September 9, 2024
EXECUTIVE SUMMARY
The purpose of this document is to summarize how the Energy Performance approach reach code ordinance provides Hourly Source Energy compliance margins that are achievable for new construction buildings in Cupertino (Climate Zone 4) while meeting two criteria:
1) Cost-effective, for approval by the California Energy Commission (CEC). 2) Technically feasible, using appliances with efficiencies set at the minimum federal requirements.
The Energy Performance approach encourages new construction buildings to reduce their emissions, and improve outdoor and indoor air quality. This is achieved by requiring new construction buildings utilizing the performance pathway to meet an Hourly Source Energy compliance margin which is stricter than that set by the state in the 2022 Energy Code, Title 24, Part 6. The reach codes mitigates legal risk with the Energy Policy and Conservation Act (EPCA) as a result of the California Restaurant Association vs. City of Berkeley ruling by remaining fuel neutral through providing cost-effective pathways to compliance for both mixed-fuel and all-electric buildings utilizing appliances with efficiencies set at the minimum federal requirements.
Table 1. Summary of EDR1/Source Energy Compliance Margins and Cost-Effectiveness Data for Climate Zone 4 Building Type Metric
Reach Code
Compliance
Margin
Package Package Details
Achieves
Compliance
Margin?
Is it Cost-
Effective? Links
Single Family EDR1 9 or
greater
All-electric Both major appliances are heat pumps (water heating and space heating & cooling). Yes Yes Report
SFNC Study
Data Mixed-fuel Combustion equipment is used with building efficiency measures, additional PV, and a battery. Yes Yes Multifamily (3-
stories and
less)
Source
Energy
9% or
greater
All-electric Both major appliances are heat pumps (water heating and space heating & cooling). Yes Yes
Report
MFNC
Study Data
Mixed-fuel Combustion equipment is used with building
efficiency measures, additional PV, and a battery. Yes Yes Multifamily (4-
stories and
more)
Source
Energy
1% or
greater
All-electric Both major appliances are heat pumps (water heating and space heating & cooling). Yes Yes
Mixed-fuel Combusting equipment is used with building
efficiency measures and additional PV. Yes Yes
Nonresidential Source
Energy
10% or
greater
All-electric Both major appliances are heat pumps (water heating and space heating & cooling). Yes* Yes* Report
NRNC
Study Data Mixed-fuel Combustion equipment is used with building efficiency measures. Yes* Yes*
*Source Energy compliance margins and cost-effectiveness results vary by prototype building, see the nonresidential report for the full set of results in more detail.
September 9, 2024
MEMORANDUM September 9, 2024 To: Christopher Jensen (Cupertino)
From: Taylor Taylor, Farhad Farahmand (TRC)
Re: Energy Performance Approach for Cupertino Reach Code
OVERVIEW
TRC provides this memo to direct readers to the references of the Hourly Source Energy margins used in the reach code ordinance. Hourly Source Energy is a compliance metric introduced in 2022 California Building Energy Efficiency Standards representing, among other things, transmission, delivery and production losses from the underlying fuel sources used to power building systems and equipment. A more thorough description of Hourly Source Energy compliance metric and relationship with other metrics is included in this Energy Code Ace document, excerpted at the end of this memo.
Cost-effectiveness studies produced by the California Investor-Owned Utilities Codes and Standards Program serve as the primary source of information. For various measure packages, these studies demonstrate Hourly Source Energy compliance margins that are achievable for new construction in Cupertino (Climate Zone 4) while meeting two criteria:
3) Cost-effective, for approval by the California Energy Commission (CEC). 4) Technically feasible, using appliances with efficiencies set at the minimum federal requirements.
Single Family
In single family only, the Hourly Source Energy metric is instead referred to as Energy Design Rating 1 (EDR1). EDR1 margins meeting the two criteria listed above are contained in the 2022 Cost-Effectiveness Study: Single Family New Construction Study (Report) and workbook (SFNC Study Data) for a 2,400 square foot single family building.
Per Figure 1 below:
The All-Electric Code Minimum package achieves an EDR1 margin equal to 8.8 (cell S230). The All-Electric Efficiency package that includes efficiency measures as well as the market baseline heat pump water heater, achieves 10.4 (cell S337).
The All-Electric Efficiency + Equipment package that includes efficiency measures as well as the market baseline heat pump water heater (which performs well above federal minimum efficiency requirements), achieves 11.9 (cell S339).
The Mixed Fuel Efficiency, PV, + Battery package achieves 13.2 (cell S347).
An EDR1 compliance margin of 9 reflects a cost-effective baseline achievable by an all-electric code minimum new construction single family building, that is also technically feasible by a mixed-fuel building with appliances efficiencies at minimum federal requirements.
MEMORANDUM (continued) August 28, 2024
To: Christopher Jensen (Cupertino)
Figure 1. Single Family (2400 square foot prototype) source energy margin results Small Homes
Information on small new construction single family homes, such as ADUs, can also be found in the single-family home sources listed above by filtering for the 625 square foot single family building. Single family homes that are less than 1,500 square feet can have difficulties meeting the margins listed above for single family homes. This is because smaller homes use less energy overall and therefore the amount of energy savings potential is diminished.
