Honeywell HE225 Humidifier Pad with AgION Coating is a Humidifier Replacement Pad used with Honeywell HE220, HE225, Aprilaire Models 110, 220, 550, 558. The Humidifier Pad includes AgION Antimicrobial Humidifier Pad. Humidification Parts and Accessories Help maintain your customers' indoor humidity at its best. Remember, too little humidity can damage a home and its contents. To operate at peak efficiency, flow through humidifiers need new pads every season.