As noted previously, for the 2019 Title 24 code, the PV requirement is a new prescriptive requirement for newly constructed single-family and low-rise multifamily buildings. However, there are multiple exceptions to the photovoltaic requirements, listed below:
Exception 1: May apply if there is limited unshaded roof space. 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.
Exception 2 may apply to climate zone 15 and the required PV size may be reduced, if there is inadequate space on the roof to accommodate the PV size specified in Section 7.2.1 of the 2019 CA Energy Code.
The PV size shall be the smaller of a size that can be accommodated by the Effective Annual Solar Access Roof Areas, or a PV size required by the equation above, but no less than 1.5 Watt DC per square foot of conditioned floor area.
Exception 3 may apply to two stories residential buildings and the required PV size may be reduced if there is inadequate space on the roof to accommodate the PV size specified in Section 7.2.1 of the 2019 CA Energy Code.
The PV size shall be the smaller of a size that can be accommodated by the Effective Annual Solar Access Roof Areas, 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 may apply to three stories or higher residential buildings and the required PV size may be reduced if there is inadequate space on the roof to accommodate the PV size specified in Section 7.2.1 of the 2019 CA Energy Code.
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 Roof Areas, 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 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 may apply to buildings with battery storage system. The required PV sizes from Equation 7-1 (found in Section 7.2.1 of the 2019 CA Energy Code) may be reduced by 25 percent if a battery storage system is installed.
For single-family buildings, the minimum capacity of the battery storage system must be at least 7.5 kWh.
For multifamily buildings, the battery storage system must have a minimum total capacity equivalent to 7.5 kWh per dwelling.
In all case the battery storage needs to meet the qualification requirements specified in Joint Appendix JA12 and be listed with CEC.
Definitions
Annual Solar Access: The annual solar access is the ratio of solar insolation including shading over the solar insolation without shading.
Effective Annual Solar Access: The effective annual solar access shall be 70 percent or greater of the output of an unshaded PV array on an annual basis.
Effective Annual Solar Access Roof Areas: Are roof areas that meet the Effective Annual Solar Access requirements and are at least 80 contiguous square feet.
C&S Energy Pro is committed to getting a fast turnaround on your Title 24 documents which will help ensure construction projects are completed on time and that consumers will be able to move into their homes quicker. Avoid the hassle of long wait times generally associated with Title 24 documentation and call us today!