Why Open Standards Matter for Home Energy Efficiency

September 26, 2018
Julie Caracino, Home Performance Coalition



This is the first of a new monthly series that will showcase the benefits of HPXML in scaling the home energy efficiency industry by organizations that use the data standard – software companies, utility programs, government, and contractors. Every month, the blog will feature a new writer who will describe their organization or program’s experiences with HPXML, including both the technical and business aspects of HPXML adoption and use. The goal of this blog will be to help the residential energy efficiency industry understand the real world benefits of adopting HPXML for the distribution and/or consumption of residential building and energy performance data.

A Primer on HPXML

Data standards exist in many industries, including industries similar to our own. But the use of data standards is relatively new to residential energy efficiency. For example, the Environmental Protection Agency (EPA) creates data standards for their programs to promote the efficient sharing of environmental information among EPA, states, tribes, local governments, the private sector, and other information trading partners. Data standards also exist in the real estate industry to facilitate the population of home sale listings with high-quality data from multiple sources.

Like the use of data standards in other industries, data consistency, interoperability, and industry efficiency are key reasons behind the development and use of HPXML. Home Performance Extensible Markup Language, or HPXML, is a Building Performance Institute (BPI) data standard for the residential energy efficiency industry. It is comprised of two related data standards (together referred to as HPXML) that include a data dictionary, which standardizes the names, definitions, and data formats for terms used to describe a home’s energy efficiency features and performance, and a standard extensible markup language (XML) communication protocol that enables different software systems to exchange information and data defined in the dictionary at the click of a button. The industry uses HPXML to make data more meaningful and interoperable, and by extension, more accessible to the market actors that benefit from the use of residential building and performance data.

The Benefits of Open Data Standards

HPXML is an open data standard (as opposed to a proprietary standard) because it can be freely accessed, adopted, and approved upon. This is an important attribute of HPXML, so it’s worth spending some time discussing the benefits of open standards and what the use of open standards means for the residential energy efficiency industry, particularly for readers who may not be using HPXML or may be using a non-standard or internal data transfer protocol that is unique to one software or program.

The Home Performance Coalition (HPC) chairs the HPXML Working Group with oversight from the BPI Data and Modeling Standard Technical Committee. The working group has 59 member companies comprised of software developers, contractors, utilities, government, nonprofit organizations, and others that are using HPXML and invested in its development. Any person or organization may submit a request to change or enhance HPXML. These requests go through a review and approval process established by the BPI to ensure that decisions about the standards’ development are collaborative and consensus based, and that no one organization can gain a competitive advantage over its competitors.

Because people with diverse backgrounds and goals are invited to participate in the creation and use of HPXML, the standard, like other open standards, represents “the best solution” for our industry. Unlike closed standards that are typically developed by a limited number of people and controlled by one company, HPXML working group members provide feedback on HPXML that spurs innovation in the market.

Open standards also facilitate broader adoption because they eliminate one of the biggest barriers to adoption – the cost of obtaining and using the standard. They give everyone access to the standard’s definitions and protocols so that use of the standard does not require interpretation or transformation. This ensures the standard is implemented consistently and efficiently. In addition, because the definitions are freely available, open standards can be easily mapped to other open standards, or even to closed standards.

Using HPMXL to Scale the Home Energy Efficiency Industry

Open standards permeate almost every aspect of our life and are often a requirement for doing business. For example, the Wi-Fi you are connecting on is based on a series of wireless networking standards from the Wi-Fi Alliance. Bluetooth is also a wireless technology standard for exchanging data over short distances.

Bluetooth is managed by the Bluetooth Special Interest Group, which has more than 30,000 member companies in the areas of telecommunication, computing, networking, and consumer electronics. By adopting the open Bluetooth standard, competition and innovation have flourished in multiple markets. Similarly, when software companies adopt HPXML as the standard communication protocol to exchange data on residential buildings, measures, and energy performance, developers can shift resources away from moving data to focus on improving software usability and design. Program administrators no longer have to spend a lot of money building software from the ground up because software companies have already made the initial investment in HPXML and can compete based on the features they offer.

Since HPXML was first published in 2013, 16 software companies and open source data platforms (e.g., Standard Energy Efficiency Database) have adopted the standard, with more expected to be using HPXML by 2020. These software companies provide program management and energy modeling services to 13 residential energy efficiency programs and hundreds of contractors across the United States. Programs like Arizona Public Service have used HPXML to automate project review and approval processes, and open the software market for home performance contractors. Using a common data format is also helping to track and aggregate energy savings in states that deliver residential energy efficiency through multiple utility and non-utility (e.g., Pearl Home Certification, pay-for-performance models) programs.

Connection and transparency are crucial for innovation and building markets. If we expect to scale the residential energy efficiency industry, utilities, contractors, government, and other private sector actors will need to be connected to each other and to stakeholders in other industries such as the financial and real estate markets. The market will also need to have access to high quality, low cost data on residential buildings, energy conservation measures, and energy performance.

In the upcoming months, this blog will help demonstrate the value HPXML for the residential energy efficiency industry. For more information about HPXML, or to subscribe to the blog, visit www.hpxmlonline.com.





Julie Caracino is the Director of Policy and Programs at Building Performance Association. As chairperson of the HPXML Working Group, she facilitates the development of HPXML and works with industry stakeholders to increase its adoption and use among software developers processing home energy data.