California Association of Building Energy Consultants

When is PV Solar Required under the 2019 Title 24 Part 6 Energy Code?

Section 150.1 excerpts below are from the 2019 Building Energy Efficiency Standards

Section 150.1 — Performance and Prescriptive Compliance Approaches for Low-rise Residential Buildings

Section 150.1

(b) Performance Standards. A building complies with the performance standards if the energy consumption calculated for the Proposed Design Building is no greater than the energy budget calculated for the Standard Design Building using Commission-certified compliance software as specified by the Alternative Calculation Methods Approval Manual.

  1. Newly Constructed Buildings. The Energy Budget for newly constructed buildings is expressed in terms of the Energy Design Rating, which is based on TDV energy. The Energy Design Rating (EDR) has two components, the Energy Efficiency Design Rating, and the Solar Electric Generation and Demand Flexibility Design Rating. The Solar Electric Generation and Demand Flexibility Design Rating shall be subtracted from the Energy Efficiency Design Rating to determine the Total Energy Design Rating. The Proposed Building shall separately comply with the Energy Efficiency Design Rating and the Total Energy Design Rating.

EXCEPTION to Section 150.1(b)1. A community shared solar electric generation system, or other renewable electric generation system, and/or community shared battery storage system, which provides dedicated power, utility energy reduction credits, or payments for energy bill reductions, to the permitted building and is approved by the Energy Commission as specified in Title 24, Part 1, Section 10-115, may offset part or all of the solar electric generation system Energy Design Rating required to comply with the Standards, as calculated according to methods established by the Commission in the Residential ACM Reference Manual.

Note: Newly Constructed Buildings must meet the Solar Electric Generation and Demand Flexibility Design Rating stated as Energy Efficiency Design Rating (EDR).

Section 150.1(c) 14

14. Photovoltaic Requirements. All low-rise residential buildings shall have a photovoltaic (PV) system meeting the minimum qualification requirements as specified in Joint Appendix JA11, with annual electrical output equal to or greater than the dwelling's annual electrical usage as determined by Equation 150.1-C:

Equation 150.1-C Annual Photovoltaic Electrical Output

WHERE:

EXCEPTION 1 to Section 150.1(c)14: No PV is required if the effective annual solar access is restricted to less than 80 contiguous square feet by shading from existing permanent natural or manmade barriers external to the dwelling, including but not limited to trees, hills, and adjacent structures. The effective annual solar access shall be 70 percent or greater of the output of an unshaded PV array on an annual basis.

EXCEPTION 2 to Section 150.1(c)14: In climate zone 15, the PV size shall be the smaller of a size that can be accommodated by the effective annual solar access or a PV size required by the Equation 150.1-C, but no less than 1.5 Watt DC per square foot of conditioned floor area.

EXCEPTION 3 to Section 150.1(c)14: In all climate zones, for dwelling units with two habitable stories, the PV size shall be the smaller of a size that can be accommodated by the effective annual solar access or a PV size required by the Equation 150.1-C, but no less than 1.0 Watt DC per square foot of conditioned floor area.

EXCEPTION 4 to Section 150.1(c)14: In all climate zones, for low-rise residential dwellings with three habitable stories and single family dwellings with three or more habitable stories, the PV size shall be the smaller of a size that can be accommodated by the effective annual solar access or a PV size required by the Equation 150.1-C, but no less than 0.8 Watt DC per square foot of conditioned floor area.

EXCEPTION 5 to Section 150.1(c)14: For a dwelling unit plan that is approved by the planning department prior to January 1, 2020 with available solar ready zone between 80 and 200 square feet, the PV size is limited to the lesser of the size that can be accommodated by the effective annual solar access or a size that is required by the Equation 150.1-C.

EXCEPTION 6 to Section 150.1(c)14: PV sizes from Equation 150.1-C may be reduced by 25 percent if installed in conjunction with a battery storage system. The battery storage system shall meet the qualification requirements specified in Joint Appendix JA12 and have a minimum capacity of 7.5 kWh.

SNOW LOAD and PV

The California Energy Commission's BLUEPRINT Issue 133 states, "that the solar PV system requirement does not apply to buildings that cannot meet the PV system structural requirements in the CBC and CRC due to high snow loads." Please check with your local building department.

Conclusions based upon the above Title 24 Part 6 Energy Code Sections

  1. An art studio, pool house, ADU and all other types of residential buildings that are NEWLY CONSTRUCTED will require PV Solar.

    Title 24 Part 6 Energy Code Definition: NEWLY CONSTRUCTED BUILDING is a building that has never been used or occupied for any purpose.

  2. An art studio, pool house, ADU and all other types of residential buildings that are attached to an existing, conditioned, low-rise residential building are ADDITIONS and are not required to have PV Solar. The attachment must be an attachment approved by the local building jurisdiction. Plans must indicate the attachment.
  3. ADDITIONALLY: If an art studio, pool house, or ADU is built over an existing garage, this is considered an addition to an existing structure. Not new construction. PV solar is not required. If an art studio, pool house, or ADU is built over a brand-new garage, (both being built as brand new), this is considered new construction and will require PV Solar.
  4. An unconditioned building converted to newly conditioned living space (such as a garage, shop, storage building) whether attached or detached to an existing conditioned low-rise residential building are ADDITIONS and are not required to have PV Solar (as it is not a newly constructed building).
  5. If a building department deems a "newly constructed" detached structure as an addition, the Title 24 Part 6 energy analysis can be calculated as an addition. Additions do not require PV solar under the 2019 Title 24 Part 6 Energy Code.

How to Prove the Exception for Shading

EXCEPTION 1 to Section 150.1(c)14: No PV is required if the effective annual solar access is restricted to less than 80 contiguous square feet by shading from existing permanent natural or manmade barriers external to the dwelling, including but not limited to trees, hills, and adjacent structures. The effective annual solar access shall be 70 percent or greater of the output of an unshaded PV array on an annual basis.

This exception is proved by using a Solar Access Tool approved by the CA Energy Commission. (The information below is from this Solar Access Tool link.)

The 2019 Building Energy Efficiency Standards (Energy Code) includes prescriptive requirements to install solar photovoltaic (PV) systems as a part of newly constructed low-rise residential buildings. As part of the PV requirement, builders must verify and document the shading conditions of the installed PV system as specified in Joint Appendix JA11.4. In particular, JA11.4(a) specifies that the verification must be done using a solar assessment tool that is approved by the executive director.

Contact a company that uses the CEC approved software to determine the building's SARA (Solar Access Roof Area). See list below of the CEC approved software providers. When that report is complete forward to CompuCalc or the CF-1R documentation author for review and possible recalculation of the CF-1R Energy Report.

Approved Solar Assessment Tools

The following solar assessment tools have been approved by CEC for use as specified in JA11.4(a):

CF2R Solar Access Verification

The CF2R-PVB-01-E, Certificate of Installation for Photovoltaic system requires a solar assessment report completed by an CEC approved solar assessment tool listed above. In addition, one of the following conditions must be met:

As always, I am available to discuss the process of meeting the California Energy Code for any building project. Contact me …