DEER 2020

Commission staff, with the assistance of its DEER contractor team, developed a set of revisions for DEER2019 and a DEER2020 update in compliance with D.15-10-028, D.16-08-019, and Resolution E-4818. The updates were adopted on October 11, 2018 by the Commission via Final Resolution E-4952, issued on Energy Division’s own motion pursuant to Decision D.15-10-028. A summary of each of the changes can be found in the Attachment of Resolution E-4952. Errors and clarifications for the Resolution discovered after its passage are documented in the DEER2020 Update errata document. This web page provides general information about the updates and links to more detailed documentation and supporting materials. 

The proposed update was first described in a Scoping Memo issued by Commission staff May 9, 2018. Parties submitted comments on the proposed updates per the Draft Resolution E-4952 Comment Letter. The scoping memo solicited comments from parties which were filed later in May 2018. The commission staff and its DEER contractor then provided responses to the comments in the Draft Resolution Attachment, as well as incorporated appropriate changes to the update scope as reflected in the Draft Resolution and its Attachment.

Some minor typos, broken links and missing file references for the Draft Resolution E-4952 were identified and corrected in an Update to the Attachment. A public webinar for Draft Resolution E-4952 covering the DEER2020 updates and DEER2019 revisions was held September 10, 2018. Webinar slides are available here: PowerPoint Version PDF version


The DEER2019-2020 update included these categories of proposed changes:

  • Peak Period Definition: Peak period demand values have been updated for all measures based on the new peak period definition proposed by the working group established in response to Resolution E-4867.
  • Addition: New measures are added in response to Program Administrator requests or due to the proposal to move non-DEER workpaper measures into DEER.
  • Correction/Methodology Update: Previous measure values are changed due to errors or improvements identified in the existing DEER measure assumptions, methods or values. NOTE: An Extended-Hours Prototype was considered in the Scoping Memo, but not pursued for the final update. This new commercial building prototype would have included extended hours of operation and high load activity areas such as clean rooms, manufacturing process, or data centers, and used central chillers as the main cooling source.
  • Code Update: Measure code baselines are updated in response to adopted state or federal code changes becoming effective.
  • Evaluation Update: Measure assumptions or analysis methods are updated as a result of recent evaluation data.

LED Indoor and Outdoor Lighting

The DEER2019 update incorporates the standard practice baselines from recent dispositions covering exterior, interior low-bay, interior high-bay, screw-in and can-retrofit lighting. Measures that were previously identified in the Preliminary Ex Ante Review database (PEARdb) have been migrated to the Ex Ante database (EAdb) and identified as DEER2019 measures. In addition to incorporating measures covered by recent workpaper dispositions, DEER2019 updates the standard practice baseline for all other normal replacement (NR), new construction (NC), replace-on-burnout (ROB), and accelerated replacement (AR) measures to be based on LED technologies. This includes LED ceiling, troffer and retrofit kits measures that have previously been defined with T8 linear fluorescent baselines. Supporting documents for revised lighting measures are as follows:

DHW Rating Change

In June of 2017, federal requirements for rating of small and residential use water heaters changed from Energy Factor (EF) to Uniform Energy Factor (UEF). At the time of issuance of the DEER update Resolution E-4867 in August 2017, available product databases published by the CEC and The Air Conditioning Heating and Refrigeration Institute (AHRI) did not include sufficient quantities of UEF rated water heaters to develop typical code baseline and measure level performance criteria. For the DEER 2019 update, these databases have been reviewed to support updates to the industry standard practice baselines and measure tiers for residential 30, 40 and 50 gallon gas storage water heaters and residential tankless water heaters. Supporting documents for the DHW measures are as follows:

  • DEER2020 CEC+AHRI_water_heater_binning_for_UEF_calcs.xlsx: Analysis of CEC and AHRI databases to determine Code/standard practice and Measure technology performance characteristics
  • DEER-WaterHeater-Calculator-v3.2.xlsm: (updated 25 Sept 2018) Water heater impacts calculation workbook for use in 2019 (which corrects an error in the previously released version). This workbook has been updated to reflect revised measure technology definitions  which use UEF replacing EF for the rating
  • DEER-WaterHeater-Calculator-v3.3.xlsm: Water heater impacts calculation workbook for DEER2020. This workbook has been updated to use the DEER2020 vintage and and peak period definitions. The gas water heater measures are included in the PEAR database as part of the DEER2020 update.

