Once, while hiking atop an 800-year-old volcano in Iceland, with a stiff wind blowing from the north Atlantic, I breathed in more fresh air than I thought I might have ever needed for the rest of my life. That might be an overstatement, but conversely, when you are breathing air that’s less than ideal and need a helpful hand in picking the putrid particles from the pleasant, you can rely on the Blue Pure 511i Max to help sort out the sordid air you may be breathing.
How does this Swedish design firm achieve this? Surprisingly, not by capturing and ladling breathy ABBA harmonies throughout the room. Nope, it’s more like the magic of HEPASilent™ filtering employed at customer-selected speeds via the simple on-unit buttons, or via the available app. In addition to the three manual speeds, there are automatic and night modes, where the night mode drops the fan speed to a quiet minimum sound and an appropriately dim lighting scheme. The automatic mode seeks to filter out particles in the air to a level of PM 2.5 (Particulate matter of 2.5 microns in size), and is measured by an on-board particle sensor. As the air is being cleaned, the particle sensor measures and reports the perceived air quality to the app which shows five differently-colored display illustrations keyed to the air quality. Keep in mind that this unit was designed for smaller, closed rooms that are less than 193 square feet, or about 14 feet by 14 feet. The app also keeps track of the unit’s efforts in cleaning the air as well as use and filter condition based on time used and air quality filtered. Overall, a useful and well-developed app.
I have to admit that I house a degree of skepticism towards the efficiency of products in this market segment. I don’t quite understand how a relatively slow-moving fan barely moving air can be expected to clean all the air in a room. It’s rated at 4.8 air changes per hour, which must be in the fastest speed, but it’s hard to believe that the slower speeds would do very much, other than clean the air in a very small and local subset of the room. The proof of effectiveness is, of course, going to be lodged in the filter and prefilter over time.
This Blueair model is designed to capture smaller particles that pertain to elements like smell, smoke, pollen, as well as regular dust particles. The filtering of particulates of PM 2.5 size mentioned in their literature, is achieved by the use of electrostatic, mechanical and/or carbon filtering. There are three different filters that work with this unit. The included one, is the Particle and Carbon, and optionally available are the Allergenblock and the Smokeblock, which are self-evident.
Some of the other features that I like about this product are the aesthetic design choices, the easy filter cleaning and/or replacement and the intuitive and well-designed controls. In addition, the outer fabric covering of the air cleaner serves double-duty as a washable pre-filter, as well as a cosmetic chameleon, due to its availability in numerous “Scandinavian inspired” colors at relatively low cost. There is also a subscription plan available that will supply you with your desired filter types at a reduced-price rate and at apt user-defined intervals. I’m also a big fan of included, quality, paper manuals for products, that have clear illustrations and readable type, as they have done here. The fan noise is, of course, proportional to the fan speed, but is quite reasonably quiet at from 19 to 48 dB per Blueair’s specification. If you need a white noise generator to help you get to sleep, this could be a fairly quiet one at the faster speeds.
On the cons side of the equation, I’m not a big fan of permanently attaching a wall wart’s cord to the body of a unit. If there are issues with the power supply, it seems like you’re just creating more work or cost by binding them together, not to mention making it a little more awkward to move.
I like this product for the performance, price, features and simplicity. In my use of the product, I did not have any particular air quality issues that needed to be addressed, and my daughter’s cat moved out just as this device arrived, so I was unable to test this in the cat’s sleeping area to see if it helped. However, used in our bedroom, it seems to be doing just fine, as I perceive no noticeable air quality issues and a bonus reduction of dust on furniture. As I have no way to verify empirical data on this unit in a short period of time, I will just have to trust that the specifications were drawn from reliable testing and adequate design. If this model doesn’t seem to fit your room size or other air handling requirements, there are many models in the Blueair lineup that probably will. Seems like a good company from previous product’s awards and all I’ve read.

This was my first time trying a Blueair branded air purifier, and I was pleasantly surprised!

It came fully assembled, but I actually decided to disassemble it to get a better idea of how to access the filter and how the device opens and latches (I would encourage anybody buying this product to do so, to get a better idea of safe ways to carry the product, and of what the removable and washable parts are). Reviewing the quick start manual is a must, to understand how to connect this product to wifi, although once you look over the guide, you will find that the product is very simple to use and more intuitive than one might think just from looking at it.

The Blueair app was easy to locate in the App store, and was fairly simple to use for connecting the device to wifi (note that you must use a bluetooth connection before you can get to the wifi only connection; you can then disconnect from bluetooth). The primary criticism that I have is for the first page of the App, as I was confused about why I had to enter an "outside" location when there is an indoor location option that forces you to enter your local area information anyways. The actual app options beyond the first page are simple and intuitive to follow, showing air quality, filter life, LED brightness slide bar, night settings, a child lock option, and event the ability to auto-operate the device on a schedule of your choosing.

