A secretive vote in the arcane and Byzantine world of international safety standards late last month may lead to a dramatic reduction in greenhouse gas emissions from home heating and cooling systems in the coming years.

In a closed-door process that concluded on April 29, two dozen technical experts from around the world voted unanimously to approve a proposed update to a household appliance safety standard set by the Geneva, Switzerland-based International Electrotechnical Commission (IEC).

The IEC sets safety standards for thousands of household appliances. The international standard serves as a guideline for country-specific safety standards such as UL, formerly Underwriters Laboratories, safety standard in the U.S. Details about the subcommittees that shape the safety standards are typically kept confidential. IEC declined to provide additional information about the vote, including the names of individual country representatives who approved the update. 

The update, a draft copy of which IEC shared with Inside Climate News and which IEC plans to publish next month, could help solve a significant climate problem that has long bedeviled manufacturers of air conditioners and high efficiency electric heating systems known as heat pumps, which wanted to use more climate-friendly refrigerants but were prevented from doing so.  

The vast majority of air conditioners and heat pumps used around the world today rely on hydrofluorocarbons (HFCs), synthetic chemical refrigerants that, when leaked into the atmosphere, are highly potent greenhouse gases. The approved safety standard update will allow appliance manufacturers to instead use hydrocarbon refrigerants that have a negligible climate impact.

The Environmental Investigation Agency, an environmental organization based in Washington that has advocated for the use of hydrocarbon refrigerants for decades and was one of the first to publicly announce the results of IEC’s vote, says the change could save the equivalent of billions of metric tons of carbon dioxide emissions by 2050.

“This is a crucial milestone because this sector, the air conditioning sector, needs to transition away from HFCs if we are to even keep the hope alive of staying within a 1.5 degree Celsius warming world,” said Avipsa Mahapatra, EIA’s climate campaign lead.

Most air conditioners and heat pumps in the United States today rely on HFC-410a, a chemical refrigerant that is 4,260 times as potent as carbon dioxide at warming the atmosphere over a 20-year period. 

The use of such powerful greenhouse gases in household appliances is problematic because the chemical refrigerants slowly leak out of the devices and into the atmosphere. At the end of an appliance’s useful life, the remaining refrigerant typically enters the atmosphere when the device is crushed for scrap metal unless careful measures are taken to collect and destroy the refrigerant.

Over its lifetime, a heat pump that relies on HFC 410a will release 12 pounds of the refrigerant into the atmosphere. The climate impact of such a release, measured over a 20-year period, is equivalent to the greenhouse gas emissions of burning 54 barrels of oil or driving a car for five years, based on the EPA’s Greenhouse Gas Equivalency Calculator which assumes an average distance of vehicle miles traveled of 11,520 miles per year.

The high efficiency of heat pumps relative to other methods of heating buildings means that, from a climate perspective, they are still the most climate friendly method of home heating in most circumstances. However, if their refrigerant emissions could be reduced, the climate benefit of using the devices would improve significantly.  

A Key First Step, Though Change in the US Could Take Years

Regulations set by the state of California require air conditioning manufacturers to phase out HFCs that are most harmful to the climate, including HFC-410a, by 2025, and federal regulators are considering a similar rule.

The federal rulemaking is part of the AIM Act, which was approved with bipartisan and industry support in legislation signed into law in December 2020 by then-President Donald Trump. The AIM Act complies with an international agreement known as the Kigali Amendment to the Montreal Protocol to phase down the production and use of HFCs. If left unchecked, HFC emissions were expected to fuel an additional half a degree Celsius of warming by 2100.  

Many appliance manufacturers are now switching to HFC-32, a refrigerant that is less potent as a greenhouse gas. However, HFC-32 is still 2,430 times worse for the climate than carbon dioxide over a 20-year period.

The newly passed update by the International Electrotechnical Commission will allow significantly higher limits on the amount of “A3,” or “flammable” refrigerants, including hydrocarbons such as propane, that can be used in heat pumps and air conditioners. The update effectively allows the use of such refrigerants for the first time.

Propane and other hydrocarbon refrigerants have been safely used in refrigerators in Europe and elsewhere for decades and, in recent years, that use has extended to the U.S. The use of propane in air conditioners, however, has been blocked by safety standards that appliance manufacturers and environmental advocates say are overly restrictive and designed to protect the interests of U.S. chemical manufacturers.

Hydrocarbon refrigerants, or what proponents call “natural refrigerants,” are only about three times as powerful as carbon dioxide as greenhouse gases. The small volumes of the refrigerants that are used in household appliances not only help ensure their safety but would make any release of these significantly less potent greenhouse gases largely negligible.

The update to the international safety standard, which had been under discussion and revision for nearly seven years before the recent vote, is widely seen as a key first step for the expanded use of more climate-friendly refrigerants.  However, U.S. safety standards and local building codes would have to adopt the new international standard before U.S. retailers can sell air conditioners and heat pumps that use propane or other hydrocarbon refrigerants. That process could take years.  

U.S. regulations and building codes follow national safety standards set by UL and the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE).

Steven Brewster, a UL spokesman, confirmed that the U.S. representative who was part of the vote on the updated international standard voted in favor of the update allowing for the expanded use of hydrocarbon refrigerants. Brewster said that U.S. and Canadian safety standard experts would review the update to the international safety standard once it is officially published.  UL often adopts safety standards set by the IEC but is not required to. 

ASHRAE declined to comment.

A recently launched U.S. heat pump manufacturing company that promises “planet-friendly heating and cooling” welcomed the news.

“We’re currently caught in this vicious cycle where the more air conditioning and heating we use, the warmer the climate gets and the more we need air conditioning,” Vince Romanin, CEO of heat pump manufacturer Gradient, said.  “The refrigerants we use today are not sustainable and scalable to a world where everyone has access to comfortable buildings that don’t make warming worse.”

When Romanin started his company five years ago, he sought to use propane refrigerant because of its low climate impact. However, he has been stymied by U.S. safety standards.

“We’re really excited about what IEC has done and we’re looking forward to the U.S. pushing change through faster to get similar rules for natural refrigerants,” he said.