Accelerated Replacement NTG Values for DEER2019

Decision 16-08-019 and Resolution E-4818 established an expanded framework for applying the accelerated replacement dual baseline approach where savings are estimated above the existing baseline for the RUL and above the standard practice or code baseline for the post-RUL period (equal to the EUL minus the RUL of the replaced equipment).  Similarly, the use of normalized metered energy consumption (NMEC) for estimating savings is based on the existing equipment baseline. Historically, evaluation results at either the measure level or program activity level have been presented as a single net-to-gross value that was not differentiated based on the measure application type (such as accelerated replacement or normal replacement) or baseline (i.e. existing conditions, standard practice or code). DEER adopts an approach for developing an appropriate NTG values for AR and NMEC measures and projects based on existing DEER NTG values modified by a methodology adopted by D.17-09-025 as used in the develop of energy savings goals.

Support Tables

Measure Application Types Abbreviation
New Construction NC
Normal Replacement (includes Replace on Burnout) NR
Accelerated Replacement AR
Add-On Equipment AOE
Building Weatherization BW
Capacity expansion (considered Normal Replacement) CE *
BRO-Behavioral BRO-Bhv
BRO-Retrocommissioning BRO-RCx
BRO-Operational BRO-Op

*Capacity expansion (CE) mistakenly appeared in Final Resolution E-4952.


Delivery Types Abbreviation
Upstream deemed upDeemed
Downstream deemed DnDeemed
Downstream custom DnCust
Downstream deemed direct install DnDeemDI
Downstream custom direct install DnCustDI
Codes and Standards (C&S advocacy and related programs) C&S









Measure Impact Type Description Abbreviation
Custom Generic: generic, site-specific calculation using approved tool or method Cust-Gen

Custom NMEC: uses a normalized, metered energy consumption (NMEC) method following CPUC-staff-issued guidance and an approved M&V/analysis plan

Custom SEM: uses a strategic energy-management method Cust-SEM
Custom RCT: uses a randomized-control trial (RCT) or experimental design method Cust-RCT
Deemed DEER: uses DEER-adopted values Deem-DEER
Deemed Workpaper: uses values from an approved workpaper Deem-WP










Peak Period Update

Resolution E-4867, issued August 24, 2017, which approved the DEER2019 update and revisions to DEER2017 and DEER2018, ordered the utilities to establish a working group to propose adjustments to the definition of the Peak Period. This working group convened two meetings, which occurred April 3 and 16, 2018, and produced a report on May 4, 2018. The recommendation in the working group report were considered along with comments on the report and additional considerations as noted in the Resolution E-4952. The Peak Period definition change is proposed for adoption as noted below.

Peak demand savings for DEER measures were re-evaluated based the order by the CPUC to update the peak period definition as quoted below.

Resolution E-4952 Ordering Paragraph 1: Effective January 1, 2020 the DEER demand reduction shall be defined as the average demand impact as would be “seen” at the electric grid level for a measure averaged across 15 hours from 4 p.m. to 9 p.m. during the three consecutive weekday period containing the highest algebraic sum of: the average temperature over the three-day period, the average temperature from noon to 6 p.m. over the three day period, and the peak temperature within the three-day period. The three Peak Period days shall not include a holiday, and shall fall within the dates of June 1 through September 30, inclusive.  Holidays within the possible peak dates include the nearest weekday to the Fourth of July, and Labor Day. A Peak Period shall be selected for each of the 16 California climate zones, based on the most current weather data sets and day-of-week sequencing adopted for the California Title 24 Building Energy Efficiency Standards, as published by the California Energy Commission.

The new peak period definition utilizes the same three-day heat wave as defined for each climate zone in the previous versions of DEER.  A workbook developed for DEER2014 (see CZ2010 Peak Period Determination - v3.xlsm) contains the data and calculations used to select the peak days for each of the 16 California climate zones adopted by the California Energy Commission for use in Title 24 Building Energy Efficiency Standards analysis. As noted above, the new peak period is from 4 p.m. to 9 p.m. instead of the previous 2 p.m. to 5 p.m. interval. All previous DEER measures with no expiration date, or with an expiration date after December 31, 2019 have updated peak demand savings based on the new peak period definition.

