Zero-emission Space and Water Heaters - Frequently Asked Questions (FAQs)

Contact

Last updated January 27, 2026.

Motivation

Why is a regulation being considered?

Zero-emission space and water heater standards would help reduce pollution that causes climate change, such as carbon dioxide (CO2), methane (CH4), and nitrous oxides (N2O). The regulation would also lower harmful air pollution like nitrogen oxides (NOx), particulate matter (PM), carbon monoxide (CO), and other toxic chemicals. Reducing GHG emissions will help California reach its climate goals in the 2022 Scoping Plan. It will also help California meet State and federal air quality standards, improve air quality, and help protect people’s health.

More about benefits

Concept for Regulation

Can I still own a polluting space and water heater after 2030, or will I need to replace it before then?

Yes, you can still use or repair your existing space and water heaters after 2030. This potential rule would not require people to replace their working heating equipment. Instead, manufacturers would have a limit on the number of GHG emitting space and water heaters they can sell in California.

Defining Zero-Emission

What do you mean by a zero-emission standard? What emissions would be regulated? Do these include NOx and CO?

We are considering defining “zero-emission” for space and water heaters as producing zero greenhouse gases (GHG) during use. This would include emissions such as carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). Technologies that meet this definition include electric resistance, heat pumps, solar thermal heaters, and others developed in the future.

While the focus is on lowering GHG pollution, we are also evaluating potential air quality and health benefits. These include reductions in emissions of smog-forming nitrogen oxides (NOx), carbon monoxide (CO), and toxic air contaminants.

CARB may also consider a separate regulation to lower hydrofluorocarbons (HFCs) emissions from refrigerants used in water heaters and other heat pump applications. CARB already regulates the global warming potential (GWP) of refrigerants in space conditioning equipment and may expand those requirements to other heat pumps. This work will be guided by directives such as California’s carbon neutrality goal and Senate Bill 1206.1

Scope of the Regulation

What is the scope of this potential regulation? Which space and water heaters would this regulation apply to?

The main goal of this rule is to lower greenhouse gas pollution from new space and water heaters sold in California for use in homes and businesses.

Would this potential regulation apply to propane space and water heaters as well?

We will evaluate whether propane space and water heaters should be included in potential rule during the rulemaking process.

Would this potential regulation apply to space and water heaters used in residential and/or commercial buildings?

The potential zero-emission standards would apply to all new space and water heaters sold for use in both homes and businesses.

Would this potential regulation apply to multi-family unit housing and high-rise condominiums?

The potential zero-emission standards would apply to all new space and waters heaters sold for both single-family and multi-family residential buildings. This includes high-rise condominiums.

Would there be any exceptions based on income, geographic location, or climate zone?

During the rulemaking process, we will explore considerations such as cold climate conditions, electric grid issues, and the cost of building upgrades needed to install zero-emission heating equipment.

Timing for the Regulation

Is the regulation finalized? Can the public comment on this process?

The regulation has not been finalized. We have not yet submitted a formal regulatory proposal to the CARB Board for consideration. Public engagement for the regulatory concept began in 2023. You are encouraged to participate in the regulatory development process. CARB will host public meetings and individual meetings with interested parties to gather input and refine the proposal. The public will also have the opportunity to provide feedback on the preliminary regulatory language. These events provide opportunities for individuals, businesses, and organizations to share feedback and ask questions. To receive the latest news about upcoming meetings and comment opportunities, you can sign up for CARB’s 'Building Decarbonization' email list.

Is a faster timeline something CARB will consider?

Yes. We are evaluating whether the rule should start around 2030 or sooner in some cases. The timeline will depend on what we learn during our technical analysis, public input, and equity considerations gathered during the rulemaking process.

Complementary Policies and Local and Regional Efforts Underway

How would this potential regulation align with other building decarbonization efforts in California?

The potential rule is an important part of California’s larger building decarbonization strategy. The goal of building decarbonization is to make buildings healthier, more energy-efficient, and better for the environment, while ensuring the process is fair and affordable for everyone.

This rule is intended to complement other supportive building policies, including:

  • Reducing fossil gas infrastructure expansion,
  • Promoting zero-emission new construction,
  • Expanding access to incentives,
  • Ensuring fair energy prices,
  • Training a skilled workforce,
  • Increasing public awareness of clean options.

Why is this regulation needed instead of focusing on new construction codes?

While new construction codes are important, they only affect a small portion of buildings. Each year, California adds about 112,000 new homes2  and over 100 million square feet of new commercial buildings.3  Yet, there are about 14 million existing homes and over 7.5 billion square feet of existing commercial buildings in the state.4

CARB staff support new construction codes. But to help California reach its climate goal of carbon neutrality by 2045 or sooner, the state also needs to cut pollution from existing buildings. This is part of California’s climate plan in the 2022 Scoping Plan and is needed to meet federal air quality standards.

How would this potential state regulation fit in with local air districts’ zero-emission space and water heater standards?

CARB’s potential zero greenhouse gas emission rule for new space and water heaters would work alongside, not conflict with, local air districts rules. If CARB’s rule is adopted by the Board, manufacturers would need to comply with both CARB’s rule targeting greenhouse gases and the local air district rules targeting nitrogen oxide (NOx) emissions.

