Until recently, Winix didn’t offer small air purifiers, which made it difficult to compare its lineup with small devices like the Blueair 511i Max.
However, after testing the new Winix A231, I believe this is the perfect chance to make a direct comparison with the Blueair.
What stands out about these two models is that they have nearly identical CADR ratings and are designed for rooms of almost the same size.
The Winix A231 is suitable for spaces up to 230 sq. ft. (21 m²), while the Blueair 511i Max is rated for slightly larger areas, up to 236 sq. ft. (22 m²).
In the following sections, I will compare their specifications in detail and share my opinion on which air purifier I believe is the better choice.
Our Verdict
Although this was a very thorough test, I must highlight that both models have their advantages and disadvantages.
In my opinion, however, the Blueair 511i Max is the slightly better choice overall — even though it showed somewhat weaker results in the airborne particle removal test and is not as well-optimized for noise.
The Blueair performed better in the smoke test, is much more affordable to maintain, and comes with far more advanced features. Taken together, these factors make it, in my view, the better overall option.
If you have any questions about these two air purifiers, feel free to leave a comment below.
Specs: Blueair 511i Max Vs Winix A231
| Product Image |  29% off |  21% off |
| Manufacturer | Blueair | Winix |
| Model | 511i Max | A231 |
| Dimensions (inches / cm) | 10.6 x 10.6 x 18.9 inches (26.9 x 26.9 x 48 cm) | 9.5 x 9.5 x 14.6 inches (24.1 x 24.1 x 37.1 cm) |
| Weight (pounds / kg) | 4.2 lb (1.9 kg) | 6.75 lb (3.1 kg) |
| Clean Air Delivery Rate (CADR) | 152 CFM (258 mÂł/h) | 147 CFM (250 mÂł/h) |
| Coverage (4.8 ACH)
Room Coverage Explanation: ACH is a measurement used in indoor air quality management to indicate how many times the air within a defined space is changed/moved through the filter media.
For more details, visit our ACH calculator tool. | 236 sq. ft. (22 m²) | 230 sq. ft. (21 m²) |
| Performance Ratings Performance Ratings Score Summary: 8.3 - Average Score (101 products) 9.9 - Best Score (1 products) 1 - Worst Score (1 products) We use the Temtop LKC-1000S laser particle meter to test the particle removal efficiency of every air purifier. It measures PM2.5 (µg/m3), PM10 (µg/m3), Particles (per/L), and HCHO (mg/m3) in the air, and also calculates the AQI. You can read more about our testing methodology here. | ||
| Filtration Technology | Washable Pre-filter, Particle Filter, Activated Carbon Filter, and HEPASilent | Pre-filter, Activated Carbon Filter, True HEPA Filter, and PlasmaWave |
| Filter Replacement Indicator | Yes | Yes |
| Filter Life | up to 9 months | up to 12 months |
| Power Consumption
Power Usage Summary: Our extensive testing of 101 air purifiers revealed the following power consumption insights:
Check out our power consumption calculator tool. | 20W | 55W |
| Operating Costs Ratings Operating Costs Ratings Score Summary: 8.9 - Average Score (101 products) 10 - Best Score (2 products) 1.7 - Worst Score (1 products) We measure the power usage at all speeds using an energy meter, after which we calculate how much it would cost to use the device at a particular fan speed for one month. For reference, we use an energy price of $0.12 per kWh. You can read more about our testing methodology here. | ||
| Number of Fan Speeds | 4 - Sleep Mode, Speed 1, Speed 2, and Speed 3 | 4 - Sleep Mode, Low, Medium, and High |
| Air Quality Sensor Air Quality Sensor Summary: Out of 101 air purifiers tested, only 51 have the air quality sensor. | Yes | Yes |
| Air Quality Indicator | Yes | Yes |
| Auto Mode Auto Mode Summary: Out of 101 air purifiers tested, only 52 have auto mode functionality. | Yes | Yes |
| Smart App Smart App Summary: Out of 101 air purifiers tested, only 30 have smart app functionality. | Yes | No |
| Voice Control Voice Control Summary: Out of 101 air purifiers tested, only 29 have voice control functionality. | Yes | No |
| Other Features | Washable Pre-filter | Sleep ModePlasmaWave |
| Noise Level (low – high) | 40.1 – 61.6 dBA | 40.2 – 66.5 dBA |
| Noise Ratings Noise Ratings Score Summary: 9.2 - Average Score (101 products) 10 - Best Score (1 products) 7.6 - Worst Score (1 products) We use a special noise measurement tool to test the noise level of the air purifier at all speeds. We measured the noise level on the dBA scale. You can read more about our testing methodology here. | ||
| Best Suited For | Bedrooms Allergies Small Spaces Dust Low Energy Cost | Bedrooms Small Spaces Dust Allergies Children's Rooms |
| Warranty | 3-year | 2-year |
| In-Depth Review | Blueair 511i Max | Winix A231 |
| Price |
Performance Test – Comparison
According to their CADR ratings, we tested the performance of both models in two rooms of identical dimensions.