Lighting HVAC interactive effects (IE) values are updated based on the new peak period definition and other updates and fixes applied to the simulation prototypes as noted below. The IE tables have been updated for 2020 and are available in the Support Tables section of READI in the Energy Impacts group, and have been compiled into a single Lighting HVAC IE workbook. Updated weights tables and the Residential and Commercial HVAC IE development workbooks are also available.

Efficient Furnace Fan Motor

The commercial and residential furnace measures were updated and augmented to include the option of higher efficiency supply-air fan motors. The previous furnace efficiency measures include only impacts to the gas consumption of the higher-efficiency furnace. The ECM furnace fan motor was estimated to save 18% on average compared to the baseline Permanent Split Capacitor (PSC) motor. The derivation of this estimate is provided in DEER2020_FurnaceFan.xlsx.

Expanded HVAC Savings Methods

To support development of alternative measure definitions for chillers, and to extend the DEER chiller savings calculation methods to custom projects, DEER now includes a chiller savings calculation workbook, DEER2020_Chiller_Workbook-v1.xlsx, which utilizes the DEER chiller simulation results to develop savings of chiller measures that incorporate designated non-DEER measure characteristics. Detailed guidelines for project inputs, chiller inputs and calculation results are provided the document DEER2020_Chiller_Workbook Guide.

A set of chiller efficiency measures has been added for the scenario in which a single chiller in a multi-chiller cooling plant is replaced with a higher efficiency unit, and that unit is operated as the lead chiller throughout the year. The “lead chiller” has much higher operating hours and therefore these measures will have higher savings per ton. Lead chiller measures may only be utilized in custom programs and shall not be used in deemed downstream rebate, upstream incentive or direct install programs. Custom programs for lead chiller measures shall include pre- and post-installation measurement and verifications that support the measure chiller is installed and operating as the lead chiller.

The workbook DEER2020-DEER2017_ChillerImpacts_Comparison.xlsx provides a comparison of DEER2020 and DEER2017 impacts for chiller measures with the same measure performance characteristics.

Note (30 September 2018): During the development of the DEER2020 chiller results errors were noticed in the DEER2017 June 2017 update and DEER2019 chiller modeling. The peak demand period was not correctly updated for the CEC Title 24 weather file update and an error was found in the screw chiller performance curves. These errors have been corrected and updated workbooks and chiller modeling archives can be found on the DEER2017 page and the DEER2019 and June 2017 Update page.

Commercial Prototype Update

The DEER commercial energy simulation prototypes have been updated to account for all the lighting systems and activity areas defined in the DEER2016 update. Development of the updated prototypes also led to several changes to the building model assumptions. Some of these changes were needed to support the expanded activity area definitions and others were a result of the more flexible modeling framework of the new prototypes. The extensive re-development of the prototypes also led to critical review and updates of a number of model parameters, which are documented in DEER2020_Prototype_Changes.xlsx.

Building Vintage Consolidation

The DEER modeling process has used building vintages to distinguish the differing building and building system characteristics associated with the age of relevant buildings stock being served by an IOU. Each new DEER version considered changes to the definition of the new building vintage, based on code updates and improved standard practice, as well as how the lighting and HVAC system characteristics of older vintages may have changed. With many DEER updates over the past 15 years a new building vintage was defined and existing building vintage definitions were updated. This has led to defining unique characteristics for as many as 10 distinct building vintages for a single building type. For all but a few building shell measures in DEER, the vintage-specific energy impacts of a measure were rolled up into a single "existing building" vintage. The vintage-specific measure energy impacts that determined from energy simulations were rolled up based on the estimated total area of a given building type associated with each building vintage. Since the total area associated with the more recent vintages for any building type is always small compared to the total area of the older vintages for the same building type, the existing vintage was overwhelmingly representative of the older building vintage energy impacts.

For DEER2020, a new approach has been developed to eliminate the 10 individual vintage definitions as well as the "existing" vintage definition. Instead, there are three vintage classifications that represent existing buildings of different age ranges, and one new building vintage:

  • Old: Before 2002 for non-mobile homes, before 1995 for mobile homes
  • Median: 2002 to 2016 for non-mobile homes, 1995 to 2005 for mobile homes
  • Recent: 2017 to present for non-mobile homes, 2006 to present for mobile homes
  • New: new construction for any building type

The median vintage is defined with lighting and HVAC systems that cover the range of their respective EULs. As such, the median vintage is the most appropriate vintage to utilize for claims of measures that are applied to buildings whose age is unknown or undocumented. Note: for DEER2020, the code used for the median vintage is "ex" so that references to the previous existing vintage will be compatible with the updated measure energy impact results.

