California’s Title 24 is Fast Approaching

January 1st, 2020 will bring major changes to the way homes are built in California. In December of 2018, the California Building Standards Commission approved the state’s Title 24 Building Energy Efficiency Standards. This edition of building standards for the state requires unprecedented efficiency upgrades, including a solar mandate for most new homes.


Building permits pulled in 2020-2023 for any home that’s three-levels or lower will be required to accommodate solar panels unless the home qualifies for an exemption. Even if a home qualifies for an exemption, it is still required to reserve a section of roof space called a “Solar Zone,” in case the homeowner should need or want to install solar in the future.


The 2019 standards were developed by the California Energy Commission (CEC), and the photovoltaic requirement isn’t the only upgrade from the previous 2016 building requirements. The CEC also updated the standards for the way attics, walls, water heating, and lighting are built and installed. Taking these steps to ensure homes are being built as energy-efficient as possible will help California work closer to its Renewable Portfolio Standard of 60% renewable energy by 2030 ( 


Solar Array Size Depends on a Number of Factors

The CEC was required to develop a solar mandate that would save California homeowners money over the course of 30 years. This was a complicated task since home size, climate, and electricity costs vary greatly throughout the Golden State. The CEC’s resolution comes in the form of an equation that enables solar professionals to calculate the minimum size photovoltaic system required for a given property. The different factors of the equation accommodate for the variability between home size and region.


kWPV required = (CFA x A)/1000 + (NDwell x B)

Equation Result:

kWPV stands for the required amount of kWdc, or electrical output, the PV system must produce for the home.


Equation Factors:

CFA stands for Conditioned Floor Area, or the amount of square footage of the home.

NDwell stands for the number of livable units within the building.

A stands for the Adjustment Factor of the Climate Zone where the house is located. There are 16 Climate Zones in the state.

B stands for Dwelling Adjustment Factor. There are also 16 values for this factor.


Some Buildings May Be Exempt

The standards offer six exceptions for homes that lack adequate roof space or suffer substantial shading from a preexisting and unavoidable structure. A home’s solar panels have to receive 70% or more of the sunlight that an unobstructed array in the same Climate Zone would receive to be considered and effective PV system.


Exemption 6 sets forth an opportunity to install battery storage, which provides the option to reduce the necessary size of a PV system by 25%. The minimum capacity for a battery storage system to qualify is 7.5 kWh per dwelling.


Economic and Environmental Benefits of Title 24

California stands to gain significantly from the Title 24 Standards in a number of ways. According to a CEC publication, CO2 emissions will be reduced by 700,000 metric tons over the three-year cycle of the new standards. Also, the CEC worked with a consulting agency for three years to determine how the solar requirement could produce long term savings for every new home. Based on a 30-year mortgage, the CEC estimates the new standards will reduce energy costs associated with heating, cooling, and lighting by $80 per month, while only adding $40 per month to the homeowner’s mortgage. 


California is also working towards improved grid harmonization by encouraging the adoption of battery storage and restricting the direction that solar panels can be angled. This aligns a home’s solar production its time of energy consumption, resulting in grid stabilization and less energy lost through transmission. Consuming solar energy onsite is the way of the future for homes and California is leading the way.