Abstract: Methods, apparatus, and systems are provided for measuring the supply of a consumable product to a facility over time and analyzing the measurements to determine the consumption or supply of the product by one or more loads and/or sources in the facility, and to determine induced and residual heat flow through the facility's envelope. Various aspects compare the measured supply of the consumable product to a database of consumption signatures. Operating conditions and facility characteristics may be further considered in determining a particular user's access of the consumable product. Thermal resistance factors of the building may be determined, which are based on the induced and residual heat flow through the facility. Finally, one or more signatures of a building system are analyzed to determine a building's overall efficiency, including determining a controllable load of a building and/or determining an efficient start time for one or more building systems.