The HPXML Transfer Standard (BPI-2100-S-2013 Standard for Home Performance-Related Data Transfer v.2.2.1) provides requirements for an extensible mark-up language (xml) data transfer protocol that can be used to transfer data related to energy efficiency upgrades between different software systems.
The transfer standard is the companion standard to the HPXML data dictionary. Each of the data elements defined in the data dictionary can be transferred using the standard xml transfer protocol.
The HPXML schema is hosted on Github. Members of the HPXML working group provide input into the development of the schema on an ongoing basis by creating and responding to new issues. The Github repository also hosts example HPXML files and the latest version of schema documentation.