February 2008

Volume 17, Number 2

Get the PDF

By downloading this digital content, you agree to BuildingGreen’s terms and conditions of use.

California to Require Net-Zero-Energy Buildings

Printer-friendly versionSend to friend


One of four demonstration net-zero-energy homes built by Clarum Homes in Borrego Springs, California, this home uses a 3.75-kilowatt photovoltaic system. Each home takes a different approach to energy efficiency, with different wall assemblies and cooling systems.

Photo: Clarum Homes and Ruby Moon Photography

Every two years, the California Energy Commission (CEC) releases an Integrated Energy Policy Report in which it makes recommendations for energy policy in the state, including changes to Title 24, the energy efficiency portion of the building codes. In its 2007 report, CEC recommends adjusting Title 24 to require net-zero-energy performance in residential buildings by 2020 and in commercial buildings by 2030. According to Panama Bartholomy of CEC, the commission does not need new legislation to incorporate these goals and is already moving to put them in place. “The 2008 standards will get us closer to these recommendations,” he said, referring to the Title 24 update currently moving through the state’s rulemaking process.

The goals set in California were inspired by the 2030 Challenge goals, in which the nonprofit organization Architecture 2030 calls for no fossil fuel use for buildings by 2030. But California's goals are focused on net-zero-energy performance instead of fossil fuel use. CEC based its definition of net-zero-energy performance, and many of its recommendations, on a report by the California Public Utility Commission (CPUC), which states that a goal of “no net purchases from the electricity or gas grid” may be met with energy-efficient design and “onsite clean distributed generation.” Neither agency explains how net-zero-energy performance would be calculated in a building needing to offset natural gas usage with renewable energy. This offset could be calculated in several ways (see EBN Vol. 14, No. 10).

While the California goals are not expressed in terms of carbon, both the CEC and CPUC reports emphasize carbon emissions reduction as their overarching goal. A 2006 law requires California to reduce greenhouse gas emissions to 1990 levels by 2020; this law has spurred several initiatives to promote renewable energy projects, including small-scale renewable generation projects for residential and commercial buildings.

The initiative to require net-zero-energy buildings applies only to new construction. To achieve energy savings in existing buildings, CEC is pursuing legislation to require “retrofit at resale”—improvements in energy performance prior to an existing building’s sale. Ordinances of this type already exist in San Francisco and Berkeley. According to Bartholomy, several state legislators are looking at how such legislation would work and how the costs of required retrofits would be covered.

– Allyson Wendt

For more information:

California Energy Commission 2007 Integrated Energy Policy Report


California Public Utilities Commission Decision on Energy Policy


Comments (0)

Post new comment

Welcome !
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.
  • Glossary terms will be automatically marked with links to their descriptions. If there are certain phrases or sections of text that should be excluded from glossary marking and linking, use the special markup, [no-glossary] ... [/no-glossary]. Additionally, these HTML elements will not be scanned: a, abbr, acronym, code, pre.

More information about formatting options

February 3, 2008