In order to prevent frequent cases of technical infeasibility, an exception is offered for homes less than 1,500 square foot, set at the target where a 625 square foot home can achieve it. Per Figure 2 below:
The All-Electric Code Minimum package achieves an EDR1 margin equal to 2.4 (cell S56). The All-Electric Efficiency package that includes efficiency measures, achieves 3.9 (cell S58). The All-Electric Efficiency + High Efficiency Equipment package that includes efficiency measures as well as the market baseline heat pump water heater (which performs well above federal minimum efficiency requirements), achieves 5.5 (cell S60).
The All-Electric Efficiency + PV package achieves 6.8 (cell S62). The Mixed Fuel Efficiency + High Efficiency Equipment package achieves 3.7 (cell S66). The Mixed Fuel Efficiency, PV, + Battery package achieves 13.3 (cell S215).
The all-electric efficiency + PV package is cost-effective and achieves an EDR1 of 6.8. Therefore, a small homes reach code compliance margin could be set as high as 6.8. The margin can be set lower, such as at a compliance margin of 4, to align with an all-electric building with a market baseline water heater, and also with the all-electric efficiency package. This encourages emissions reductions while reducing construction cost burden on smaller sized homes.
Figure 2. Single Family (625 square foot prototype) source energy margin results
MEMORANDUM (continued) August 28, 2024
To: Christopher Jensen (Cupertino)
Multifamily
Hourly Source Energy margins meeting the two criteria listed above are contained in the 2022 Cost-Effectiveness Study:
Multifamily New Construction (Report) and workbook (MFNC Study Data) for two multifamily family buildings (3- story, 39,372 ft2 and 5-story, 140,925 ft2). Per Figure 3 below:
For the 3-story prototype
The All-Electric Code Minimum package achieves an Hourly Source Energy margin equal to 9% (cell AI30).
The Mixed Fuel Efficiency, PV, + Battery package achieves 17% (cell AI36) For the 5-story prototype
The All-Electric Code Minimum package achieves an Hourly Source Energy margin of 6% (cell AI51). The Mixed Fuel Efficiency + PV package achieves 1% (cell AI156)
An Hourly Source Energy compliance margin of 9% for 3-stories and less, and 1% for 4-stories and more, reflects a cost-effective baseline achievable by an all-electric code minimum new construction multifamily building, that is also technically feasible by a mixed-fuel building with appliances efficiencies at minimum federal requirements.
Figure 3. Multifamily source energy results. Under the “prototype” column, the 3-story building is 39,372 ft2and the 5- story building is 140,925 ft2.
Nonresidential
Hourly Source Energy margins meeting the two criteria listed above are contained in the 2022 Nonresidential New Construction Reach Code Cost-effectiveness Study (Report) and workbook (NRNC Study Data) for four nonresidential prototypes (Medium Office, Retail, Quick-Service Restaurant, and Small Hotel). Per Figure 4 below:
For the Medium Office (‘MO’ tab in the workbook)
The All-Electric Code Minimum package achieves an Hourly Source Energy margin equal to 5% (cell T29).
The Mixed Fuel + Efficiency package achieves 10% (cell T6). For the Medium Retail (‘RE’ tab in the workbook)
The Mixed Fuel Code Minimum package achieves -29% (cell T6). The All-Electric + Efficiency package achieves 12% (cell T52). For the Quick Service Restaurant (‘QSR’ tab in the workbook) The All-Electric Code Minimum package achieves 42% (cell T121). The Mixed Fuel + Efficiency package achieves 12% (cell T6). For the Small Hotel (‘SH’ tab in the workbook)
MEMORANDUM (continued) August 28, 2024
To: Christopher Jensen (Cupertino)
The All-Electric Code Minimum package achieves 29% (cell T29). The Mixed Fuel + Efficiency package achieves 7% (cell T6).
For nonresidential buildings, an Hourly Source Energy compliance margin of 10% reflects the average performance of mixed-fuel buildings with appliances efficiencies at minimum federal requirements and additional non- preemptive efficiency measures. Nonresidential buildings with all-electric heat pumps at minimum federal requirements will achieve this target without any additional efficiency measures.
A subset of nonresidential buildings which utilize small rooftop HVAC, like Retail, already have heat pump as the prescriptive code minimum, which achieves the same objective as the reach code applied to the nonresidential buildings. To account for this, an exception is included for nonresidential buildings that reduces the Hourly Source Energy compliance margin to 0% (the state minimum requirement) when nonresidential occupancies are designed with single zone space-conditioning systems complying with Section 140.4(a)2.
Figure 4. Source energy margin results for Medium Office (MO), Retail (RE), Quick Service Restaurant (QSR), and Small Hotel (SH)
MEMORANDUM (continued) August 28, 2024
To: Christopher Jensen (Cupertino)
Appendix: Single Family Building Summary of Source Energy and Other Metrics
Source: Energy Code Ace – Single Family Buildings: What’s New in 2022?