Alen Air Purifiers | Median |
|---|---|---|---|
| Price from | $399highest quarter | $149above the median | $109.99 |
| Clean air delivery rate (m³/h) | 944.64highest quarter | 637.125above the median | 424.925 |
| Room size (m²) | 96.9below the median | 260.13highest quarter | 124 |
| Filter cost per year | $126.99highest quarter | $79.20 to $99below the median | $79.60 |
| Filter change interval | 6 to 12 monthsat the median | 12 to 15 monthshighest quarter | 12 |
| Quietest noise level (dB) | Not confirmed | 25at the median | 25 |
Median across 65 listed brands.
Pros and cons
AirDoctor
Pros
- Airflow is the standout number: the top AirDoctor purifier moves 944.64 m³/h and covers 96.9 m².
- Filter media combine hepa h13 and carbon in the same cartridge, so particles and odours are handled together.
- Replacement spending is easy to forecast: a year of AirDoctor filters costs $126.99.
Cons
- An entry price of $399 places AirDoctor at 69 of 76 brands on price from, well down the table.
- Filter running cost is the weakest link: $126.99 a year ranks 37 of 46.
- Sales run in US and CA, which narrows where the range can be bought and serviced.
Alen Air Purifiers
Pros
- 637.125 m³/h of clean air delivery with 260.13 m² of stated coverage, so a single unit handles a big open room.
- Filters last 12 to 15 months and cost $79.20 to $99 a year, which spreads the running cost over fewer purchases.
- Runs at 25 dB on the quietest setting, so a machine in a bedroom does not need switching off at night.
Cons
- Entry price of $149 ranks 49 of 76 brands, so this is not the cheapest way into the category.
- The catalogue is limited to purifier, so Vornado Air or Daewoo Electricals suit a buyer who also wants a fan or a dehumidifier.
- Availability is listed for US alone, so a buyer elsewhere has less reason to choose this brand over Clarifion.
Who each suits
AirDoctor
Who it suits
- Households in US and CA who want app control and top-end airflow from the top AirDoctor purifier.
- Buyers who budget filter spending in advance, since a year of filters costs $126.99.
- Anyone upgrading a purifier for a mid-size room, where the top model covers 96.9 m².
Who should look elsewhere
- Vornado Air, which covers purifier, humidifier and fan if you want a purifier sitting alongside fans and humidifiers.
- Daewoo Electricals, whose purifier, dehumidifier and fan line adds a dehumidifier where AirDoctor's range stays with purifier.
- Clarifion, whose models centre on ionizer and pet smell units, a different route from AirDoctor's hepa h13 and carbon media.
Alen Air Purifiers
Who it suits
- US buyers who want a single purifier sized for a large open room rather than a small bedroom.
- Households that want app control alongside phone and help centre support from the maker.
- Owners who plan to keep one unit running long term, since 12 to 15 months between filter changes spreads the cost of $79.20 to $99 a year over fewer purchases.
Who should look elsewhere
- Buyers who want fans and humidifiers as well as purifiers, since Vornado Air covers purifier, humidifier and fan.
- Homes that also need drying, since Daewoo Electricals covers purifier, dehumidifier and fan.
- Pet odour cases, since Clarifion lists a pet smell neutralizer among its models.
Country by country
| Country | AirDoctor | Alen Air Purifiers |
|---|---|---|
| Canada | Yes | No |
| United States | Yes | Yes |
Questions about each
AirDoctor
How much does an AirDoctor purifier cost to start with?+
The AirDoctor purifier range starts at $399, and that figure buys the entry model rather than the top of the range. The listed models are AirDoctor 2000, AirDoctor 3500, AirDoctor 5500, so buyers who want the highest airflow step up the range rather than sideways.
What do replacement filters cost over a year?+
Filters are the running cost here: $126.99 covers a year of AirDoctor replacement filters. The top AirDoctor purifier asks for a change on a cycle of 6 to 12 months, so a year of heavy use can mean ordering more than a single pack.
Alen Air Purifiers
How much does the cheapest Alen purifier cost?+
The entry tower purifier sets the entry point at $149. Filters for the top BreatheSmart model add $79.20 to $99 a year on top, so the yearly figure matters as much as the sticker price for anyone keeping the unit for years.
What do replacement filters cost and how often do they need changing?+
Filters for the top BreatheSmart model run $79.20 to $99 a year, and filters hold for 12 to 15 months between changes. That interval sits above the 6 months typical across the category, which is why the yearly figure reads as reasonable.