Aprilaire 400 Humidifier

Pros: Uses less water. Does not need to be drained to a sewer for normal operation.
Cons: Costs more, Requires twice the maintenance as the Aprilaire 500 or 600.

Aprilaire 400 is a bypass humidifier, as opposed to flow through. Unlike the Aprilaire 500 and 600 it's design reuses, rather than discharges, excess water. Water flows down through the evaporator pad as hot air passes through the pad. The excess water ...