Model 55UD Under Duct Flow-Thru Humidifier Minimal Electricity Water Efficiency


Model 86UD High-Capacity Under Duct Drum Humidifier Minimal ElectricityMinimal Water A Green Choice


Skuttle Under Duct Humidifiers are real workhorses that perform well on heat pumps and high-efficiency heating systems. In fact, they are superior to plenum-mount flow-thrus on today’s 90-plus furnaces.

Both the Flow-Thru and Drum Under Duct units handle more air volume than their plenum-mount counterparts because air flows directly through the ductwork rather than through a 6 in. (15.24 cm) bypass tube.

With normal maintenance, they cause no airflow resistance. The humidifiers’ efficient design actually increases airflow around the evaporator pads. The unique mounting frames allow fast, simple removal from the duct for easy cleaning and servicing.

Environmental Facts

Because Model 55UD employs the flow-through principle of humidification, it uses more water than other types of humidifiers. However, Skuttle engineers have reduced water consumption to the minimum necessary for effective humidification. Electrical consumption is minimal—about the same as a 25-watt light bulb.

Model 86UD, like plenum-mount drums, uses minimal water and electricity, making it among the most economical and ecologically friendly humidifiers to operate.

Flow-Thru and Drum Humidifiers do not produce harmful contaminants, nor do they release them into the air.


For Model 55-UD refer to the Flow-Thru Humidifiers page. For Model 86-UD, refer to the Drum Humidifiers page. Both units, along with their connecting water valves, must be turned OFF at the end of each heating season.

Download Owner’s Manual for both models.

Visit our Skuttle Parts online store to see parts diagrams and order replacement parts.

Minimal Electricity= Uses minimal electricity

Water Efficiency = Uses water efficiently

Minimal Water = Uses minimal water

A Green Choice = Most environmentally friendly