Blueair Classic 205: Can You Measure the Invisible?

Blueair Classic 205: Can You Measure the Invisible?

What is in the air we breathe?

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For nearly a year, I've puzzled about how to review the Wi-Fi-enabled Blueair Classic 205 smart air purifier ($349.99) and its complementary Blueair Aware air monitor ($199.99).

For one thing, the claimed clean air benefits of the Classic 205 are cumulative – essentially better health through better air. So I have waited a year to see how having the Blueair in our apartment affected or improved my health.

But I also encountered an odd reviewer's conundrum: how do I independently confirm the company's claims for the Classic Air 205's air filtering performance and benefits?

But before I broach its efficacy, some Classic 205 and Aware basics.

The Classic 205 is the smallest of the company's new-ish smart room air purifiers, designed to clear the air of airborne pollutants, especially allergy and asthma triggers, in rooms up to 280 square feet. According to Blueair, all the Classics use HEPASilent technology, and its "Classic Particle filter removes 99.97 percent of all airborne pollutants such as ultra-fine particles (PM 2.5), pollen, dust, pet dander, mold, bacteria, and viruses with whisper silent operation."

Its sleek design allows Blueair Classic 205 to seemingly blend into your space, almost disappear.Blueair

More specifically, the Blueair Classic series – which includes the 405 (431 sq. feet, $549.99) and the 605 (775 sq. feet, $749.99) – filters three potentially harmful invisible environmental elements:

  • Particulate Matter 2.5 (PM2.5): small particles up to 2.5 micrometers such as fine dust, mite feces, gasses and odors; according to the Blueair Friend app, these particles can be generated by emissions from traffic and industrial plants, cleaning fluids, beauty products, candles, cooking and smoking, and ought not to exceed concentrations higher than 35 micrograms per cubic meter of air over 24 hours.
  • Total Volatile Organic Compounds (tVOC): which can be one of thousands of different gasses emitted from solids or fluids; the Blueair filters are designed to remove the majority of harmful VOCs from products, cooking and smoking, such as formaldehyde, acetaldehyde (a Group 1 carcinogen) and acrolein.
  • Carbon Dioxide Equivalent (C02): which is estimated, correlated from detected VOCs.

From the Blueair Friend app, when combined with the Aware air monitor, you can monitor the levels of all three along with temperature and humidity. For the Classic, you can remotely turn the Classic unit on/off, toggle between its three fan speed and Automode settings if connected to an Aware, set a night mode, view outdoor air conditions, enable a child lock, adjust its front logo blue LED brightness intensity, and receive filter change notifications. For the Aware, you can view live, day, week or monthly readings on all five elements monitored, view outdoor air conditions, set notification alarms for PM2.5, tVOC, temperature and humidity, and adjust its blue/orange LED brightness intensity.

When you connect the Aware air quality monitor, you also can toggle to Automode as a fan speed so the Classic can automatically adjust the airflow based on detected contaminant levels.

Blueair's app allows you to monitor multiple readings in a room from CO2 to temperature.Blueair


The Classic's filtering capabilities depend on which of the two Blueair filters you choose, the Particle Filter ($49.99-$79.99), which is what my test unit has, and the Smoke Stop Filter ($99.99-$149.99), designed to cover a wider range of pollutants, including cigarette/cigar smoke and cooking odors, but offers "less CADR."

The white Classic 205 measures 21 (W) x 17 (H) x 8 (D) inches, and its filter is easily removable/replaceable via a rear panel. Under a front lid you'll find LED-lit controls/indicators for Wi-Fi, fan speed (three speeds) and filter, the latter of which lights orange when a replacement is needed. The Classic 205 should be placed in a semi-centralized area of the room, at least four inches from anything (such as a wall) to be most effective.

The Aware air monitor measures 7.6 (H) x 3 (W) x 3 (D) inches, with an intersecting vertical LED that glow blue when your air is good, orange when it's not.

When initially setting up the Classic and the Aware a year ago – and each is a separate setup – I encountered all manner of Wi-Fi connectivity issues; setting up the Aware, for instance, requires you to turn it upside down during the process. Supposedly, app updates have addressed the issues I encountered.

Even after you connect both the Classic and Aware, you still have to additionally "+Add Blueair Aware" within the Classic part of the Friend app to enable Automode, which seems needlessly redundant. In the Friend app, the Classic and Aware settings/controls are listed separately, which also seems needlessly confusing and redundant. Since their functions are linked, it seems to me that the functions of both ought to be combined once both devices are installed, instead of trying to remember which settings are listed under which device within the app.

Why didn't Blueair simply build an air monitor into the Classic? Because for optimum performance, it is suggested that the Aware be placed "with open air around it – preferably at the normal height level of your nose…the more open the placement, the better the air reading and Wi-Fi connection." You place the Classic differently, down on the floor, near a wall.

