HPXML Data Dictionary

The data dictionary provides a standard vocabulary for describing terms related to buildings, energy consumption, and energy conservation measures. Each of the data elements defined in the dictionary can be transferred using the HPXML standard protocol.

The HPXML Data Dictionary (BPI-2200-S-2013 Standard for Home Performance-Related Data Collection) provides a standard vocabulary of data elements necessary to provide a general description of a whole house or single measure energy efficiency upgrade for reporting, rebate and basic quality assurance purposes. The Data Dictionary defines terms and formats related to the physical attributes and performance of buildings and measures, including:

  • Contractors
  • Customers
  • Buildings, building components and building systems
  • Energy conservation measures
  • Energy consumption
  • Energy savings (estimated and actual) 

The HPXML Data Dictionary also defines several standard datasets that can be used to describe specific use cases, for example, information collected during the audit and completion of a whole-house program. These datasets can be found here

Aligned with Industry Standards

HPXML is the most widely used implementation of Department of Energy’s Building Energy Data Exchange Specification (BEDES). BEDES is a taxonomy of terms, definitions, and field formats created to facilitate the exchange of information on building characteristics and energy use for the commercial, multifamily and residential industries.

HPXML is also aligned with the Real Estate Standards Organization's Data Dictionary, which standardizes terms used in Multiple Listing Services (MLS) nationwide so that data can be easily shared and understood in the real estate industry.

The benefit of having HPXML aligned with the RESO Data Dictionary is that home energy efficiency information, including score and labels, can be auto-populated into local MLS systems. Auto-population is an efficient way to introduce energy efficiency data into real estate transactions. 

There are several pilots underway to test the auto-population of MLS using HPXML, including the Northeast Energy Efficiency Partnerships' (NEEP) Home Energy Labeling Information Exchange (HELIX) and Build It Green's Green Registry. 

Continued Improvement

The HPXML Data Dictionary is designed to grow with the industry. If you have recommendations for adding new or changing existing data elements or enumerations create a new issue on the Github repository or send an email to hpxml@homeperformance.org with the following information.

Name: Create a name for the data element or enumeration you feel best describes the term.

Definition: Write a comprehensive definition of the data element and include references if necessary.

Data Type: Include your recommended data type and maximum field length.

Enumerations: If your recommended field is a pick-list, please include enumerations. Enumerations may also need a definition.

Justification: Please provide a reason the data element is important to your energy efficiency program or market.

Duplication: Review the dictionary thoroughly to ensure you are not duplicating an already existing data element or enumeration. Concepts can be expressed in a number of ways and rather than adding additional data elements or enumerations, we can use this recommendation to better define existing elements.