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Clean energy journalism for a cooler tomorrow

California could ban new gas heaters after 2030. The goal: Healthier air

Ditching fossil-gas furnaces and water heaters isn’t just good for the climate. Research shows it’s a smart move for human health.
By Jeff St. John

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The flame of a gas boiler pilot light

[Update: the California Air Resources Board approved the plan to ban gas-fueled furnaces and water heaters shortly after this story was published]

Government agencies and clean-energy advocates have a new tool they can use to push for switching buildings from fossil fuels to electricity: the emerging scientific consensus on the health harms that come from burning fossil gas indoors.

Later this month, the California Air Resources Board is expected to vote on proposed air-quality standards that would bar the sale of gas-fueled furnaces and water heaters in the state after 2030. If approved, it would be the first zero-emissions target for building heating systems from a state air regulator in the U.S.

This new ban would join a range of California policies encouraging the shift from gas to electric heating and appliances, from last year’s passage of electric-friendly building codes to this month’s decision ending utility subsidies for extending gas pipelines to new buildings. It would also dovetail with the various types of gas bans passed by more than 60 city and county governments across the state.

Indoor fossil fuel use accounts for roughly 12 percent of total U.S. carbon emissions, making it an important target for efforts to combat climate change. But CARB’s proposal, which is part of a much broader plan to move the state toward compliance with federal Clean Air Act standards, isn’t primarily justified by the goal of reducing carbon emissions. Instead, it’s intended to reduce the nitrogen oxide (NOx) emissions that contribute to smog-forming and health-harming ozone and particulate air pollution.

A growing body of scientific evidence shows that emissions from burning gas to heat buildings, cook food and dry clothes are a far more significant source of NOx emissions than previously realized. Beyond being a precursor to the formation of smog, NOx can be a significant cause and exacerbator of asthma, heart disease and other health problems on its own.

More than half of all Californians live in areas with unsafe levels of ozone pollution,” as do 99 percent of all disadvantaged communities in the state, said Denise Grab, a principal on the Carbon-Free Building team of nonprofit decarbonization think tank RMI. (Canary Media is an independent affiliate of RMI.) This map shows how much of California remains in nonattainment” status for ozone pollution under U.S. Environmental Protection Agency regulations, which means they exceed the limits set forth in one or more of the National Ambient Air Quality Standards.

Map of California with areas of high ozone pollution indicated
Much of California suffers from ozone pollution that exceeds federal air-quality standards, as this map indicates. (CARB)

This pollution accumulates inside buildings as well as affecting outdoor air quality. Both have serious health implications, according to a report released today from RMI, the Sierra Club and the San Francisco Bay Area Planning and Urban Research Association. Building on data and methods used in a study released last year from the Harvard T.H. Chan School of Public Health, RMI found that indoor fossil fuel use is responsible for 470 deaths and more than $5 billion in health impact costs per year in California.

For decades, regulators have targeted cars, trucks, power plants and industrial sites to reduce air pollution. But in California, gas appliances emit four times more emissions than all of the state’s power plants put together, and nearly two-thirds of the emissions of all light-duty cars,” Grab said.

Nearly 90 percent of these in-building gas-burning NOx emissions are from space and water heating, making these a priority target for air quality regulations. That’s true well beyond California’s borders, Grab noted. This map from a 2021 RMI report highlights where higher levels of NOx emissions from building appliances overlap with areas designated by the EPA as being out of compliance with Clean Air Act standards across the country.

Map of country's ozone nonattainment zones overlaid with NOx emissions from indoor burning of fossil fuels
High levels of NOx emissions from fossil-fueled indoor heating and appliances overlay many parts of the country with high levels of ozone air pollution. (RMI)

Last month, a coalition of 25 environmental and public health groups filed a petition calling for the EPA to take a nationwide approach to regulating indoor air pollution. The petition asks the EPA to regulate fossil-fueled indoor appliances much as it regulates power plants and oil refineries, starting with a NOx performance standard for furnaces and water heaters that the groups hope will lead to a zero-emissions standard by decade’s end.

While state and regional regulations can play an important role, this really is a national problem,” said Amneh Minkara, deputy director of the Sierra Club’s building electrification campaign. This is a massive public-health threat that for decades has gone unregulated.”

Opposition from the gas industry, support from appliance makers

Fossil gas industry groups and gas utilities have been fighting efforts to regulate or restrict gas-fired heating and appliances. Since cities and counties in California and beyond have started imposing bans on fossil gas use in new buildings, the gas industry has lobbied for state laws that would prohibit such local action. More than 20 states with Republican-controlled legislatures have now passed these preemption” laws. California’s city and county gas bans have come under attack by groups funded by Southern California Gas, the state’s largest gas utility.