The Bay Area Air District (Bay Area) approved amendments to Rules 9-4 and 9-6. These rules apply when new space and water heating equipment is sold. They require that the equipment meets zero-NOx emission limits. Small water heaters made on or after January 1, 2027, must be zero-NOx emission to be sold in the Bay Area. All space heaters manufactured on or after January 1, 2029, need to meet zero-NOx emission limits. Larger water heaters must also be zero-NOx starting in 2031.

In June 2024, South Coast Air Quality Management District (SCAQMD) passed amendments to Rule 1146.2. This rule sets zero-NOx emission limits for large water heaters, small boilers, process heaters, pool heaters, and high temperature heaters. Amendments to Rules 1111 and 1121 are also being updated to include zero-NOx emission limits. Rule 1111 covers smaller space heaters and Rule 1121 covers water heaters.

Costs and Incentives

How do zero-emission space and water heater prices compare to natural gas or other space and water heaters?

Zero-emission space and water heaters usually cost more to purchase than polluting equipment. This initial cost includes the cost to buy and install the equipment. Installation needs vary depending on the building. Factors include the type of heater and whether you need to update the building space, electric panel, or utility connections. If the electric panel needs more capacity, the utility company may also need to upgrade equipment such as the wiring or meter that brings power to the building.

There are several incentives and tax credits for buying and installing zero-emission heaters that can lower costs. See below.

What kind of financial help is available, especially for people with lower incomes?

There are several rebates, tax credits, and financing programs that can lower the cost of buying and installing zero-emission heaters. These incentives are provided by State of California, California Air Districts, utilities, and others. Available incentives include:

The Switch is On Incentive Finder is a helpful tool to find available federal, State, and local incentives by ZIP code.

CARB will continue relying on partner public agencies to run programs that help low-income households buy and install zero-emission space and water heaters.

Will CARB consider incentive programs to help cover structural costs of retrofits such as upgrading or replacing old ductwork or intake vents in homes that are either aging, leaking, or do not work well with modern heat pump systems?

As part of our cost analysis, CARB will review how much money is set aside for incentive programs. We will also look into which existing incentive programs have funding for replacing old ductwork and vents and making buildings more energy efficient with weatherproofing. Weatherproofing means keeping outside air, moisture, and temperature changes from getting inside a building. This helps lower energy bills.

How would this potential regulation impact energy bill costs? And how would energy bill costs influence this regulation?

Energy bills for space and water heating depend on the cost per unit of energy (or the energy rate) and the efficiency of the heaters used. 

Currently, electricity tends to cost more per unit compared to natural gas. Yet some technologies, such as heat pumps, are much more energy efficient than polluting heaters or even electric resistance heaters. This higher efficiency can result in lower operating energy costs over time. Heat pump space heaters also provide both heating and cooling. This can make them a cost-effective option for buildings that need both.

Supportive energy pricing is important to making building decarbonization more affordable. The California Public Utilities Commission (CPUC) has made changes to energy rates based on California Assembly Bill 205. These changes include a new fixed monthly charge on electric bills for California IOUs. This change moves the cost of maintaining the electric grid out of the per-unit energy price and into a flat fee based on household income. The billing change lowers the per-unit cost of electricity for all customers and helps make zero-emission equipment and vehicles more affordable. The new billing structure goes into effect late 2025 and early 2026. Public utilities, Community Choice Aggregators (CCAs), and smaller energy companies also need to develop energy prices that help support cleaner buildings.

Low-income households may qualify for energy bill discounts through the California Alternate Rates for Energy (CARE) program. Households with slightly higher incomes may qualify for the Family Electric Rate Assistance (FERA) program.

We are analyzing how much it costs to use zero-emission heaters compared to traditional polluting systems. These cost comparisons are a key part of our analysis as we develop new rules to reduce pollution from buildings.

If Californians reduce gas usage for water and space heating, do you expect gas prices to increase for those still using gas?

CARB staff are analyzing the cost impacts for households and businesses, including utility bill changes. We rely on the California Public Utilities Commission’s programs focused on energy rate design to support cleaner, less polluting buildings. It is uncertain how much gas prices will change over time and how much energy bills may change for customers continuing to use gas.

Electrical Grid Capacity

How can CARB make sure the grid will be ready before the increase in electrical demand? Will CARB set any minimum grid standards or prerequisites (e.g., stress test, etc.) to make sure the grid is ready? 

CARB does not plan to set greenhouse gas heating standards dependent on the grid, but we will consider if exceptions are needed for areas where the grid isn't ready or doesn’t have sufficient electric infrastructure. We will ask for public input on this during the rulemaking process.

CARB collaborates with energy agencies that plan the electric grid through the Integrated Energy Policy Report (IEPR) process. The goal is to make sure they are planning for future electricity needs as more people use zero-emission space and water heaters (and vehicles). The IEPR forecasts include the extra electricity needed for zero-emission space and water heaters. The CPUC and electric utilities then use this forecast to help plan the power grid. As the 2022 Scoping Plan explains, there is a broader effort to help the electricity grid grow faster than ever before while keeping the grid reliable, affordable, and resilient for the next 20 years and beyond.

