LEBANON — Manufacturers of heat pumps, an increasingly popular option for New England homeowners seeking an eco-friendly alternative to fossil-fuel heating, will be searching for alternatives of their own with new federal rules limiting a widely used class of refrigerants.
Last month the Environmental Protection Agency issued new rules to limit hydrofluorocarbons, potent greenhouse gases that flow through most heat pumps, following legislation passed in Congress last year calling for their phaseout. The HVAC industry is looking for ways to replace these pollutants with more environmentally friendly alternatives.
“The regulations are ahead (of the technology), but they give the industry 10 years to start doing it,” said Kim Quirk, who works with ReVision Energy, an Enfield-based solar company that often incorporates heat pumps into its installations.
Unlike furnaces, which burn fuel to generate heat, heat pumps trap heat from outside and transfer it into a building, using flowing refrigerants and coils to capture and transfer heat in much the same way an air conditioner does, but in reverse. About six years ago, the HVAC industry developed technology capable of capturing heat in frigid winter air, making them much more practical in cold regions like northern New England.
Since then, Quirk said, heat pumps’ popularity “increased dramatically due to both the cost savings and the low emissions.”
Heat pumps have a significantly smaller carbon footprint than boilers or furnaces, not least because they are powered by electricity, which can come from renewable energy sources, Quirk said. However, they typically rely on hydrofluorocarbons, whose “global warming potential” — a number that measures the relative impact of different gases on global warming — can be hundreds to thousands of times higher than carbon dioxide, according to the EPA.
ReVision Energy installs Mitsubishi heat pumps that operate using a hydrofluorocarbon refrigerant with 2,088 times the warming impact of carbon dioxide, according to the manufacturer.
While a boiler or furnace burns and emits fossil fuels by design, heat pumps usually emit refrigerants only through leaks, she said.
“Refrigerants in a heat pump are never meant to leave the pipes. They’re not supposed to go into the air. They’re stuck in the pipes and they go around and around,” Quirk said. “It’s so much better to do that than to burn any kind of fossil fuel, even wood in my opinion, than let the emissions go into the air.”
Still, heat pumps do leak, especially when they are first installed or disposed of at the end of their life cycle, Quirk said. The EPA has used its certification program to ensure that licensed technicians know how to limit leaks when heat pumps are manufactured, installed and recycled.
The EPA’s new rules are not the first time of regulations have pushed the HVAC industry to find more environmentally friendly refrigerants. Early air conditioners and refrigerators used toxic, highly flammable natural refrigerants such as propane. Then, safer artificial chemical compounds were developed, but scientists found that they contributed to the depletion of the ozone so regulations pushed the industry to replace these “ozone-depleting substances.” These regulations did indeed benefit the ozone, but they also contributed to the increasing use of hydrofluorocarbons.
Global reporting standards mandate that companies reporting their emissions take refrigerants into account, which Hypertherm, the Lebanon-based manufacturer of cutting technology, began to do in 2019. In 2020, its facilities emitted refrigerants equivalent to 452 tons of carbon dioxide. Heating fuel used by Hypertherm across its facilities, meanwhile, accounted for the equivalent of 943 tons of carbon dioxide.
“The industry has already retired refrigerants with the highest global warming potential and has developed new ones with much lower global warming potential,” said Robin H. Tindall, who leads Hypertherm’s environmental stewardship team. Some hydrofluorocarbon refrigerants have a much higher impact on the atmosphere than others. Tindall said that about 95% of an HVAC system’s total global warming potential comes from electricity used, while only 5% comes from the refrigerants.
The short-term potency of hydrofluorocarbons means that a targeted attempt to limit their emissions has the potential to make a real dent in limiting climate change: A global limit on the super-pollutants may limit as much as 0.9 degrees Fahrenheit of global warming, according to the EPA.
On the state level, Efficiency Vermont is targeting refrigerants. Tori Scarzello, who manages programs for small businesses, said that the energy efficiency utility has been working with businesses to limit leaks.
In 2019, Efficiency Vermont estimated that “if all Vermont’s commercial refrigeration systems cut their annual leakage rate in half, it would save 97,000 metric tons of carbon equivalent annually” — or the annual emissions of over 21,000 passenger cars.
All refrigeration systems leak with age and use. Leaks are not only sources of greenhouse gases entering the atmosphere, but also raise electricity bills. Efficiency Vermont offers a rebate that covers 80% of the cost, up to $3,000, of detecting and repairing a leak.
Efficiency Vermont’s incentives are in step with recent state-level legislation. The Vermont Agency of Natural Resources adopted a new rule in 2020 that pushes the state to limit emissions from hydrofluorocarbons. As of January 2021, the agency prohibited hydrofluorocarbons in new commercial and residential refrigerators, as well as foam insulation. New Hampshire has not passed any legislation targeting hydrofluorocarbons. However, NHSaves, a collaboration among the state’s utilities companies, does incentivize home and business owners to install efficient refrigerators and recycle old equipment responsibly.
Efficiency Vermont is also working to replace refrigerators that use hydrofluorocarbons with ones that use “natural refrigerants.”
Some of the natural refrigerants used in emerging technology, like carbon dioxide, are not as flammable as the natural refrigerants of the past. New, high-efficiency equipment allows natural refrigerants to completely replace hydrofluorocarbons, delivering both savings and lower emissions, according to Efficiency Vermont. However, making the switch to natural refrigerants requires businesses or homeowners to completely replace their equipment, a cost that the utility can help finance.
For now, consumers are weighing various options and working with what is available.
Sloane Mayor, a Hanover architect, recently retrofitted her home with a focus on sustainability and energy efficiency. She installed Mitsubishi heat pumps that run on hydrofluorocarbons.
“I think it’s a question of balance,” she said. “The technology that heat pumps use is much more efficient than other technologies like boilers or furnaces, so there’s an offset.”
Claire Potter is a Report for America corps member. She can be reached at cpotter@vnews.com or 603-727-3242.