\label{sec:intro}
Performance and energy data generation in the built environment is rapidly growing \cite{Khan:2011ut}. Modern building controls and management systems are improving in their ability to acquire and store measured data as costs of these features are reduced. This phenomenon results in vast portfolios of collected data from heterogeneous buildings. Figure \ref{fig:hierarchy} illustrates a general example of various types of measured data from a conventional commercial building. Whole building performance is influenced by layers of complex measurement systems. Aggregated performance metrics or sensors are often measured or calculated at each level of this hierarchy in order to condense the exponential detailed sensor data downstream.