The California Solar Initiative (CSI)-Thermal Program is a ratepayer-funded rebate program for customers of the four California investor-owned utilities (Pacific Gas and Electric, Southern California Edison, Southern California Gas and San Diego Gas & Electric). CSE is the program administrator for the SDG&E territory.
The CSI-Thermal Program will run through December 31, 2019, or until rebate money runs out. For comprehensive program details and requirements, please see the California Solar Initiative (CSI) -Thermal Program Handbook. Following are some of the basics.
- Customer Eligibility
Single-family Residential
The CSI-Thermal Program offers cash rebates to single-family residential customers who
- Heat their water with natural gas*
- Install a qualifying solar water heating (SWH) system
- Are customers of one of the four designated investor-owned utilities in the state
Single-family customers must directly use the hot water from the SWH system.
NOTE: Space heating, space cooling and swimming pool or spa heating are not eligible uses for single-family properties.
* Residential CSI-Thermal rebates are no longer available for electric- or propane-displacing systems.
Multifamily Residential & Commercial
The CSI-Thermal Program offers cash rebates to multifamily residential and commercial customers who
- Use a solar thermal system to offset natural gas consumption*
- Install a qualifying solar thermal system
- Are customers of one of the designated four investor-owned utilities in the state
Commercial and multifamily customers can receive a rebate for a SWH system and other solar thermal systems installed for process heat, space cooling, space heating, pool heating or any combination.
Examples of rebate-eligible businesses include commercial laundries, gyms, laundromats, restaurants, convalescent homes, hotels/motels, school dormitories, prisons, agricultural processes, hospitals, food processors, wineries, breweries, car washes and other applications.
* CSI-Thermal rebate funds for electric- or propane-displacing multifamily and commercial systems within the SDG&E service territory are nearly expended and applications will be put onto a waitlist.
- Solar Thermal System Requirements
Solar thermal systems must be rated by the Solar Rating and Certification Corporation (SRCC) or the International Association of Plumbing and Mechanical Officials (IAPMO).
- Single-family residential systems must have OG-300 certification
- Commercial/mulitfamily collectors must have OG-100 certification
- System installations must conform to manufacturers' specifications and all applicable codes and standards
- All systems must have freeze and overheat protection
- Rebate Amounts
Rebates are calculated based on expected performance for the specific solar thermal system for one year.
Single-Family Residential
Natural gas-displacing systems: $4,366 maximum
Commercial/Multifamily
Natural gas-displacing systems: $800,000 maximum
Natural gas-displacing solar pool systems: $500,000 maximum
Check current funding status at www.csithermal.com/tracker.
Low Income
Higher rebates may be available for single-family and multifamily natural gas customers.
- Single-family low income: $5,397 maximum
- Low-income multifamily properties may qualify for a higher incentive rate.
For information, see the Low-Income User Guide.
- Rebate Structure
The CSI-Thermal Program has a step-down incentive structure. There is a step budget for each general market customer class and service territory. As more projects are installed, the rebate levels decrease. The low-income program has a total budget, not a step budget, and steps down when the general market program steps down.
To see the current rebate status, visit the CSI-Thermal Tracker at www.csithermal.com/tracker.
Single-Family Natural Gas-Displacing System Rebate Steps
| Step | Rebate per annual therm displaced | Maximum rebate |
| 1 | $29.85 | $4,366 |
| 2 | $25.37 | $3,710 |
| 3 | $14.30 | $2,091 |
| 4 | $3.23 | $472 |
Multifamily/Commercial Natural Gas-Displacing System Rebate Steps
| Step | Rebate per annual therm displaced | Maximum rebate |
| 1 | $20.19 | $800,000 |
| 2 | $17.16 | $800,000 |
| 3 | $10.15 | $800,000 |
| 4 | $3.13 | $800,000 |
Multifamily/Commercial Solar Pool Rebate Steps
| Step | Rebate per annual therm displaced | Maximum rebate |
| 1 | $5.00 | $500,000 |
| 2 | $5.00 | $500,000 |
| 3 | $4.00 | $500,000 |
| 4 | $3.00 | $500,000 |
Single-Family Low-Income Rebate Steps
| Step | Rebate per annual therm displaced | Maximum rebate |
| 1 | $36.90 | $5,397 |
| 2 | $32.42 | $4,741 |
| 3 | $21.35 | $3,122 |
| 4 | $10.28 | $1,503 |
Multifamily Low-Income Rebate Steps
| Step | Rebate per annual therm displaced | Maximum rebate |
| 1 | $24.89 | $800,000 |
| 2 | $21.86 | $800,000 |
| 3 | $14.85 | $800,000 |
| 4 | $7.83 | $800,000 |
- Application Process
As the installer, you are responsible for submitting the rebate application and required paperwork for your customer or for yourself if you are a self-installer. After you complete the workshop “How to Become an Eligible Contractor in the CSI-Thermal Program,” you will receive a unique registration key. You can then visit www.csithermal.com to complete the online application. To find out when the next scheduled workshop is taking place, check CSE’s events listings.
Single-family rebates are applied for and paid after system installation and inspection by the appropriate authority having jurisdiction. All systems are required to get a permit from the appropriate city or county. Rebates are calculated based on expected performance for the specific SWH system. Program calculators are publicly available and embedded in the application database. A check will be sent to the payee indicated on the Incentive Claim Form after all documents are approved and a program inspection is completed (if required).
Multifamily and commercial solar water heating and solar pool systems also receive a one-time payment after the system has been installed and inspected. Rebates are calculated based on expected performance for the specific SWH system. Program calculators are publicly available and embedded into the application database.
Multifamily and commercial systems that involve other end uses (e.g., process heat) will receive a performance-based incentive that is paid based on metered data over two years.
Once the rebate application is completed and submitted online through an automated database, we proceed with the following application processing.
- Single-family applications: These projects go through a one-step application process. The contractor submits the necessary documentation to the CSI Thermal application database after the SWH system has been installed and inspected by the local building department. Program staff will review the application for accuracy and if all the information is correct, the application will either be approved for payment or sent to inspection.
- Multifamily and commercial applications: These projects go through a two-step application process. Once a contract agreement has been signed, the contractor may submit an application to reserve rebate funding for the project. This application will be reviewed and if approved, the contractor will have 18 months to complete the project and submit the Incentive Claim Package before the reserved rebate funding is released. Once installation is complete, the contractor will have the opportunity to edit the system to reflect the “as-built” specs before submitting for final program review.
For more information and resources, view our CSI-Thermal Installer Toolkit.
- Tax Credits Available
In addition to rebates offered through the CSI-Thermal Program, you may also be eligible to claim a federal solar tax credit for up to 30% of the cost of your/the new solar system, including equipment and installation. Combined with the CSI-Thermal rebate, this can make a huge difference in how much solar water heating will cost out of pocket.
For questions regarding the federal investment tax credit, customers should speak with a tax professional. For general information regarding the Residential Renewable Energy Tax Credit and the Business Energy Investment Tax Credit, visit DSIRE.