Blueair Blue Signature air purifier review: Powerful and elegant

We are big fans of Blueair air purifiers here at Live Science. Whether it is the compact, budget-friendly Blue Pure 411i Max or the premium Classic Pro CP7i, appliances from this Swedish brand tend to win us over with their quiet performance, user-friendly design and well-thought-out smart features. We frequently feature them in our guides to the best air purifiers and best air purifiers for allergies. When we were offered a chance to test the new model, the Blueair Blue Signature, we did not think twice about it. This air purifier is a specs powerhouse, and has huge potential to make its way into our recommended round-ups.

The Blueair Blue Signature is suitable for spaces up to 3,385 square feet (314 square meters), straight away making it one of the most powerful air purifiers we have ever tested. Moreover, it features seven stages of air filtration, including patent-pending OdorFence Technology, which, according to the brand, removes up to 10 times more pesky smells than traditional carbon-based filters.

This air purifier also comes with a motion-activated display, a washable fabric pre-filter and a dedicated app. Most notably, the Blueair Blue Signature looks exceptionally stylish and can double as a small table. This air purifier could compete with some of the best appliances from market-leading brands like Dyson and Levoit, and we were keen to put it through its paces.

Blueair Blue Signature air purifier review

Blueair Blue Signature: Design

• Stylish, portable design
• Doubles as a small table
• Lacks some durability

The price of the Blueair Blue Signature depends on your chosen design. The basic version of this air purifier costs $449.99; it features no leg base and comes in two colors only, grey Nordic Fog and black Midnight. Then there are the add-ons: you can get fabric pre-filters in different colors, such as cream, beige, dark blue or green, each at $24.99, as well as a stylish wooden leg base for $79.99, and a grippy chrome ring base for $99.99. Our testing unit came with a dark blue cover and no accessories, a combination that would typically cost $474.98 — not the most expensive air purifier we tested, sure, but still at the more expensive end of the spectrum.

It does feel quite premium, though. Weighing just 13.2 pounds (6 kilograms) and measuring only 17.2 inches (43.6 centimeters) in height, the Blueair Blue Signature is surprisingly light and compact for an appliance of its air-cleaning capabilities. It can be easily moved around the house, even though it does not have any handles or ridges that would increase its portability.

It is also a pleasure to look at. We would even go as far as to say that it is one of the most elegant air purifiers we have tested. We particularly liked that the washable fabric pre-filter, with its lovely texture and ultra-elegant navy shade, made our Blueair Blue Signature look more like a piece of furniture than a domestic appliance. The light illuminations from underneath the control panel also scored highly in our books. They flow slowly from left to right and change color to indicate any drops and spikes in air quality, but we did not find them too bright or otherwise disruptive. The Blueair Blue Signature was a talking point in our home, and we bet it would be in yours, too.

Interestingly, this air purifier can serve as a small table. That said, we would not treat the Blue Signature as a full-blown table-purifier (like in the case of a SwitchBot Air Purifier Table, for example). Its top surface is made of light plastic, making it relatively fragile, plus it is relatively small. There is some risk of damage to the air purifier if, for example, there is too much weight placed on top of it. As such, the Blueair Blue Signature is best used for storing remote controls, books and other small, light items. We liked that — that design tweak proved to be very handy.

On the other hand, we were not too convinced about the durability of the Blueair Blue Signature. Starting from the external fabric pre-filters: they do a great job of catching dust, hair and other big airborne particles, true, but they also require frequent washing and drying, and it is quite easy to rip them, too. Peeling the filter out of the appliance and putting it back on can also be annoyingly laborious. It is also worth mentioning that fabric pre-filters can attract curious paws: if you are a cat owner, you may need to consider that before investing in the Blueair Blue Signature.

The rather steep price of replacement filters is another downside — they cost $99 and need to be changed every three to nine months, depending on the usage. This means they are nearly twice as expensive as most other filter replacements we have used before.

Blueair Blue Signature: Features

• Auto mode, Night mode and four fan speeds
• Real-time and historical air quality measurements
• Patent-pending OdorFence technology

The Blueair Blue Signature has some impressive air-cleaning specs. To start with, it offers seven stages of filtration, when most air purifiers have just two or three.

