Abstract: Illustrative embodiments of the present invention are directed to a method and system for disaggregating climate control energy use from non-climate control energy use for a building. The method includes receiving a series of building energy use values and corresponding outdoor temperature values for a time period. Each of the energy use values and outdoor temperature values is associated with a time interval. The method further includes determining a series of temperature difference values for the time period based on a difference in temperature between a predetermined baseline temperature and each of the outdoor temperature values. A regression analysis is used to determine a climate control coefficient and a non-climate control coefficient from the energy use values and temperature difference values. The climate control coefficient and/or the non-climate control coefficient is used to determine climate control energy use and/or non-climate control energy use for the building.