Incorporating real-world data into measure lifetime estimates: How long does energy efficient equipment really last on-site?

Panel: Panel 4: Monitoring and evaluation

Authors:
Rose Woods, Skumatz Economic Research Associates, Inc. (SERA), USA
Lisa A. Skumatz, Skumatz Economic Research Associates, Inc. (SERA), USA

Abstract

In work for a large west coast agency, the authors conducted a detailed assessment of more than 100 measure retention / lifetime studies to identify the real-world lifetimes for numerous energy saving measures used in: 1) Residential, 2) Low income, 3) Commercial / industrial, 4) agricultural, and 5) military buildings. Estimated useful lifetimes (measure lifetimes), in conjunction with energy savings estimates, are the key elements in computing energy savings for a program or intervention. Many of these EULs had not been updated for more than a decade.

The study provides quantitative information on: 1) updated measure lifetimes for scores of commonly-installed program measures; 2) information on measures for which reliable lifetime information is not currently available; 3) information on technical degradation studies, and 4) best practices for measure lifetime analyses.

For each study, the authors conducted an exhaustive review of program measures, sampling methodologies and approach; field work; data validation; and analysis steps to determine whether reliable lifetime information could be gleaned from the study. The paper summarizes these results and provides information on updated / recommended EUL estimates for energy efficiency equipment. The implications related to gaps in available EUL information – especially as it relates to key equipment – and reliable estimates of EUL values for planning for future programs are presented.