These include a certified HEPA filter capable of capturing up to 99.97% of airborne particles as small as 0.1 microns, and an activated carbon filter for absorbing gases and odors. There is also the patent-pending OdorFence Technology — an enzymatic solution that helps remove gases by breaking them down rather than trapping them in the appliance. According to Blueair, this technology is up to 10 times more effective at combating unwanted smells than carbon filters. It is a bold claim, sure, but it could well be true given how quickly enzymes work. That said, we could not find any published studies that could further explain how this technology works or how effective it is.

The Blueair Blue Signature offers a good range of intensity settings. This air purifier comes with four manually adjusted fan speeds, an auto mode (when the fan speed gets automatically adjusted based on the readings from the built-in air quality sensor), a night mode (auto mode, but with fans operating at slower speeds) and an eco mode (auto mode with minimal energy consumption). In the app, the Blue Signature can also be scheduled to switch on and off automatically at preferred times.

The app is also where you can access its detailed measurements of air quality. Most air purifiers either use a single AQI (air quality indicator) for a general overview of air pollution, or they focus on tracking airborne particles of a specific size — usually, those measuring 2.5 microns or less (PM2.5). The Blueair Blue Signature, on the other hand, also measures PM1 (airborne particles measuring less than 1 micron), and PM10 (those larger than 10 microns). Moreover, it provides both real-time and historical measurements. In the app, you can view graphs depicting air quality changes on a daily, weekly and monthly basis, making it easy to identify trends in air pollution over time.

Lastly, the Blueair Blue Signature features a child lock and an air filter life indicator, and its brightness display settings can be adjusted in the app.

Blueair Blue Signature: Performance

• Great air-cleaning performance
• Whisper-quiet and unobtrusive
• Effective at removing household odors

The performance of the Blueair Blue Signature exceeded our expectations. This air purifier seemed to do exactly what it promised — it made a massive difference to the air quality in our home, quickly and efficiently removing various airborne pollutants, and was superb at removing odors. Indeed, it did seem to capture bad smells better than most other air purifiers we tested. All that, and it was also very quiet and did not use much electricity. No complaints.

According to Blueair, this air purifier can purify air once every 12.5 minutes in spaces up to 705 square feet (65 sq m), and once every hour in spaces of up to 3,385 square feet (314 sq m)— and these claims are in line with its CADR ratings. These independent metrics, measured in cubic feet per minute (CFM), indicate how quickly an appliance can clean the air in a given space. For the Blueair Blue Signature, CADR ratings are as follows: 455 CFM for smoke, 450 CFM for pollen and 434 CFM for dust.

While it may be tempting to use this air purifier in very large spaces — its CADR ratings are indeed indicative of huge processing power — we would recommend sticking with the brand guidelines and keeping the Blue Signature in rooms no bigger than 705 square feet. One change of air per hour may not be enough to achieve the best results, especially for people with airborne allergies and respiratory conditions, and most air quality experts advise at least four changes per hour. Still, 705 square feet is big enough to cover most typical bedrooms, studies and living rooms.

We performed our air quality tests in our living room, the biggest in our house. We used our trusted Perfect Prime air particle monitor to measure air quality readings before and after running the Blueair Blue Signature in several different circumstances.

We started with an ambient test. We aired out the room, placed the air purifier inside, closed the door and windows, then ran it on Auto mode for 30 minutes. After the first 15 minutes, we noted a 68% reduction in particles measuring 0.3 microns, and a 79% drop in air pollutants measuring 2.5 microns. After another 15 minutes, these values increased to 89% and 99%, respectively. Given that our baseline air quality was already relatively good on that day, these numbers are quite impressive.

Next, we tested the Blueair Blue Signature against heavier air pollution. We started by burning 10 matches and then running it on Auto mode for 30 minutes. After the first 15 minutes, 0.3-micron particles were reduced by 94%, 2.5-micron pollutants dropped by 98% and the largest 10-micron particles decreased by 98.8%. After another 15 minutes, these values increased to 99.9%, 99.9% and 100%, respectively. When we repeated this test at its highest fan speed, we ended up with better air quality than we started with. We got similar great results when we burned five incense sticks and ran the air purifier to clean up the smoke. All in all, the air-cleaning performance is exceptionally good.

