Humidifiers have evolved over the years. The drum style with crusty pads and slimy water pans are a thing of the past. Todays humidifiers feature a flow thru design where the water tricles down a metal mesh with the excess higher mineral content water going down the drain. The result is cleaner, low maintenance humidifiers that are no longer a breeding ground for bacteria. Carrier produces a complete line of flow through, fan assisted, and steam humidifiers.