Hi @mattkoch. The WaterUseEquipment class inherits from the more general SpaceItem class.

... which offers methods like space, setSpace and resetSpace. Although classes have had functionality expanded over the years, the inheritance diagram remains +/- the same. In Ruby, this would look something like:

require 'openstudio'
model = OpenStudio::Model::Model.new
space = OpenStudio::Model::Space.new(model)
wue_def = OpenStudio::Model::WaterUseEquipmentDefinition.new(model)
equip = OpenStudio::Model::WaterUseEquipment.new(wue_def)
equip.setSpace(space)