Residential Energy Use

How Are We Doing?

Electricity use received a thumbs up because average annual residential electricity use per household in San Diego County decreased by about 5% from 2018 to 2019. Local consumption was comparable to other major urban coastal counties in California and has remained on a slightly downward trend over the last decade. Building energy use includes both electricity and natural gas use. Certain households in San Diego County also use other fuels, such as propane, for space heating and water heating at home. Reducing fossil fuel based energy use and increasing renewable energy lead to greenhouse gas emissions reduction. To learn more about how the San Diego region is leading the State in renewable energy generation, see Renewable Energy & Storage indicator. Want to know more about what we're measuring?

thumbs up

Residential energy use remained low among California counties

The San Diego County average annual electricity use per household decreased 5% from 2018 to 2019, from 6,041 kWh to 5,817 kWh. Other comparison counties all showed an increase in electricity use from 2018 to 2019, ranging from a 2% to 5% increase. The household electricity use in San Diego County is similar to that in Santa Clara County and San Luis Obispo County. Fresno homes have the highest electricity use on average, around 9,000 kWh in 2019, while San Francisco homes have the lowest electricity use on average, around 4,000 kWh in 2019.

Natural gas use per household has been decreasing over the past ten years, especially since 2013. However, the San Diego County average annual natural gas use per household increased 14% from 2018 to 2019, from 232 therms to 265 therms per home. Other counties shown in the chart also had an increase in natural gas use from 2018 to 2019, ranging from 1% to 5%. San Diego homes have by far the lowest natural gas use among the counties shown in the chart above, most likely due to milder climate and less space heating needs. The household natural gas use in San Francisco and Santa Clara Counties are very similar; and the household natural gas use in Fresno and San Luiso Obispo Counties are also similar.

It is the combined energy use in homes, the sum of electricity and natural gas use converted to a common energy unit, that really indicates the change in household energy use over time.  Once converted to the common unit MMBtu, the total residential energy use (electricity + natural gas) can be compared across counties. Homes in Fresno County had the highest residential energy use in 2019 with 53% coming from natural gas. Although San Francisco homes may have the lowest electricity use, electricity use only accounts for 28% of the residential energy use with the remaining household energy coming from natural gas. San Diego County has the lowest residential use among the counties in the chart, most likely due to our milder year-round climate.

San Diego County residential electricity usage spikes during late summer with a smaller peak in December and January. In summer months, electricity used for air conditioning increases. Electricity used for cooling is impacted by minimum and maximum temperatures, as well as how hot the temperature is on a given day or a period of days. Cooling degree day (CDD) is an indicator measuring how hot the temperature is on a given day or over a period compared with a base temperature of 65 F, the temperature which we don’t need heating or cooling to be comfortable. Based on the National Weather Service data, the number of CDDs in San Diego County from July through September 2020 was 722, compared with 615 CDDs during the same three month period in 2019.

Why is Building Energy Use Important?

High quality of life means the region boasts a thriving economy and a healthy environment accessible to all in the community.

  • Environment: Reducing the use of fossil-fuel based electricity and natural gas reduces their polluting impacts on public health outside and inside our buildings and homes today and will help reduce the effect of climate change for future generations. 
  • Economy: Although California has some of the highest electricity rates in the country, Californians spend 2% of their pre-tax income on electricity bills and California ranks the sixth lowest in electricity burden for all states. Similarly, while the San Diego utility SDG&E has among the highest electricity rates in the country, because electricity use is relatively low compared with other regions in the state, electricity bills are lower than in other service territories.
  • Equity: Any increases in building energy bills will have disproportionate effects on communities with high concentrations of poverty, where people are more likely unable to afford the increasing electricity bills or lack access to air conditioning. As extreme heat events increase in frequency and intensity in the entire region, requiring greater use of air conditioning, conserving home energy through more efficient buildings, better designed greener communities, and access to cooling centers will help keep bills low and improve the quality of life especially for these communities.

Regional Response


The City of Encinitas is in the process of adopting a local ordinance requiring all (residential and non-residential) newly constructed buildings in the City to use electricity for all appliances. By avoiding natural gas appliances and instituting renewable electricity policies in Encinitas’ Climate Action Plan, greenhouse gas emissions will be reduced and indoor air quality will improve.


The University of California, San Diego (UCSD) has a goal of reducing energy use by 2% per year at each campus. At UCSD, one of the projects contributing to this goal is a computerized Energy Management System connecting all major campus buildings and centrally monitoring and controlling energy use systems based on occupancy. This helps reduce energy use during evenings, weekends and holidays. Similar energy management system projects are underway in the County of San Diego.


Several Local Government Partnerships (LGPs) were developed between SDG&E and SANDAG, the Port of San Diego, and several large jurisdictions to identify opportunities to implement energy savings at government facilities and within their communities. The development, monitoring and implementation of energy reduction measures through Climate Action Plans has been one tangible outcome of these partnerships.

University of San Diego Efforts & Projects

In 2020, the University of San Diego (USD) partnered with an engineering team led by Willdan, Inc. to create an Energy Master Plan (EMP) to achieve carbon neutrality for campus energy use. From February 2020 through April 2021, USD and Willdan worked to produce a comprehensive document to reduce campus energy consumption through efficiency and conservation measures, add on-site renewable generation and energy storage, and replace natural gas fueled equipment with electric versions, thereby eliminating almost all carbon emissions from campus energy use. The EMP also calls for residual emissions to be offset, unless cost-effective measures to eliminate these projected remaining emissions are developed. Not only do these strategies guide USD to achieve carbon neutrality from its energy use, over the 14 year timeframe for implementation, the EMP is projected to save the university almost $8 million. Resilience measures, primarily in the form of cleaner, reliable back-up power options are also included, as is an expansion of electric vehicle infrastructure. 

Finally, as part of developing the EMP, the USD team emphasized the importance of including students in both the production and implementation of various aspects of the strategy. USD and the Willdan team created internships for two engineering students to assist in research and data analysis for the EMP. Further, the final EMP has an entire section devoted to potential projects that USD students could implement to help establish the EMP, starting in 2021. 

For more information, see USD Office of Sustainability.


What Are We Measuring?

We measure residential energy use by tracking average annual electricity use and natural gas use per household in San Diego County. We compare that regional consumption to other California counties on an annual and monthly basis.