This annex aims at promoting low-GWP refrigerant application to accelerate phase-down of high-GWP HFCs by developing design guidelines of optimized heat pump components and systems for low-GWP refrigerants through the review of available low-GWP refrigerants, their properties and applicable standards, safety, and flammability of refrigerants, and safe use of flammable refrigerants; optimization of heat pump components and system for low-GWP refrigerants; analysis of the LCCP impact by the current design and optimized design with low-GWP refrigerants; and market opportunity study for heat pumps with low-GWP refrigerants and low-GWP refrigerants availability for 2030. Target applications are air-conditioning and heat pump systems for residential and commercial buildings.


In 2016, 197 countries adopted an amendment to phase down HFCs under the Montreal Protocol in Kigali, Rwanda. Under the amendment, countries committed to cut the production and consumption of HFCs by more than 80 percent over the next 30 years. The goal is to avoid more than 80 billion tons of CO2 eq emissions by 2050 and avoid up to 0.5°C warming by 2100. The refrigerant used in refrigeration and air conditioning systems is responsible for about 2% of global greenhouse gas emissions. In 2000, stationary air conditioning systems account for 37% of global refrigerant emissions and 21% of CO2 equivalent emissions of refrigerants. However, more than 80% market growth of air conditioning systems is projected especially in developing countries due to their economic growth and climate changes.

Future heat pump systems will use low-GWP refrigerants and energy-efficient technologies to meet the latest international regulations and reduce overall environmental impacts. Low-GWP refrigerants candidates are R-32, R-32 mixtures, and natural refrigerants (HCs and CO2) and their GWP values will be lower than 700.  Since candidate refrigerants have a wide range of thermophysical properties and thermodynamic characteristics, which are different from current refrigerants, customized and optimized components, and system designs for new low-GWP refrigerants are very important.  The proposed Annex will explore this new opportunity and contribute to expanding the optimized low-GWP air conditioning and heat pump systems, advancing their technology readiness levels (TRL) by developing design guidelines for low-GWP technologies, assisting to reduce their market barriers, and promoting international collaboration.  Therefore, the proposed annex aligns with IEA’s vision and mission by targeting clean, low-carbon energy systems’ design and applications. This annex will assist IEA to achieve its strategic goals by promoting new, alternative, or natural refrigerants with lower GWP for heat pumps.

Contact Person

Mr Yunho Hwang, yhhwang@umd.edu

Participating Countries

Austria, France, Germany, Italy, Japan, South Korea, Sweden, the USA


Field News

IEA Annex 54 Annual Report 2021

The Annual Report 2021 for Annex 54 – Heat Pump Systems with Low-GWP Refrigerants, is now available. This report provides...