New and existing California programs are creating opportunities for multifamily, commercial and residential properties to take another look at solar thermal.

For California building owners, contractors, engineers and developers evaluating hot-water systems, there is a reason to look beyond the water heater itself.

Two California programs are putting renewable water heating directly into the conversation.

SoCalGas currently offers an energy-efficiency rebate for qualifying commercial and multifamily solar thermal collectors, while South Coast AQMD has approved a major expansion of its GO ZERO Incentive Program that adds zero-emission solar water heating to Phase 2.

For SunEarth customers and project partners, the message is simple:

If you have a building with a significant hot-water load, now is a good time to revisit whether solar thermal belongs in the system.

SoCalGas Business Rebates Already Include Commercial Solar Thermal

For commercial and multifamily projects, the most immediate opportunity is through SoCalGas.

Its 2026 Energy Efficiency Rebates for Business program specifically includes qualifying OG-100 certified solar thermal collectors for multifamily and commercial water-heating applications.

The current program lists an incentive of $120 per effective area of each qualifying collector, subject to SoCalGas program requirements, funding availability and project eligibility.

Eligible customer categories can include commercial, public, industrial and agricultural SoCalGas accounts.

That makes the program particularly relevant to applications with consistent hot-water demand, including:

• Multifamily housing

• Hotels and hospitality

• Healthcare facilities

• Food service and commercial kitchens

• Food processing

• Laundries

• Agricultural facilities

• Industrial hot-water and process applications

The program is not simply about replacing one appliance with another. For facilities with a substantial thermal load, it creates an opportunity to evaluate how much of that demand could be served by renewable heat before conventional heating equipment has to do the rest.

SunEarth manufactures ICC-SRCC certified solar thermal systems for commercial, multifamily and industrial applications and works with contractors, engineers and project teams to design systems around the building's actual hot-water requirements.

Important: Project eligibility and rebate amounts are ultimately determined by SoCalGas. The utility's current guide uses the wording "$120 per effective area of each collector," and project teams should confirm the applicable calculation with SoCalGas before incorporating a specific rebate value into a project budget.

South Coast AQMD Expands GO ZERO to Include Solar Water Heating

A second significant development is taking place through the South Coast Air Quality Management District.

On October 2, 2026, the South Coast AQMD Governing Board approved up to $60.2 million in additional funding for Phase 2 of the GO ZERO Incentive Program.

More importantly for the solar thermal industry, Phase 2 expands eligible technologies beyond heat-pump water heating to include zero-emission solar water heating for qualifying applications.

South Coast AQMD says the expanded program will provide additional funding for single-family and multifamily properties, with incentives prioritized in part toward overburdened communities.

For multifamily properties, the agency has announced rebate tiers ranging from $500 to $1,000 per unit, depending on the qualifying system and program criteria, with a property cap of $300,000.

The opportunity is especially relevant throughout South Coast AQMD's jurisdiction, which includes all of Orange County and major portions of Los Angeles, Riverside and San Bernardino counties.

However, the distinction matters:

The Phase 2 single-family and multifamily application portals are not yet accepting new applications. South Coast AQMD currently lists the relaunch as forthcoming.

Property owners and contractors should therefore begin identifying potential projects now while monitoring the agency for final application and reservation requirements.

Why This Matters for California Hot-Water Projects

California's energy conversation has increasingly focused on electrification.

But buildings do not consume technologies. They consume energy to meet loads.

And hot water is a thermal load.

In multifamily housing, hotels, healthcare facilities, restaurants, agriculture and industrial operations, that load can be substantial and recurring.

Solar thermal provides another way to address it.

A properly designed system can capture solar energy directly as heat and use it to preheat water before it reaches conventional or high-efficiency backup equipment.

That can reduce the amount of energy the primary water heater must provide without requiring the entire mechanical system to depend on a single technology.

Solar thermal can work alongside:

• Heat-pump water heaters

• Gas-fired backup equipment

• Electric water heaters

• Thermal storage

• Existing boilers

• Building controls

The design question becomes:

How much of the building's hot-water demand can renewable heat serve before the backup system needs to operate?

That is a different conversation from simply selecting a replacement water heater.

California Projects May Have More Than One Path to Consider

The SoCalGas rebate and South Coast AQMD GO ZERO program are separate programs with different eligibility rules.

Depending on the property, service territory, system design and final program requirements, a project may have access to one or more incentive opportunities.

South Coast AQMD has also stated that GO ZERO incentives may be combined with other eligible rebates and incentives, subject to the rules of the applicable programs.

That makes early project evaluation particularly important.

Before equipment is ordered or financial assumptions are finalized, owners and contractors should verify:

• Utility service territory

• Program eligibility

• Applicable solar thermal certifications

• Installation requirements

• Reservation or application timing

• Whether incentives can be combined

• Available program funding

Start With the Hot-Water Load

Incentives can improve project economics.

But they should not be the reason a system works.

The starting point should still be the building.

How much hot water is being used?

When is it being used?

At what temperature?

What is currently providing that heat?

How much thermal storage is appropriate?

And where can renewable heat reduce the amount of energy the primary heating equipment has to supply?

SunEarth has been manufacturing solar thermal equipment in California since 1978 and supports residential, multifamily, commercial and industrial water-heating projects across a wide range of applications.

For contractors, engineers, property owners and developers considering a California project, our team can help evaluate the thermal load, collector requirements, storage, controls and system configuration—and provide the certification and technical documentation needed to evaluate available incentive programs.

Have a California Hot-Water Project in Development?

If you're planning a multifamily, commercial, industrial or residential solar water-heating project, now is a good time to determine what incentives may apply.

Bring us the hot-water load. We'll help you evaluate where solar thermal fits.

Request a SunEarth Project Review

Additional resources:

Explore SunEarth Commercial Solar Water Heating

Explore SunEarth California Solar Thermal Solutions

South Coast AQMD GO ZERO Program

SoCalGas Business Equipment Rebates

Incentive programs, eligibility requirements, funding availability and rebate amounts are subject to change. SunEarth does not administer the SoCalGas or South Coast AQMD programs and cannot guarantee project eligibility or incentive payment. Applicants should verify current requirements directly with the applicable program administrator before making purchasing or project decisions.