Interior surfaces of an air handler unit are coated with a dense, non-porous material, which discourages and prohibits growth of mold, spores, algae, bacteria, germs, viruses and other organisms and microorganisms and allergens. Air is drawn into the air handler unit through a return duct and one or...http://www.google.es/patents/US5558158?utm_source=gb-gplus-sharePatente US5558158 - Hygienic air handler