The air purifier will alert you when its filter is spent.Blueair


Other than its air purifying capabilities, which we'll get to in a moment, the most important aspect of the Classic's operation is fan noise. According to Blueair, the Classic 205 emits between 32 to 56 dB, which edges up toward the annoying range at its top speed; practically, while sitting on our sofa three feet away with the TV on, I couldn't hear the Classic 205, but could at its two higher speeds.

Because of the noise, I never used Automode, which always seemed to notch up the fan speed during dinner and prime time TV viewing. Instead, I used Night Mode to run the fan at the top speed when no one is in the living room.

The rest of the time, and outside of the rare occasion when the Aware LED turned orange – often for no discernable reason – leaving the Classic on its lowest speed seems to work just fine.

But does it work?

Being a cynical cuss, it seemed to me that the entire Blueair ecosystem seems to be a self-serving, self-fulfilling prophecy. The Air Monitor and the Friend app say my air is polluted, thereby necessitating the Classic. It's like an auto mechanic or an electrician or a plumber – or even a doctor – telling you you need expensive repairs, which may or may not be needed but certainly benefits the repair person.

Unlike these repair professionals, however, there's no way to get a second opinion for the Classic 205/Aware readings. You won't detect any changes in your indoor air – it won't smell any different, for instance. My only clue as to the Classic's efficacy is that I haven't gotten sick at home while I've had it, which also may be credited to the daily dose of Astragalus, an immune strengthening herb my doctor recommended to me early this year. But I digress.

For a year, I've searched in vain for an independent air monitor that tests for the same particles the Classic filters. Other than the Classic's now dirty filter (the Friend app says it won't need to be replaced for another three months), I could find no objective confirmation that my air is actually as polluted as indicated, or that the Blueair is solving the problem.

To help, Blueair sent me comparative measurements made by MiniWRAS (Wide Range Aerosol Spectrometer), a professional/research grade particle monitoring system. "Based on the results of these tests," Blueair notes, "the data shows the Aware monitor being within tolerance of ±(40%+5). This data shows the accuracy of unit designed for the home compared to a unit designed for laboratory environments."

Here's the comparative graph, FYI:

Chart that indicates the air monitoring ability of Aware.Blueair

Aware 1042: Data points of Aware within ±(40%+5) tolerance 28 out of a total of 33 (84.9%)

Aware 1003: Data points of Aware within ±(40%+5) tolerance 30 out of a total of 33 (90.5%)

To further substantiate its claims, Blueair notes that, "the Classic 205 is independently verified by the Association of Home Appliance Manufacturers (AHAM) for a Clean Air Delivery Rate (CADR) of dust/200 cfm, pollen/200 cfm, and smoke/180 cfm, ENERGY STAR rated, and tested by the California EPA Air Resources Board for ozone emissions."

So I contacted the AHAM about its Verifide program for air purifiers, and a spokesperson confirmed that the Classic 205's numbers were "well beyond" the standard organization's minimums for filtering dust, pollen and smoke, especially since the AHAM minimums assume "one room air exchange per hour" – the Classic claims five such room air exchanges an hour.

As far as the ozone emission assertion, Melanie Turner, Public Information Officer for the California Air Resources Board, told me that "the California Air Resources Board did not test the Blueair 205, but rather Blueair had the product tested for ozone by one of the approved laboratories as required under CARB's regulation. The Blueair 205 passed – [it] emits less than 50 ppb (parts per billion) ozone – thus it was able to be listed as certified by CARB and sold in California. Regarding ozone, some air cleaners emit ozone, either intentionally at high levels or as a by-product of their technology – usually at low levels in this latter case."

In other words, that whole ozone business is a misdirection; all Blueair is saying is that the Classic 205 won't emit harmful ozone, not that it eliminates it. It's essentially as if a food product label noted that it isn't made with poison.

More convincing is a link on the Blueair web site to results of independent tests run by the Stockholm-based Testfakta, which seems to be the Nordic version of Consumer Reports, in which the larger Classic 405 was the highest-rated among 12 leading European air purifiers.

So between the the MiniWRAS comparison, AHAM's Verifide certification and the Testfakta tests, it seems the Classic performs as advertised, even if there's no way you'd be able to obviously sense its performance for yourself.


If you're worried about the health of all in a home filled with asthma or allergy sufferers, kids, pets, lots of cooking maybe even smokers, an air purifier will make you breathe easier, figuratively and literally. Even though I had no way to confirm its claims, the Blueair Classic 205 seems to have kept me healthier, and other folks seem to confirm that the Classic series is the best of the smart air purifying bunch.

Pros: App lets you monitor, tVOC, CO2, particulate matter, weather, temperature, has night mode, a child lock and claims to recycle the air is a room five times an hour.

Cons: Can veer towards loud side on higher settings and can't verify ozone claims.

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