Recognizing that air purification appliances are most effective when operating constantly, Blueair Inc. (Chicago, IL, U.S) designed its Model 402 indoor air purifier to be more energy efficient by increasing efficiency by more than 30 percent. The unit is said to require less electricity than a light bulb.
Noise levels are also reduced, down to 51 dB at high speed and 27 dB at low speed; and, according to Blueair, the low speed noise level is about the same as a personal computer. Quiet operation is achieved by using a combination of mechanical and electrostatic filtration methods in the patented HEPASilent™ system. Because air flows more freely through the system, the company says, a more-powerful, noisier fan is not needed. The housing is constructed of steel, which Blueair says muffles sound better than a plastic housing.
To create a more environmentally friendly product, Blueair says it did away with standard triclosan-coated paper or glass filter fibers, which can harm the environment when released into the waste stream. Instead, the company explains, it uses a safer, nontoxic polypropylene. The water-resistant nature of polypropylene is designed to make the filters inherently resistant to contamination from bacteria, viruses, and mold, without chemical additives or washes. The company also uses a special powder coat finish that is said to produce no chemical outgassing.