California Home Energy Use Survey

California seeks to meet aggressive goals in the residential sector, including a zero net energy performance standard for all new homes and implementation of all cost-effective efficiency measures in existing homes by 2020. Pacific Gas and Electric Company's Codes and Standards (C&S) Program is one key component to help meet the state’s goals. PG&E contracted with Evergreen Economics to conduct new primary research to provide current and robust data on equipment saturations, efficiency levels, vintages, and operating hours to support the development of program strategies to make progress towards the state’s goals.

We launched the PG&E Home Energy Use Study in late 2015 by recruiting a representative sample of 1,000 homes for on-site surveys, which were conducted during the first half of 2016. Evergreen developed the on-site survey sample frame using PG&E’s customer information system data, with stratification based on home type, income, and region (groups of counties). We collected comprehensive equipment holdings and characteristics, including a customer interview.

The study also includes a second phase with full-scale end use metering at a sample of surveyed homes. In mid-2016, we selected a nested sample of surveyed homes to recruit for full-scale metering to measure energy usage at the end use level. Evergreen and our study partner, kW Engineering, developed a custom suite of monitoring equipment, communication devices and sensors to measure equipment usage and load profiles, as well as conditioned and ambient air temperatures. The team will collect five-minute interval data for all major end uses and a sample of plug loads and electronics. The plan is to keep the meters in place for several years in order to capture usage trends over time. We also plan to conduct periodic (e.g., quarterly) web surveys with phase two participants to gather longitudinal information on energy equipment upgrades and replacements.

This study is an important resource to further the state’s progress in meeting its ambitious energy goals. These data may be used in conjunction with prior studies to show time-series changes in saturations of key energy efficiency equipment types; update residential equipment load shapes; and identify remaining savings potential for appliances, home electronics and miscellaneous plug loads. The longitudinal nature of the study also provides the ability to track changes over time in equipment holdings and usage patterns, with opportunities via the web survey to complement the measured data with customer preferences and motivations.