In the first test, performed in a 194 sq. ft. (18 m²) room, the Blueair 511i Max improved air quality by about 92%, while the Winix A231 achieved roughly 95%.
Particle Removal Tests - Comparison
We placed the Blueair 511i Max and Winix A231 in two separate tests and measured their performance using the Temtop laser particle meter.
In the second test, performed in a larger 320 sq. ft. (30 m²) room, the Blueair 511i Max improved air quality by about 90%, compared to 92% for the Winix A231.
Overall, the Winix delivered slightly better results in the airborne particle removal test. To be fair, I expected both devices to perform almost the same, mainly because their room coverage ratings are nearly identical.
Smoke Box Test – Comparison
In addition to the airborne particle removal tests, we also evaluated how quickly these two air purifiers could remove smoke from a sealed glass box.
For this test, we placed each device inside the box, filled it with smoke, and measured the time it took, at maximum speed, to clear it completely.
The Winix A231 needed about 25 seconds to remove all the smoke, while the Blueair 511i Max accomplished the same task in just 20 seconds.
Despite both devices using a fibrous filter coated with carbon and having nearly identical CADR ratings, the Blueair still outperformed the Winix in this test.
Noise Level Test – Comparison
The first thing I want to point out about the noise test is that both devices feature four fan speed settings.
Interestingly, although the Blueair 511i Max achieved better results in measurements, it actually received a lower overall score than the Winix A231.
The reason is that the Blueair produces a noticeable high-pitched whistling sound when the motor is running, especially at maximum speed, which I personally found quite annoying.
Noise Levels - Comparison
Comparison of noise levels at all fan speeds between the Blueair 511i Max and Winix A231 air purifiers.
At the lowest speed, the Blueair 511i Max produces 40.1 dBA, while the Winix A231 produces 40.2 dBA.
At maximum speed, the Blueair 511i Max produces 61.6 dBA, compared to 66.5 dBA for the Winix A231.
All in all, this turned out to be one of the rare cases where the device with slightly worse measured results in our noise tests still came out on top. In this case, the winner was the Winix A231.
Operating Costs – Comparison
In many of my reviews and comparisons, I often point out that the Blueair 511i Max is very difficult to beat in power usage tests.
The reason is simple — Blueair designs highly optimized motors. In this case, the Blueair 511i Max is equipped with a motor rated at just 20W, while the Winix A231 relies on a much larger 55W motor.
Monthly Power Consumption Cost - Comparison
Comparison of monthly power consumption costs for the Blueair 511i Max and Winix A231 air purifiers at all fan speeds.
Considering that both models deliver a similar CADR, it’s clear that the Blueair is far more efficient in terms of energy consumption.
If you were to run both air purifiers at maximum speed, 24 hours a day, for an entire month, your electricity bill would increase by about $3.56 with the Winix, compared to only $1.56 with the Blueair.
Taking into account that the filters on both devices can last up to 12 months under ideal conditions, and that the Winix replacement filter is slightly more expensive, it’s easy to conclude that the Blueair 511i Max is not only better optimized but also significantly more affordable to maintain on a yearly basis.
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