Is there enough electricity for more zero-emission space and water heaters, along with other technology such as electric vehicles?

California is building and improving the power grid to make sure there’s enough electricity for the growing demand. State and utility forecasts and plans for the power grid include more zero-emission electric space and water heaters, as well as electric vehicles.

The California Energy Commission (CEC) expects electricity use across the state to go up by about 28% between 2023 and 2035. This includes using more electricity for zero-emission space and water heaters and electric vehicles.5 To meet this growing demand, the state is planning to add a lot more renewable energy and battery storage. It plans to build 72 gigawatts of solar power and 37 gigawatts of battery storage by 2045.6

Some newer neighborhoods in my community have underground wiring, and the connections to homes might not be able to handle more demand for electricity. Is there a way to address this?

Underground wiring shouldn’t impact newer neighborhoods from being able to add more electricity. In fact, most newer neighborhoods are made with sufficient wiring, service connections, and panel space to handle the extra electricity needed to install electric equipment. Since 2015, most new single-family homes in California have been built with a 200-amp electrical service panel.

The 2025 Energy Code requires the main electrical service panel in single-family homes to have at least a busbar rating of 200 amps. The 2025 Energy Code also includes “electric-ready” rules for new single-family and  apartment buildings. It requires wiring and enough space in the main electrical service panel to be able to install zero emission equipment in the future.  The 2025 Energy Code also includes provisions to encourage the installation of heat pumps for both space and water heating in newly constructed single-family, multifamily, and select nonresidential buildings.

There are new ways to accommodate zero-emission heaters in existing buildings that don’t have adequate wiring, service connections, or electric panel space. They include smart panels, automatic load management, and power-sharing devices. These tools make it easier to use zero-emission space and water heaters without having to upgrade the wiring, electrical panel or panel space.  

Residential Building Retrofits

Do zero-emission space and water heaters need more space?

In most homes, especially single-family homes, space is not a barrier to installing zero-emission space heating systems. There are many types of systems available to fit different layouts and needs, including:

  • Ductless mini-split systems,
  • Packaged systems,
  • Electric resistance furnaces, and
  • Packaged terminal heat pumps.

For homes that already have air conditioning, a zero-emission heat pump system can often replace both the furnace and air conditioner. These systems fit in the same space as the current furnace and air conditioner while providing both heating and cooling.

Zero-emission water heaters, such as heat pump water heaters, may need more room than polluting ones because they require more airflow and bigger tanks. Most heat pump water heaters are made to fit in the same space as polluting ones but might sometimes need to be moved to a larger area.7  To address space challenges, new split-system heat pump water heaters are becoming more widely available. These systems separate the tank and compressor, offering more flexibility for homes with limited space, such as mobile and manufactured homes.

Do I need to increase the size of my electrical panel to install an electric space or water heater in my home?

Every home has an electrical panel. Panel capacity refers to the size of the electrical panel, which is measured in amps, and determines how much electricity can safely be used at once. The need to increase your panel size, also called 'panel upsizing,' depends on several factors such as the size of your current panel, your home’s total electricity load, and the type of heater being installed.

Some studies say that panel size can be a problem when trying to install zero-emission space and water heaters.89

Many homes already have 100- to 200-amp panels, which are often sufficient to support all-electric equipment, including space and water heaters and electric cars.1011  However, in some cases, panel upsizing may be necessary. If so, other parts of the home’s electrical system, like the power pole, transformer, or wires, may also need to be updated.

There are several ways to avoid the need for panel upsizing:

  • Low-power heaters: Some heaters operate on lower voltages. For example, a 120-volt heat pump water heater can be plugged into a standard wall outlet instead of needing a 240-volt connection. Similarly, low-voltage heat pump HVAC systems, such as ductless mini split systems, can also work well in homes with limited panel capacity.
  • Panel optimization strategies: A range of tools and devices can help maximize your existing panel capacity without needing to upsize. These include smart circuit breakers, smart panels, circuit pausers, load-sharing devices, sub-panels, meter collars, and smart splitters.
  • Energy efficiency improvements: Reducing your home’s overall energy use through better insulation, energy efficient equipment, and weatherproofing, can help avoid the need for a panel upgrade.

Do heat pump space and water heaters work well in cold temperatures?

Yes! Many modern zero-emission heat pump systems are designed to work well even in cold climates. 

Some zero-emission space heaters work well in temperatures as low as 5 degrees Fahrenheit. These include cold-climate air source heat pumps and geothermal (ground source) heat pumps. In fact, there are over 20,000 cold-climate certified heat pump models available, and the number continues to grow as technology improves. You can visit resources such as the Northeast Energy Efficiency Partnership (NEEP) to see a list of these products.12

For water heating, today’s heat pump water heaters also perform well in cold temperatures. While most models operate best at temperatures above 40 degrees Fahrenheit, many can work below that level. Split-type systems can operate in temperatures as low as –25 degrees Fahrenheit.13  Even 120-volt heat pump water heaters, which heat water more slowly, have been shown to meet hot water needs in a variety of climates.14