Several factors impact the amount of solar that new low-rise residential construction projects will have to install under the new 2019 California Energy Code, and knowing how these factors affect solar budgets may result in more efficient and cost-effective design. Below are VCA Green’s top 5 things to know about the 2019 solar mandate.

  1. Climate Zone will impact the amount of PV your building requires. Projects in “extreme” climate zones – those located in northern latitudes, high elevations, or inland deserts – will need to produce more kilowatt-hours from photovoltaics (PV) in order to offset the higher energy usage anticipated by the California Energy Commission (CEC).
  2. Unit Size and Quantity also have significant impacts on required kilowatt-hours of PV. Each dwelling unit increases the annual generation requirement by anywhere between 1500 and 3000 kWh, depending on square footage. Likewise, increasing dwelling unit size increases PV required, with roughly 1 kWh needed for each additional square foot. Determining a balance between unit size and quantity will impact the number of kWh a system will need to produce. For example, a 1000 sq. ft. unit will require between one- and two-thousand fewer annual kilowatt-hours of PV than two 500 sq. ft. units. Based on the CEC’s calculation methodology, architects and developers may consider analyzing the first-cost implications of unit size and quantity versus required PV system size.
  3. Battery Storage Systems may be used to reduce the required PV size by 25%. Single family batteries must be at least 7.5 kWh total, while multifamily buildings must have a capacity of 7.5 kWh per dwelling unit. Both must be coupled with a PV system in order to qualify for the reduction in size credit. In addition to the size credit, installing battery storage allows the system to reduce utility costs by capturing energy during the day when electricity rates are low, and utilizing it in the evening, when consumption and rates increase.
  4. Community Shared Solar may be an alternative to installing solar PV on site. While the CEC is still determining where sites can purchase solar power from (more information here), community solar offers owners and developers an alternative path to complying with the solar mandate. The energy savings benefits to each building must be in the form of actual reductions in energy consumption, utility energy reduction credits, or payments to the building that would result in equivalent benefits to the other two options.
  5. Exceptions are in place to help projects with extreme circumstances meet the code’s intent. Projects with less than 80 sq. ft. of unshaded roof space are not required to install PV. Additionally, buildings in Climate Zone 15, two-story residential buildings, and three-story or higher residential buildings may reduce their system size using alternative calculations specified by the Energy Code if they have inadequate roof space to accommodate the PV calculated by the standard equation.

Navigating new code requirements can be a time-consuming challenge for project teams. VCA Green has a team of Energy Code and solar experts who can assist in removing the red tape and turning ever-changing code requirements into energy- and cost-saving opportunities. For more information on the 2019 Energy Code’s solar mandate or CALGreen and Energy Code consultation services, please contact Moe Fakih below.

Contributing Writer: Luca Costa, Assistant Project Manager

Moe Fakih, Principal
VCA Green
714-363-4700 x501