Global Warming Potential Definition
Global Warming Potential (GWP) is a metric used to quantify how much heat a greenhouse gas (GHG) traps in the atmosphere over a set period, which depends on the type of gas. The higher a gas’s GWP, the greater its contribution to global warming.
GWP allows stakeholders to compare the climate impact of various gases, including those used as refrigerants in HVAC systems.
Why GWP Matters in HVAC
Refrigerants are essential for heat transfer in air conditioning and heat pump systems, but many of them are greenhouse gases. When released into the atmosphere, these substances can significantly contribute to climate change.
While some GHGs occur naturally and support life (like water vapor), others, like chlorofluorocarbons (CFCs) and hydrofluorocarbons (HFCs), are human-made and persist in the atmosphere, trapping heat and contributing to global temperature increases. As a result, regulations around refrigerants are evolving globally, with industry and governments working to reduce the environmental impact of these substances.
How GWP Is Calculated
GWP compares the global warming effect of a gas to that of carbon dioxide (CO₂), which has a baseline GWP of 1. For example, a refrigerant with a GWP of 200 traps 200 times more heat per unit than CO₂ over the same period.
The Intergovernmental Panel on Climate Change (IPCC) and the U.S. Environmental Protection Agency (EPA) use a standardized 100-year GWP value from the IPCC’s Fourth Assessment Report (AR4) in regulatory frameworks.
R-410A Phase-Down and the Shift to Low-GWP Refrigerants
CFC refrigerants have the highest ozone depletion levels, very high GWP, and have already been phased out. HCFC refrigerants, such as R-22 (HCFC-22) or Freon™, have also been phased out in new equipment by the Environmental Protection Agency (EPA) because of their ozone depletion potential (ODP).
R-410A refrigerant is a blend of hydrofluorocarbon (HFC) refrigerants R-32 and R-125 that replaced R-22. However, the global warming potential of R-410A is 2088. To comply with the American Innovation and Manufacturing (AIM) Act of 2021, the EPA has set a 700 GWP limit for HVAC systems starting in 2025. In response, Trane and other manufacturers are transitioning to low-GWP refrigerants that meet or exceed performance expectations while reducing environmental impact.
Two of the most promising refrigerants for commercial and residential applications include
- R-32 – GWP of 675 (68% lower than R-410A)
- R-454B – GWP of 466 (78% lower than R-410A), with improved efficiency and zero ozone depletion potential
Beyond Refrigerants: Energy Efficiency Amplifies Impact
While refrigerant choice matters, another climate benefit comes from the increased energy efficiency of new HVAC systems. New HVAC systems that use lower GWP refrigerant are also typically more energy efficient than older systems.
This dual benefit — low-GWP refrigerants plus higher efficiency — offers an actionable path for organizations aiming to decarbonize operations and meet internal or external sustainability goals.
Trane’s Sustainability Commitment
Trane’s transition to low-GWP refrigerants aligns with our broader environmental mission: the Gigaton Challenge. Our goal is to help reduce one billion metric tons of carbon emissions from our customers’ operations by 2030, which is the equivalent of the combined annual emissions of Italy, France, and the U.K.
We’re supporting this transformation by
- Redesigning our HVAC systems for next-gen refrigerants
- Providing education and technical guidance to the engineering and contracting community.
- Ensuring continuity of service for legacy equipment during the transition
Looking Forward
If you operate or manage a building with HVAC systems that use R-410A or R-22, now is the time to begin planning your refrigerant transition. Trane offers support in system design, retrofitting, and incentive navigation to ensure a smooth switch to more sustainable technology.
Talk to a Trane Commercial expert to explore solutions that help you meet regulatory requirements while advancing your sustainability goals.
