The energy efficiency actions of California homeowners who installed rooftop solar electric systems are providing insights into the connection between solar adoption and energy upgrades that could help in the design of future residential energy programs.

A study of San Diego-area residents who participated in the California Solar Initiative rebate program shows future solar adopters may be an ideal market segment for making more comprehensive energy upgrades, according to the Center for Sustainable Energy (CSE).

Understanding the relationship between solar adoption and energy efficiency measures is critical given the state government's efforts to expand the residential energy efficiency market and its aggressive plans calling for reducing energy consumption in existing residential buildings 40% by 2020.

CSE researchers surveyed 2,350 solar homeowners in the San Diego Gas and Electric service territory to understand the various factors motivating their investment in a solar photovoltaic (PV) system and to assess their perspectives on energy efficiency.

While the majority of respondents indicated saving money on electricity costs as the most important reason for going solar (74%) and for making any energy efficiency upgrades (71%), nuances in motivations across demographic groups reveal some distinct differences that shed light on differing energy views.

The survey found that 87% of survey participants had engaged in energy efficiency, the majority only taking basic actions prior to solar installation, such as installing low-energy lighting and appliances.

Following the market segmentation descriptions developed by Opinion Dynamics Corp. for the California Public Utilities Commission, a portion of the survey group was divided into "leading achievers" and "practical spenders," based largely on household income, education and other demographics.

According to Ria Langheim, a CSE research analyst, the results confirmed that leading achievers were more motivated to install solar because of environmental concerns and the desire to reduce reliance on fossil-fueled energy, while practical spenders perceived solar as more of a significant investment that increased their property value.

Langheim said practical spenders link energy efficiency to home maintenance as an ongoing process but with the added benefits of comfortable indoor temperatures and improved air quality. Among the leading achievers, there was more motivation for energy efficiency around being green in general and reducing their carbon footprint. They also were more likely to see energy efficiency upgrades as a prerequisite to solar to reduce consumption and minimize PV system size.

The data indicate that solar customers appear to understand that deeper energy efficiency upgrades offer not only cost savings but also other factors related to home comfort, health and safety that provide the opportunity to engage them in taking additional energy measures. According to Langheim, the implications of this are potentially large considering the savings missed when energy efficiency is not addressed comprehensively before installing solar.

"Consideration should be given to integrating solar into energy efficiency programs and framing solar as a component of a comprehensive home energy upgrade," Langheim said.

"This may help future solar customers to explore the full range of energy efficiency options as well as encourage contractors to offer both energy efficiency and solar installation services."

Langheim will present study results at the American Council for an Energy-Efficient Economy (ACEEE) conference, "The Next Generation: Reaching for High Energy Savings," to be held Aug. 17-22 at the Asilomar Conference Center, Pacific Grove, Calif.

The entire report, Energy Efficiency Motivations and Actions of California Solar Homeowners, is available online at CSE's website here