Located on the shore of Lake Johanna northwest of the main building, the powerhouse was an integral part of the original Nazareth Hall campus. Maginnis and Walsh designed the powerhouse at the same time as the Nazareth Hall building. The reinforced concrete structure, brick facing, limestone details, and gabled and hipped tile roofs of the powerhouse are similar to those of the main building.
Because of the relatively isolated location of Nazareth Hall at the time of construction, the powerhouse provided for heating and hot water on site. The building is set into the side of a slope with a high basement on the lake side. Projecting sections mark the entrances on both sides. A hipped-roof ell is placed on the east end at the upper level, which originally held laundry facilities and a workmen's dormitory. The powerhouse contained a coal bin built into the slope and high-pressure coal-fired boilers at the lower level. A tall chimney stack rises from the east end of the building.
Today the building continues to be used by Northwestern for its original heating function and also contains office space for the Physical Plant staff.