Blueair 450E HepaSilent Digital Air-Purification System Award winning Swedish design, developed specifically for rooms up to 365 square feet in size Patented HEPASilent technology captures 99.97% of harmful particles down to 0.1 microns in size Clean Air Delivery Rate (CADR) of 240 cfm for smoke, dust, and pollen, with 5 air changes per hour Winner of the Excellent Swedish Design award and a permanent spot in Stockholm's National Museum Auto speed control automatically tests the air quality and adjusts speed accordingly