The 2020 Solar Mandate Broken Down

(Last modified on January 26th, 2022.)

The announcement of the 2020 solar mandate made quite a buzz and by now, most everyone has heard of it.

The mandate will require all new construction and buildings undergoing additions and alterations in the state of California to have solar starting this year. It applies to all single and multifamily dwellings, three stories or fewer.

But what exactly does that mean? How much solar will each construction need to comply? How are properties with shade concerns affected? And how will developers keep their homes affordable?

We read through the Community Environmental Council’s (CEC) Manual and did some research to clarify some point and answer the above questions.

How much solar will one need to comply with the 2020 mandate?

According to the CEC’s Residential Compliance Manual for the 2019 Building Energy Efficiency Standards, the minimum qualifying size of the PV system is based on the projected annual electrical usage of the building. The CEC provides us with an equation (on pg 7-1) that essentially states that a dwelling’s rooftop annual solar output must be equal to or greater than the dwelling’s annual electric usage.

Using these calculations, Green Tech Media predicts that “the average system size across California’s 16 climate regions would be 3.38 kilowatts, with the smallest model system sized at 2.7 kilowatts in San Diego and the largest sized at 5.7 kilowatts in Palm Springs.”

Despite these size restrictions, some projects may qualify for an exemption.

What are the solar mandate exemptions?

Exemptions are covered in section 7.6.2 of the manual. Below is a succinct list of possible exceptions or system size reductions:

• Seasonally occupied and temporary structures are exempt.
• If pre-existing natural or manmade shading issues exist and there is less than 80 contiguous square feet solar access area, solar is exempt.
• For two story, three story or higher residential buildings, the required PV system size may be reduced if there is inadequate roof space, but to no less than 1 or .8 Watt DC per square foot, respectively.
• For buildings with battery storage the required PV size may be reduced by 25%. For single family dwellings, the minimum battery storage must be at least 7.5kwh. For multi-family dwellings, the battery storage must be 7.5kwh per dwelling.
• For residential projects approved by the planning department before 1/1/2020 with available roof top solar space, the PV size “is limited to the lesser of the size that can be accommodated by the effective annual solar access.”

If the project qualifies for one of the exceptions above, it must still comply with the ‘solar ready’ requirement. This requirement states that a solar zone must be designated where solar panels can be installed at a future date – if the owner chooses to do so. The following are exceptions to the solar zone rule (more on this can be found in section 7.6):

• If a solar-water heating system (that complies to guidelines) is permanently installed at the time of construction,
• If a single-family-home has 3 or more habitable stories and a total floor area of 2,000 square feet or less, the solar zone may be reduced,
• If a single family home is located in the Wildland-Urban Interface Fire Area, the solar zone may be reduced to 150 square feet or greater,
• If the roof of a single-family building is shaded by objects that are not part of the building and out of the designer’s control, so that the potential solar zone is 50% or less.

If one of the above exemptions could apply, the appropriate documentation must be provided to the building department with the building permit application.

Will the mandate make new homes unaffordable?

While many argue that the added purchase cost of solar homes will keep households from buying a home, BayWa r.e.’s Jonah Liebs argues that many builders are already including third party financing on their new constructions to mitigate this issue. Although in the long term the return on a system with such financing is much lower than one purchased with cash, it does allow builders and homebuyers to install solar with zero cost up front.

Abigail Ross Hopper, president and CEO of Solar Energy Industries Association, adds that in the end it will come down to what the customer wants. Developers have the flexibility of rolling “the development costs into a mortgage, offer the customer a lease, or present another type of financing product.”

Additionally, the 2020 solar mandate incentivizes solar-plus-storage solutions, giving home developing firms another method of reducing the required size and cost of the solar installation if it’s paired with a energy storage solution.

Jack Flemming of the LA Times indicated that “for some, salvation may lie in the mandate’s allowance for ‘community-shared solar options,’ which could translate to off-site solar farms that would send the energy to the homes via transmission lines. This option would require a bit more planning — as developers would have to buy land for the farms and find a way to distribute it — but could save both sides a small fortune.”

Sacramento County already has a large scale community shared solar option that is set to launch this year. Through this program, new homeowners will receive solar energy from a system built and maintained by the district of Sacramento.

California Building Industry Association Chief Executive Dan Dunmoyer “estimates that these farms could lower the cost per home from $8,400 to $1,200 thanks to economies of scale.”

Potential home energy savings & effect on the solar industry

The 2020 solar mandate is part of California’s net zero emissions by 2045 goal and makes great strides toward cutting emissions in half by 2026. The mandate is predicted to reduce residential electricity bills by over 50%, saving Californians $1.7 billion in energy costs over the next 30 years.

Solar installations across the state are projected to increase four-fold, if California’s new home construction trend continues at 80,000 new homes per year. It’s expected that with the rise of public awareness, solar sales for existing homes will also increase.

To hear more about the 2020 solar mandate, check out our CEO Cecilia Villaseñor Johnson and Wesly Johnson, installer, discuss it in this interview.