RECIRCULATING HUMIDIFIERS Lasko ™ Recirculating Humidifiers get their name from the continuous circulation of water through the unit. You might ask, "What does that do for me?" For one thing, it keeps the filter moist, self-cleaning it and increasing its useful life. For another, it increases the unit's efficiency, utilizing the entire filter surface for maximum, evaporative moisture output. It also eliminates standing water, helps to remove water contaminants, and won’t re-circulate airborne particles. You get cool, clean, invisible moisture, without white dust or over-humidification.