As a part of the vintage consolidation, several characteristics of multizone and central plant HVAC systems were updated to account for equipment upgrades that would likely have occurred in those buildings. All motor efficiencies and controls, supply air temperature controls, and duct insulation levels have been updated for the oldest two vintages to bring them up to the level of the 1996 vintage. Details are provided in DEER2020_Prototype_Changes.xlsx.

Commercial Building Outside Air

The outdoor air ventilation requirements of the commercial building prototypes are based on an adjustment to the required outdoor air flow per person along with the code-based egress requirements that specify the design area per person ; the code recommended adjustment to the egress-based occupancy rates differs from the adjustment used in the development of previous DEER versions. This correction has been applied to both occupant density and outdoor air ventilation requirements to be consistent with the code requirements. The new values used for DEER2020 and the previous DEER values are listed in DEER2020_Ventilation.xlsx. The median change in occupant density is a decrease of 25%, and the median change in ventilation requirement is a 50% increase as compared with previous DEER versions.

Other Corrections

Miscellaneous corrections are as follows:

  • Residential windows in DEER2017 were oversized by 18% due to an error in the application of window frame width.
  • The fan power relationship for two speed AC and HP measures was incorrect in DEER2017. The correction for DEER2020 results in fan power reduction in the low speed mode of approximately 15%.

Commercial HVAC Energy Code

Updates in the 2019 Title-24 requirements for commercial buildings include expanded ventilation (outdoor-air flow) rates by activity area, increased exhaust-air flow rates for some activity areas and increased values for cooling tower efficiency. These updates, which have been incorporated into the 2020 DEER building vintage and the new construction DEER building vintage prototype models, are expected to have minor effects on measure savings. Details of the updated values are listed in DEER2020_CodeUpdates.xlsx and DEER2020_Ventilation.xlsx.

Residential Shell Energy Code

Updates in the 2019 Title-24 requirements for residential buildings include changes to the roof insulation configuration in single-family buildings along with lower framed wall U-value for single-family buildings and improved window specifications for single-family and multi-family buildings. These updates have been incorporated into the 2020 DEER building vintage prototype models. Overall, wall insulation increases about 7%, and window performance increases about 5%. Attic radiant barrier requirements have been removed from several climate zones, and roof insulation requirements are slightly more stringent, and will result in reduced savings from duct loss measures. Details of the updated values are listed in DEER2020_CodeUpdates.xlsx.


Updates to HVAC measures reflect recent ex post evaluations: Residential HVAC maintenance and non-residential HVAC maintenance and upstream packaged measure NTG values are updated, effective January 1, 2020, based on recent evaluation results.

Direct Install to Hard-To-Reach NTG retained: Since the 2008 version, DEER has included a higher NTG value of 0.85 for direct install deemed measures into hard-to-reach markets. Commission staff reviewed the evidence gained through almost ten years of evaluation results. In review of the most recent evaluation results along with overall 2017 deemed claims, Commission staff does not find there to be a preponderance of evidence to support reducing the NTG value for direct install programs into HTR markets to equal that for the general market. A review of 2017 claims (see 2017-HTRNTG-DeemedClaims-21Aug2018.xlsx) shows that over 50% of HTR NTG claims are for lighting lamp or fixture measures with higher measure level NTG values than the existing HTR value.

Other NTG updates

Commission staff have completed a comprehensive review of the DEER NTG values along with NTG values that have been assigned to deemed measures through recent workpaper dispositions. Many NTG values are now revised, removed or combined with other NTG values to reflect most recent workpaper dispositions, evaluation results or code changes.

Out-of-date measure criteria:  Some measures have incorrect measure specifications and in some cases there are no current evaluation results to support an NTG value that is different from the DEER default. Such values have been updated, removed or replaced.

Values that are not significantly different from the DEER defaults: In some cases, measure specific NTG values do not differ by a large amount from the DEER defaults. Such values have been removed.

Lighting NTG values to reflect recent dispositions: The 2018 Phase 1 lighting dispositions updated NTG values for all LED measures. The DEER2019 expands on these dispositions to revise the code/standard practice baseline for all hardwired LED fixtures to be a typical performing LED fixture.