As for the health impacts of gas-burning appliances, the American Gas Association trade group has pointed to the lack of federal regulations as a reason to cast doubt on the data and methodology of studies like those cited by RMI and the Sierra Club, based on the dubious logic that if the federal government hasn’t been spurred to take action, there’s no reason for states to. Ted Williams, AGA’s director of codes, standards and technical support, told NPR last year that climate groups are first and foremost interested in electrification for climate concerns” and have glommed onto indoor air quality as being a soft spot in the issue of direct use of natural gas.”

Climate and environmental groups say that regulating indoor gas use to limit health harms isn’t in conflict with seeking to reduce its climate-change impacts. 

What is important, Grab said, is that policies to replace fossil-fueled heating and appliances with electric-powered systems such as heat pumps and induction ranges support the lower-income and disadvantaged communities that have borne the brunt of both climate change and local air pollution.

Communities of color have disproportionately suffered the harms of emissions from oil and gas wells, oil refineries, industrial sites, ports and trucking corridors. A recent study of Bay Area air quality found that communities of color are exposed to 55 percent more NOx than mostly white communities.

Lower-income communities also tend to live, work and learn in buildings with poorly maintained heating and ventilation systems, increasing the health risks of burning gas for heat. Replacing older gas-fired heaters with electric heat pumps in these communities could deliver climate, health and economic benefits alike.

Air regulators in California’s San Francisco Bay Area and Los Angeles Basin areas project significant health improvements from the zero-emissions heating regulations they’re developing, which could expand on CARB’s statewide regulations. Heat pumps can both heat and cool more efficiently than air conditioners or gas-fired or electric resistance heaters alone, lowering energy bills in the long run. And incentivizing heat pumps in the roughly 3.4 million California homes that lack central air conditioning could provide cost-efficient cooling during the state’s increasingly dangerous heat waves, according to the report from RMI, the Sierra Club and the San Francisco Bay Area Planning and Urban Research Association.

It’s really important that low-income communities have equal, if not first, access to these technologies,” RMI’s Grab said. That will require policies to reduce their higher upfront cost, make them accessible to renters, limit the risk of rising electricity rates eroding their long-term economic value, and build up a workforce to install and maintain them, she said.

These issues aren’t just a concern of groups like RMI and Sierra Club. Major HVAC and water heater vendors including Carrier, Daikin, Fujitsu, Johnson Controls, Mitsubishi Electric, Rheem and Trane joined dozens of environmental justice groups in signing an August letter supporting CARB’s proposed 2030 zero-emissions standards for heating equipment — on the condition that the state makes these equity and workforce-development policies a priority.

It’s very equity-focused,” said Panama Bartholomy, executive director of the Building Decarbonization Coalition, one of the letter’s signatories. I don’t know of any other documents that large corporations like Carrier and Johnson Controls and Rheem have signed onto that take that much of a social justice direction.”

To be clear, these HVAC and water heating companies stand to benefit from the new markets such regulations could spur. More than 90 percent of California’s 14.4 million households rely on gas for space or water heating, posing a massive retrofit challenge. The $54 billion climate package passed by the California legislature last month includes $1.1 billion in building-decarbonization funding, as well as a goal of deploying 6 million heat pumps in buildings by 2030.

Sierra Club’s Minkara highlighted the intense and multi-level transition that has to happen” to hit targets like these in California, let alone achieve building electrification across the country.

But according to Minkara, the timing has never been better” to take on this challenge. The Inflation Reduction Act passed by the U.S. Congress last month contains tens of billions of dollars in tax rebates, grants and lending authority to support energy efficiency and electrification, along with billions of dollars to support environmental justice initiatives that could bolster deployment in disadvantaged communities.

Combining these incentives with zero-emissions standards like the ones being considered by the California Air Resources Board could help align equipment manufacturers, contractors and installers behind this electrification push, she said. Backers of the petition to the EPA are hoping this momentum builds into a push for a national standard.

California’s move could show the way. In the interim, the goal is to send a strong market signal to say, This is a viable policy, and it will help achieve the commitments we’ve made on public health and on climate policy,’” Minkara said. But to address the nationwide market for furnaces and water heaters — and the nationwide need to regulate their health impacts — a federal approach is the ultimate goal. It would be better to have one harmonious standard rather than this patchwork,” she said. 

Jeff St. John is director of news and special projects at Canary Media. He covers innovative grid technologies, rooftop solar and batteries, clean hydrogen, EV charging and more.