PNNL

Improving the effectiveness of building codes to deliver home energy savings requires an understanding of how codes are being implemented in new homes. Researchers at PNNL have come up with a creative framework that successfully obtained this information for large groups of homes in eight states—without the need for extensive and costly field surveys.

The technique’s resulting information is crucial for policy-makers and other stakeholders who want insights into code compliance and potential energy savings. Such data can help justify future investments in energy code training and related energy efficiency programs.  

The PNNL methodology—and how it was used to study code implementation and energy-savings potential in the eight states—is outlined in the paper, “Assessing Overall Building Energy Performance of a Large Population of Residential Single-family Homes Using Limited Field Data.” The paper is featured in the Journal of Building Performance Simulation.  

A Matter of Compliance

Residential structures are responsible for about 20 percent of total U.S. energy consumption. Building codes exist to provide requirements for increasing energy efficiency, but their effect is limited without proper compliance monitoring and approaches to make improvements. While the ideal method to evaluate code compliance and performance in the eight states would have been site visits to every new home in each state, obviously that approach is neither cost-effective nor practical.

That’s where PNNL’s newly developed framework comes in. Participating field teams gathered limited data, including key construction details, from a given number of homes in each state and paired the information with a sampling technique and energy simulations that employed models derived from a PNNL-developed prototype home.

This procedure successfully analyzed the code compliance and energy use of residential structures in the eight states—Alabama, Arkansas, Georgia, Kentucky, Maryland, North Carolina, Pennsylvania, and Texas. The method also revealed each state could potentially achieve significant savings by bringing buildings up to code.

“Those savings are appealing, but what’s even more interesting about this study is the limited number of home visits—combined with large-scale building simulation—which make possible the evaluation of compliance in terms of energy consumption on the scale of U.S. states,” says PNNL’s Rosemarie Bartlett, project manager.

While researchers used the EnergyPlus simulation tool to run tests and analyze data for this particular experiment, the new framework is generic and can be applied to any number of different energy simulation programs.

The procedure for the study featured three phases. The first phase involved gathering and comparing field and simulation data, while the second phase informed and advised stakeholders on how best to bring buildings up to code. Those two phases have been completed in most states. The nearly-complete third and final phase involves collection of further field data to analyze the effectiveness of the second phase.

Although limited by random, small field data sets, this method shows promise in providing officials with information that can guide the education, training, and outreach necessary to bring more buildings up to code and increase energy efficiency.