I've been looking for a new air purifier for almost a year now, doing research here and there trying to find a unit that meets all the requirments I'm looking for. I need a unit that's for a larger room, has an auto feature, has good priced replacement filters, and looks good to match my home decor. A recent 80,000 acre fire hastened my research due to the thick blanket of smoke that blanket the area (and still is) every morning. With all things considered, the Winix 5500-2 met all my requiements.The unit arrived promptly and unpackaging was an ease. I literally had it set up ans running in about 5 minutes. The body is a hard, matte black plastic that feels sturdy and durable. The front panel is easy to remove, and secures to the unit via a clever magnetic clasp that is secure, yet simple to remove to access your prefilter for bi weekly cleaning and hepa/carbon filter replacement. There are 3 filters in total, and they fit snugly inside the filter chamber, amd ate secured in with the prefilter that snaps firmly into place.The control panel at the top is intuituve and user friendly. The buttons are clearly marked and visual ques explain what each button does taking out any guesswork as to what they do. A stylish indicator light bar runs along the bottom of the control panel indicating the level of air cleanliness with a 3 color scheme...green for clean, orange for okay, and red for bad. You can manually run the machine on 4 fan settings, or choose auto mode and let the machine choose the settings based on the data colected from the sensor. This means hands off operation. There's a night mode that will set the fan to its lowest setting to cut down on noise, and also dim all lights on the panel. This night mode will set automatically if you have the auto mode set on the unit, a light sensor will detect (or not detect) any light in the room and go into night mode. A filter change indicator light also is on the control panel. According to what i've researched, the hepa filter should last approx 1 year. It also comes with a remote control with a battery preinstalled. I dont plan on using it, but if that's your thing, it's there.This is the quietest air purifier I've ever owned. On level 1, it's almost undetectable, and even on level 4 turbo mode, it's no louder than a standing floor fan on high. This was a very pleasant surprise.It cleans the air well. I'm currently using it in my 350 sq ft bedroom. I don't have the equipment to test it, but per their website I should be getting at least 4 air changes per hour which is the amount of air exchanges you need for allergies and serious air purification. I've had no smoke smell AT ALL in the bedroom when I run this with the door shut to the rest of the home and it was initially startling to walk from the bedroom into the rest of the home after the first night of using it.This unit has more than exceeded my expecations ans meets all the things I was looking for in an air purifier. I plan on purchasing 2 more of these when money permits for my combined kitchen/dining/living room area that totals 700 sq ft. I can place these at opposite sides of the area and get more than ample coverage. I would highly reccomend this unit. For the price and the feature list, this just can't be beat. The cost is low, the replacement filters don't cost an arm and a leg, it covers a large area, and you get a lot of features.09/28/20192 years later and this machine is STILL going strong. Besides the occasional vacuuming of the pre filter and the yearly filter changes, I've had this guy quietly working away in the house keeping my air clean. Can definitely say at this point that it's a durable machine!08/20/20203 years later and still working! I'm only posting this update because I find myself in ANOTHER horrible fire season for California, and I'm in a zone getting insane amounts of smoke. Besides regular cleanings on the pre filter, and my yearly change out of the hepa and carbon filter, not much else to report. I really hadnt expected this thing to last this long as I run it 24/7, often on its highest setting to get maximum results. I own 2 now, I bought another one last year to get more coverage throughout the house. I would highly recommend this until to anyone.01/03/2022I was buying a new filter today on here and remembered that I actually had a review for this product. I've owned this air purifier for 5 years now. I just added 2 more photos (should be the last 2 in my string of pictures) just to show that I STILL own this device. 5 years of literal CONSTANT USE. I've had it set on the 3rd setting, just 1 below it's highest setting, for nearly this entire time. I have absolute confidence stating that this is a solid piece of machinery. I'm actually shocked that this guy hasn't given up on me yet! If you're worried about durability, at least in my case, yes, this is a very durable air purifier. Winix created a home run product with this one. I think that this may be my FINAL update on the product (unless of course it survives for 10 years, in which case I may throw a party for the thing!)***I also want to add to those who say this device produces harmful amounts of ozone. That's simply not true. You can go to the California Air Resource Board, specifically to the section under California Certified Air Cleaning Devices. This will show you a list of air purifiers that have been tested by the state and produce under 0.050 ppm of ozone. This device, and all others from Winix, are on the list. That means that this device is at, or below, the levels indicated as safe. Make sure when reading reviews you guys do your own follow up research on an item. It's insane the amount of bad information that's out there! Dont take anyones word, look up what they claim!***