This purifier gets very good air flow, and the lower setting is fairly quiet. I found the LED lights to be a bit distracting at night even on their lowest settings, so I ended up placing the device in a way where the lights would not disturb me in the evening ( am using it in my bedroom).

I would recommend this air purifier to anyone in the market for one, and have now added Blueair to my listing of preferred purifier brands. While I usually do not like devices that are solely dependent on an App, I did find the App to be very convenient to use with this Purifier, and I enjoy getting air quality and filter quality details digitally alongside having the exterior light to identify filter replacement or poor air quality. I will definitely consider Blueair branded purifiers when looking for my next one, assuming this one last long (I've only had it for about a week or so), and that the filter is as easy to replace as it seems it would be.

I cannot recommend this air purifier. I had read good things about Blueair air purifiers and when we wanted to add another purifier to our house I thought I would give them a try.

The cons:
I chose this one specifically because it has integrated air quality sensors that the unit purportedly uses to adjust the fan speed when it detects more particulate in the air.

This was not my experience. When our house smelled like a campfire due to a neighbor's fire pit, this unit kept chugging along showing a blue light, indicating the cleanest air quality. I was surprised so tried to test it and put it right in an open window nearest the smoke outdoors, and still it showed blue.

I contacted customer service and they instructed me to clean the air sensors, reset the machine, then use a candle to blow smoke directly at the sensors to test them. I tried the test before and after the other cleaning and resetting, and both times it 'worked'. A few days later we had a smoky house again and it again didn't detect it. I also burned something on the stove (not in the same room, but the air flow in our house pulls kitchen smells to the room this was in, and I could smell the burnt food by the machine) and it didn't detect that either. I only had it detect poor air quality once, when I was cutting drywall with a power tool in the next room.

The pros:
It is a very compact machine so can fit on a side table, dresser, nightstand, etc. It is also very light, so it could easily be moved from room to room if you only want to buy one and have it in the living room/common area during the day and the bedroom at night.

I like the idea of the washable pre-filter to hopefully prolong the life of the more expensive filter inside, this seems especially beneficial with pets. I did not have this machine long enough to see how well this would work or if it would hold up well to repeated washing.

The controls are fairly intuitive, and I like the ability to dim the lights rather than just having an on or off setting.

All-in-all, I wouldn't rule out a Blueair air purifier, but I would NOT pay extra for their air quality sensors as they don't seem to work.

I have an old house and air cleaners are a necessity for us to cut down on all the old house cruft floating around. I currently use 5 of same type, that share filters. Filter costs are out of control for this brand, so the Blueair and it’s inexpensive filters jumped out as something to try.

The Blueair 511i is sized just for what they claim, a small bedroom, any room much bigger or experiencing a lot of air moving through would be quite the challenge for this little guy without running the fan at a high speed. The plastic is white and the bottom is medium gray, which I think might have a hard time clashing with any bedroom. I understand the company is called Blueair, but that doesn't mean putting a blazing blue LED on a unit specifically marketed for a small bedroom is a bad idea, and it can be switched off with the app or by using the controls on top to set night mode. In the dark, there is no dark, that light lights up the whole bedroom. I went ahead and added a LightDim sticker to it, which makes a big difference.

The fan is not noisy until it gets over a half setting and I would say there is no reasonable person who would tolerate the fan on full for more than a few minutes, it is silly loud. It also sounds like a direct drive brushless motor in there, so there is the faintest of pulsing sounds at lower speeds, but I’m the only one that hears it, so that’s good.

The app is wonderfully simple, just about as simple as the controls on top, which consist of 2 buttons, the app has it’s AQI at the top and you get some configuration of the different speeds, timers and lighting. It doesn’t do much else (what else is there to do?). It seems it might be nice if I had guests arriving and I was somewhere else, I could have this in the guest room and turn it on for folks arriving even when I’m not around. The AQI on my unit did not change-at all- for a week of running, “Is this working?”, so I moved it to another room with a drafty sliding door and it changed, so it does work, I just got lucky and found the clean air, I guess.

The fabric covering around the bottom 2/3 of the unit is a washable pre-filter, catching larger dust and fur and other stuff that would quickly clog the finer filters. This is a great idea, a bit of “why don’t all of them have that?” sort of thing. Not only does it cut down on filter costs, which is nice, but it also cuts down on stuff I’m throwing away.

Overall, the Blueair 511i Max is a great addition to our house and I look forward to many years of care-free use!