Table simplification: Commission staff have revised the NTG table to remove most descriptive fields and substituted direction in the comments section that describes under what circumstances an NTG value shall be used. Criteria include measure type (deemed, custom, etc.), application type (NC, NR, AR, etc.) or delivery type (downstream, upstream, downstream DI, etc) and any measure technology requirements.

The updated NTG table is downloadable using the READI tool and also here (updated 18 Sept 2018).

Effective Useful Life

D.16-08-019 created he Behavioral, Operational and Retrocommissioning (BRO) measure classification with EUL values of one to three years with retrocommissioning assigned a three-year EUL. Resolution E-4818 directed that all measure which utilize a degraded performance baseline and/or are restorative of performance in nature be classified as retrocommissioning. The DEER EUL/RUL table has been updated to follow these policy directions. This policy direction was effective 1 January 2017.

Resolution E-4818 re-affirmed the long-standing policy that EUL values for add-on equipment measures (including wall, floor and ceiling insulation added to existing insulation) are limited to the RUL values of the host equipment. The only exception to this is when the add-on measure is part of a new installation in which case the EUL of the add-on equipment is limited by the EUL of the host equipment. This DEER update add specific language and provides examples to guide future application of this policy to measure EUL/RUL assignments.

LED screw-in lamps have a spread of manufacturers rated life values ranging from 25,000 to 50,000 hours with an Energy Star minimum requirement of 25,000 hours. These ratings are based upon a specific test method that may not provide results that are a good indicator of expected life in real installations. The results of CPUC laboratory test show that LED A-lamps are unlikely to obtain their rated life or even the Commission staff approved value of 20,000 hours. Based on the testing result the LED screw-in A-Lamp life is reduced from 20,000 hours to 10,000 hours. This change is effective 1 January 2019.

The updated EUL table is downloadable using the READI tool.

Custom Project/Measure GRR

Although an update to the default gross realization rate for custom measures and projects is within the scope of this Resolution, Staff determined that the values established by Decision 11-07-030 may not be modified through this Resolution, thus remain 0.90 at this time. The results of recent CPUC sponsored laboratory testing show that LED A-lamps are unlikely to obtain their rated life or even the Commission staff approved value of 20,000 hours. Based on the testing results the  LED screw-in A-Lamp EUL is reduced from 20,000 hours to 10,000 hours effective 1 January 2019. 

Additional Resources

All energy simulations to support DEER2020 were conducted using an updated version of the measure analysis software (MASControl3) (Updated 30 Sept 2018). For more information about MASControl3, see MASControl3 Resources.

Download Title Notes Start Date End Date Date Posted Actions
Errata for Resolution E-4952 DEER2020 Update v3 2020 Jan 1 2023 Feb 2 See history
Resolution E-4952 DEER2020 Update

Approved on 2018-10-11.

2020 Jan 1 2018 Oct 11 See history
Commercial Prototype model parameter updates The DEER commercial energy simulation prototypes have been updated to account for all the lighting systems and activity areas defined in the DEER2016 update. Development of the updated prototypes also led to several changes to the building model assumptions. Some of these changes were needed to support the expanded activity area definitions and others were a result of the more flexible modeling framework of the new prototypes. The extensive re-development of the prototypes also led to critical review and updates of a number of model parameters, which are documented in DEER2020_Prototype_Changes.xlsx. 2022 Jan 25 See history
Building Vintage Consolidation details As a part of the vintage consolidation, several characteristics of multizone and central plant HVAC systems were updated to account for equipment upgrades that would likely have occurred in those buildings. All motor efficiencies and controls, supply air temperature controls, and duct insulation levels have been updated for the oldest two vintages to bring them up to the level of the 1996 vintage. Details are provided in DEER2020_Prototype_Changes.xlsx. 2022 Jan 25 See history
Commercial HVAC Energy Code DEER2020_CodeUpdates Details of updated values 2022 Jan 25 See history
DEER2020_Ventilation Details of updated value list 2022 Jan 25 See history
DEER2020_CodeUpdates Details of updated values 2022 Jan 25 See history
2017-HTRNTG-DeemedClaims-21Aug2018 A review of 2017 claims 2022 Jan 25 See history
SupportTable-NTG2020-rev18Sep2018 The updated NTG table. Last updated September 18, 2018 2022 Jan 25 See history