Welcome to the Home Energy Saver Multifamily API portal

The Multifamily API uses a modified version of the Home Energy Saver calculation methodology to provide energy estimates for buildings with more than one unit.

Developed jointly by Lawrence Berkeley National Laboratory (LBNL) and the Oak Ridge National Laboratory (ORNL), the Multifamily API was originally designed to provide the energy calculations for ORNL's MulTEA tool, but is also available to interested third-party developers.

The Multifamily API is presently able to model building with up to 5 stories, and can model a wider range of space types than can the HES single-family products, including hallway, plenum, and underground spaces.

Additional Multifamily API documentation is located on the HES Engineering Documentation site.