The Blue Pure 311 Auto air purifier is a top pick in Wirecutter's 'The Best Air Purifier 2020' for "Delivering exceptional performance in an attractive form".~ The Blue Pure 311 Auto take a simple approach to air quality management with an integrated particle sensor, Auto mode setting, and LED air quality display. The ENERGY STAR~ certified air purifier delivers high performance with one-button control and customizable pre-filter colors in a lightweight, compact package. Independently evaluated and third-party tested for performance as part of the AHAM Verifide~ Program for room air cleaners, this air purifier has a Clean Air Delivery Rate (CADR) of 250 cfm for fine smoke particles, 250 cfm for pollen particles, and 244 cfm for dust particles. Recommended for medium rooms like a master bedroom, living room, or playroom with a 360~ air intake to completely filter room air about every 12.5 minutes~ (approx. 4.8x an hour at 388 ft~) on the highest speed.~ The 3-step combination particle + carbon filter works with Blueair's HEPASilent~ filtration technology to remove 99.97% of airborne particles down to 0.1 microns, like pollen, dust, pet dander, mold, bacteria, viruses~ and more. An additional layer of activated carbon traps light household odors.~ Blue Pure 311 Auto quietly cleans the air with less noise than a soft whisper~ on low (23 dB) and up to a normal conversation on high (53 dB) ~ while using less energy than a light bulb (3-35 W) on all speeds.~ The one-touch enabled Auto mode is designed to help you maintain a comfortable environment. When enabled, the setting automatically adjusts to real-time conditions reported by the integrated particle sensor. Stay up to date on your air quality with the LED display; it changes color to indicate good, moderate, or poor. Change color in seconds with five fabric pre-filter options inspired by Scandinavian nature. The fabric material of the pre-filter catches larger particles and extends the life of the primary filter. Plus, a hidden compartment in the fabric pre-filter keeps the power cord hidden out of sight. Vacuum the fabric or toss it in the washing machine whenever it needs cleaning. Pre-filter in Arctic Trail (gray) included; Additional colors available for purchase. At Blueair, our Swedish heritage inspires sustainability and quality at the heart of everything we do. All Blueair purifiers are AHAM Verifide for Clean Air Delivery Rate (CADR) and given a recommended room size, certified by ENERGY STAR for energy efficiency and the California EPA Air Resources Board (CARB) for safe ozone emissions. ~From Wirecutter. ~2020 Wirecutter, Inc. All rights reserved. Used under license. ~Air Changes per Hour (ACH) calculation is a product of recommended room size & average ceiling height over pCADR ~According to ANSI/AHAM AC-1 recommended room size ~This air purifier not been tested against & Blueair does not claim to capture, remove, or kill SARS-COV-2 (COVID19) ~Based on GB/T18801-2015 test standards for the removal of formaldehyde & VOC ~Sound pressure according to GB/T18801 & GB4214.1 ~Tested according to GB/T18801-2015 standard. "Light bulb" defined as an LED light bulb with 40 W energy consumption.