If you’re a California resident, you’ve likely heard of the California Solar Mandate. It affects both new construction and home renovations, in an attempt to bring greener energy to the state.
Confused about the requirements for this program? That’s why we created this guide, which includes:
- The basics of the California Solar Mandate and some of its perks
- What types of homes are affected by the California Solar Mandate
- What is the best roofing material for installing solar panels
If you are required to install a solar system on your roof, you’ll want to have this vital information to make the best decision about roofing materials to get the most out of your panels.
What Is the California Solar Mandate?
The California Energy Commission upgraded its energy efficiency standards in 2018, requiring that all new residential construction projects have solar photovoltaic (PV) systems installed on the roof starting in 2020. This California Solar Mandate was intended to decrease the number of homes relying on natural gas in favor of cleaner energy sources. Another result would be to reduce pollution in the state. The overall goal is for California to generate 50% of its electricity from renewable sources by 2030.
The California Solar Mandate was updated in 2023 to broaden the types of buildings requiring solar panels. Now, apartment buildings over three stories tall and many types of commercial buildings require PV systems, including:
- Schools
- Warehouses
- Offices
To make the California Solar Mandate both more practical for homeowners and better for the state’s energy efficiency, a number of features were included in the plan:
- Homeowners must use the solar energy they generate, not export it for profit or utility bill reduction.
Batteries should be used primarily at night, when the demand for electrical energy from the grid is higher. - Early adopters of solar energy systems before 2026 receive a Federal Investment Tax Credit to help offset installation costs.
- Property value is increased because of the solar panels, but until 2027, homeowners will not see this reflected in higher property taxes.
Is Your California Home Affected by the Solar Mandate?
Who Is Required to Install Solar Panels?
If you are building a property that is a single-family home, duplex, or condo/apartment building, it probably needs to include solar panels to comply with the California Solar Mandate. Likewise, homes undergoing major renovations must also have PV systems installed.
There are three exceptions to this requirement:
- Properties with a roof that is too small for solar panels
- Homes where the roof is heavily shaded and doesn’t get sufficient sunlight for solar
- Properties that have access to community solar power
What Are the Energy Requirements of the California Solar Mandate
Any solar energy system that is installed on a home must at least meet the home’s energy needs. As new properties have yet to be occupied, meaning the users’ energy needs are unknown, two factors are used to determine the energy needed:
- The square footage of the property
- Where in California the home is located
Furthermore, using a battery can reduce the amount of energy a solar system requires by up to 40%. This is a significant amount of storage, so if your battery has a storage capacity of 7.4kWh or more, the size of the solar system can be reduced by 25%. Batteries to store solar energy are also beneficial during public safety shutoffs by electrical utilities seeking to reduce risks during peak wildfire periods.
What Type of Roof Is Best for Solar Panels?
Whether you’re building a new property or renovating an existing one, it’s important to understand that not all roofing can handle the installation of solar panels. And there are other considerations that make evaluating your roofing material essential. Here are four things to think about to help you choose roofing for new construction or a roof remodel that’s part of a home renovation.
Roofing Material Lifespan
Imagine you have asphalt shingles on your roof, as many homes do. They need to be replaced about every 12 years. However, solar panels have an average lifespan of 25 years. What happens when your shingles need replacement? You have to shoulder the expense and hassles of removing and reinstalling your solar panels before and after your roof remodel.
A better solution is to install metal roofing. It lasts two to three times longer than conventional roofing materials, including clay tiles and wood shakes. That gives you about 40 to 70 years without having to replace your roof—more than most folks are in their home.
Weight of the Roofing Material
Solar panels are heavy, averaging about 40 pounds each in weight. An average home needs 15-21 solar panels, or more if the occupants’ needs are higher. That translates to a minimum of 600 additional pounds on your roof. Can your roof handle it?
If you already have weighty roofing material, like clay or cement tiles, the answer may be no, unless you install reinforcements below the roof. Also, if you have a weak roof, whether due to cheap shingles or weather damage, it may not be able to support a solar system. Wood shakes are lightweight, but not the sturdiest, and they’re not recommended or even banned for some high fire risk areas in California.
The answer is to install metal roofing. At well under 2 pounds per square foot, it’s lighter than other options.
Load-Bearing Capacity of the Roof
Lighter roofing doesn’t necessarily mean weaker. In fact, metal roofing, like DECRA stone-coated metal roofing, has a high load-bearing capacity. It can handle the weight of solar panels without sagging, which is why it’s so popular in cold climates that see heavy snowfalls, which includes mountainous areas of California.
Solar Reflectivity and “Cool Roofs”
The heat of a roof affects the functionality of solar panels. For every degree above 77 degrees Fahrenheit, solar panels lose 0.45% in efficiency. So, if you live in Southern California, especially inland, you could experience a quantifiable loss of solar power on hot days, which is much of the year.
That’s why in some areas, the California Solar Mandate requires homeowners to use “cool roofs” that reflect the sun’s rays rather than absorbing them. Unlike asphalt, which can reach 150 degrees on a hot day, DECRA metal roofing keeps the roof temperature stable. This meets the requirements for a cool roof and also helps property owners mitigate cooling energy use during warm weather.
Adding Solar Panels? It’s the Perfect Time to Install a DECRA Metal Roof
Are you building a new home or planning a roof remodel as part of a renovation? Now is the time to start thinking about the right roof for your solar system as required by the California Solar Mandate.
We invite you to check out DECRA stone-coated metal roofing, so you can see how lightweight and durable it is. Just request a complimentary sample to be sent to you.
It is available in a range of colors and profiles that look just like traditional shingles, shakes, and tiles to match every home style. And with its superior weather protection and long-term financial benefits, it’s the perfect choice for your California roof.
Editor’s Note: This blog was originally published in February, 2023, but has been updated with relevant information.
