What you should know about low GWP refrigerants

Low-Global Warming Potential (Low GWP) refrigerants are being increasingly used in heat pumps and other HVAC refrigerant systems (i.e. appliances, HVAC) to reduce environmental impact and meet new regulations. Meanwhile, preventing leaks in aging equipment is becoming increasingly important.

To understand more about refrigerants, we spoke with Li Ling Young, lead engineering consultant with Efficiency Vermont.

Li Ling: I'm an engineering consultant and I work mostly with residential projects. Efficiency Vermont has a successful leak-reduction program in grocery stores, and now we're taking what we've learned there and bringing it over into what I call "HVAC land." With more homes using heat pumps for heating and cooling, it raises the issue of how to mitigate the harm of refrigerants while gaining the benefits of electrifying our HVAC systems.

Li Ling: In any refrigeration system, including HVAC, the intent is to keep the refrigerant in the pipe. It's supposed to be a sealed system. Refrigerant gets released into the atmosphere through improper installation or an unintentional failure, like some part loosens up over time and doesn't get repaired.

There are many types of refrigerants. Hydrofluorocarbons (HFCs) are one of the most common types. They're thousands of times more harmful to the planet than carbon dioxide, which is the baseline gas that we use to describe global warming potential (GWP). So when we say low-GWP refrigerant, it means the refrigerant is less harmful (relative to other refrigerants) from a climate perspective.

HVAC technicians typically shoulder the burden of making sure heat pumps don't leak. They have their hands on the equipment day in and day out. That means technicians' skills and commitment to quality are paramount. So, my work focuses on improving quality of work and making sure technicians have access to good training and good tools.

Li Ling: They should get it repaired as soon as possible. Any system that needs new refrigerant more than once every three years should be assumed to have a leak. There are other signs that you might have a leak, like if your heat pump is struggling to cool your home, or if there is an oil film at pipe connections.

I encourage people to be good refrigerant stewards. Refrigerant stewardship involves a few things at the beginning, middle, and end of the equipment’s life. At the beginning, it's about being thoughtful about the system you select and installing it properly. In the middle, it's about being diligent about regular maintenance and repairing any leaks. A leaking heat pump or window AC unit is also less efficient, so taking care of leaks quickly will save you money. At the end of life, when you retire the equipment, the refrigerant needs to be recycled by law.

Li Ling: Most waste facilities in Vermont accept appliances that contain refrigerant (refrigerators, freezers, etc.). There’s usually a small fee to drop them off. The transfer station safely removes the refrigerant and then recycles the rest of the appliance as scrap metal. The refrigerant is then sent to an industrial facility where it can be returned to its original purity and reused in other appliances. For air conditioners or heat pump systems, an HVAC technician can remove refrigerant before the equipment is decommissioned.

Li Ling: Yes. There have been many generations of refrigerants since the early days when we discovered the refrigerant cycle. Over time, each generation of refrigerants has been abandoned due to some harmful attributes. Some of them have been human health hazards. Some of them punched a hole in the ozone layer. With the Montreal Protocol in 1987, we've moved away from those refrigerants and toward less harmful alternatives. That effort has been very successful. We had a giant hole in the ozone layer and it's shrinking now. That’s largely thanks to a coordinated effort around the globe.

Now we're transitioning to a new class of lower-GWP refrigerants. This year a new type of refrigerant will go into residential HVAC systems. It's a legally mandated process to reduce the harm of these chemicals. The new refrigerant will be about a third as potent as the residential refrigerant that has been in use for the last 25 years.

Even though we're on this trajectory of using less harmful refrigerants, we still have lots of systems out there with older refrigerants in them. If over time we're just like, "whoops, we lost a little bit here and there," we will have accomplished literally nothing (from a climate perspective) by switching to the new refrigerants. My hope is that by working with HVAC technicians to refine best practices for refrigerant management, we’ll keep more refrigerant in the pipe, and see more refrigerant recovered at the end of equipment life. Over time there will be less of the higher GWP refrigerants in circulation.

Li Ling:  The most important thing is that new equipment will have to be manufactured with the lower-GWP refrigerant. Heat pumps manufactured in 2024 with the old refrigerant can still be sold through 2025. If you're in the market for a new HVAC system and climate change is your top priority, you might consider the new heat pumps during this transition year. But it only makes sense to replace your existing heat pump if it’s leaky and can’t be repaired. The best thing to do for the climate is to keep using and maintaining your current heat pump until the end of its usable life.

Li Ling: If you need a new appliance because your old one is broken, you can shop for a low-GWP version. But it doesn’t make climate sense to replace a functioning appliance. Currently, Efficiency Vermont offers rebates for ENERGY STAR dehumidifiers and low-GWP window air conditioner models.

Li Ling: Appliances and heating systems that use refrigerant are supposed to be closed systems. So, while the planet-harming impacts of rogue refrigerants are important to consider, heat pumps are still a big improvement over heating systems that burn fossil fuels. I think we'll see near-zero GWP refrigerants in the future. But we can’t afford to wait, and that’s why we’re on a slower journey that takes us through these with progressively lower-GWP refrigerants. We just need to be good stewards of our equipment, which translates to being good stewards of the planet.