The Dyson Purifier Hot+Cool Gen1 purifying fan automatically senses, captures and traps pollutants to purify your whole room. It heats or cools the air, while removing 99.97% of particles as small as 0.3 microns. Tested In maximum setting for air projection, tested in Auto mode for purification coverage, tested for room heating per relevant Dyson method DTM961. Particle challenge by DEHS oil specified in EN1822 within a chamber specified in ASTM F3150. Tested in Max Mode for whole machine efficiency above 99.95%. Gas capture rates vary. Tested per ISO 29463.