The cherry on top? The Blueair Blue Signature is very quiet, exactly as the brand promised. When we measured how loud this air purifier was with a Sound Meter decibel-counting app, its noise levels ranged from 20 decibels (dB) on the lowest setting (equivalent to a whisper), to 55 dB on the highest fan speed (as loud as the sounds you would hear in a library). It can be a great bedroom air purifier — as long as you dim the lights on the control panel, that is.

Blueair Blue Signature: User reviews

At the time of writing this review, both Amazon and Blueair customers gave the Blueair Blue Signature a stellar rating of 4.8 out of 5 stars. This air purifier was almost universally praised for its stylish design, whisper-quiet operation and superb air-cleaning performance, with many buyers reporting that it had a pivotal role in helping them improve their allergy symptoms.

One happy buyer said: "I honestly never thought about buying an air purifier, even though both my kids and I suffer from allergies. I just didn’t think it would make a big difference... until I tried this one from Blue Air – and wow, was I wrong! The device is small, discreet, and has a modern design that fits beautifully with my home decor (I love that it comes in different color options too!). [...] Since we started using it, I’ve noticed a significant improvement in the air quality and especially in our allergy symptoms. Another big plus: it’s very quiet. I can leave it in the kids’ room at night without any disturbance. If you have children, deal with allergies, or simply want to breathe cleaner air, I highly recommend this product. It’s been worth every penny!"

Negative comments, though few and far between, often revolved around individual faulty units. Some users also criticized the relatively high price of the Blueair Blue Signature.

Should you buy the Blueair Blue Signature?

✅ Buy it if: You want a good-looking, high-performing air purifier for large spaces. The Blueair Blue Signature is quiet, easy to use and exceptionally good at removing odors and various airborne pollutants, and its sleek design will fit in with even the most stylish interiors.

❌ Do not buy it if: You are looking for something that is less maintenance-heavy and more budget-friendly. There is a lot to like about the Blueair Blue Signature, but it is hard to deny its relatively high price or the hassle involved in cleaning and changing its fabric pre-filter.

If the Blueair Blue Signature is not for you?

If you are looking for something smaller and more affordable than the Blueair Blue Signature, consider the BlueAir Blue Pure 411i Max. Both of these air purifiers are quiet, smart-enabled and efficient at cleaning the air, and both look relatively similar. However, the 411i Max is better suited for spaces up to 526 square feet (49 sq m), and costs just $169.99.

If you like the idea of a table air purifier, or are an owner of a very curious cat, we would recommend the SwitchBot Table Air Purifier instead. This quirky appliance combines a wide, waterproof tabletop, wireless phone charging, fragrance diffuser and stacks of pet-friendly features, and it did a good job in our air-cleaning tests — but costs less than $200.

Looking for something even more artistic and unique? Then you can't go wrong with the RabbitAir A3. This premium smart air purifier comes in more than 10 beautiful colorways ranging from classic white to famous paintings and floral patterns, so you are bound to find something that fits your aesthetic. The only caveat? It costs nearly twice as much as the Blueair Blue Signature.

Blueair Blue Signature: How we tested

We spent nearly two months testing the Blueair Blue Signature air purifier, looking at its design, features, day-to-day performance, connectivity with third-party devices, ease of use and value for money. We also measured its noise levels using a Sound Meter decibel-counting app, and checked the cost of its add-ons and air filter replacements.

Next, we assessed the air-cleaning performance of the Blueair Blue Signature by conducting a series of air quality tests using a Perfect Prime air particle monitor. This industry-grade device detects pollutants as small as 0.3 microns. We started with an ambient test, where we ran the air purifier on its Auto mode for 15 and 30 minutes in an enclosed, medium-sized room, and recorded the change in air quality over time.

Finally, we performed several smoke tests. We burned matches and incense sticks to simulate severe pollution, then measured how quickly the Blueair Blue Signature can remove the smoke. For each scenario, we recorded the air quality before and after running the purifier for 15 and 30 minutes on different settings.