Office of Energy and Sustainable Development
Office of Energy and Sustainable Development

Building Energy Saving Ordinance (BESO)

BESO to replace RECO/CECO 
Effective December 1, 2015, Berkeley's Energy Saving Ordinance (Berkeley Municipal Code 19.81) will replace both the Residential and Commercial Energy Conservation Ordinances (RECO and CECO). With BESO, the RECO/CECO requirements of installing energy and water efficiency improvement measures, will no longer be required. Instead, BESO requires all buildings to complete building-specific energy assessments, as well as publicly report a building's energy and water efficiency. BESO compliance is required prior to selling a building or due based on a phase-in schedule. When selling a building, compliance can be deferred to the buyer for up to 12 months. Highly efficient buildings that have completed a qualified energy upgrade are exempt from the assessment requirement.

Transition Period: The transition from RECO/CECO to BESO will occur between October 9, 2015 and December 1, 2015.  As of October 9, 2015, RECO and CECO requirements will no longer be required at time of building renovation due to enhanced energy codes and CalGreen standards. For buildings up for sale between October 9 to December 1, 2015, sellers may choose to either complete RECO/CECO measures or a BESO assessment. As of December 1, 2015, all new sales transactions of medium and small buildings, including homes, must comply with BESO. Previous completion of requirements under RECO/CECO will not fulfill BESO requirements. For more information on the transition schedule, see: Transitioning from RECO/CECO to BESO.

What is BESO: BESO stipulates that owners of all buildings in Berkeley must conduct an energy assessment and report on building efficiency or document high performance building status. The timing, frequency, triggers, and specific type of energy assessment is dependent on the size of the building. The goal of BESO is to accelerate greenhouse gas emissions reductions to help us meet our Climate Action goals, save money on utility bills, and improve occupant health and comfort. See the BESO flyer for an overview.

BESO Energy Assessment Requirements: BESO affects all buildings in Berkeley. BESO requires building energy assessments at time of sale as well phased-in by building size and year. BESO energy assessments are conducted by a Registered Energy Assessor who will evaluate a building’s specific energy and water saving opportunities. Reports based on these assessments inform the building owner, as well as potential buyers and renters, of building energy performance and cost-effective opportunities for improvement. It is the building owner’s decision whether to take action on the energy and water saving opportunities and health improvements listed in the energy assessment.

BESO Reporting Schedule: BESO requires energy assessments at time of sale for medium, small, and single family buildings, as well phased-in by building size and year for all buildings, with the exception of homes (1 to 4 units).

  • Time of  Sale Schedule (excludes large buildings)  
    • October 9 to December 1, 2015 Buildings being sold may comply with either  RECO/CECO or BESO
    • December 1, 2015 Buildings being sold must comply with BESO
  •  Phase In Schedule (excludes homes of 1-4 units), see table below.

Building Size (sq ft)

Due  Date

Reporting Cycle

Large buildings: 50,000 or more


Energy Assessment every 5 years
ENERGY STAR Performance Report annually

Large buildings: 25,000- 49,999


Medium buildings:15,000-24,999


Energy Assessment every 8 years 

Medium buildings: 5,000-14,999


Small buildings: Less than 5,000 (excluding 1-4 unit homes)


Energy Assessment every 10 years


To become a BESO Registered Energy Assessor see:

For questions, email or call 510-981-7432.

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