Philip Johnston

Low GWP Program Leader, Daikin Applied

Licensed Professional Engineer, Ontario

The Earth isn’t cooling. Carbon dioxide levels in the atmosphere have been rising steadily since the Industrial Age, contributing to global warming and putting the planet at risk. Independent research shows the role that HVAC plays in this equation: stationary air conditioning contributes up to 20 percent of electrical consumption in buildings today and the use of air conditioning is projected to triple by 2050.1 If we continue developing the world as is, without controls, temperatures are forecasted to rise up to 0.6 degrees Celsius directly from hydrofluorocarbon (HFC) emissions.2 The good news, though, is that research shows that making the right refrigerant choices has the potential to limit the temperature rise due to HFC emissions to 0.06 degrees. That’s six one-hundredths of a degree. And that’s why the HVAC industry is striving for HFC phasedowns, improved efficiency and beneficial decarbonization.

With this data in mind, it’s becoming more important than ever to achieve improved energy efficiencies. Previous policies, such as the Montreal Protocol, were designed to improve HVAC climate performance. The Protocol was adopted globally in 1989 to protect the ozone layer by eliminating the use of ozone depleting substances over time. High ozone depletion potential (ODP) chlorofluorocarbons (CFCs) were phased out in 1996, followed by lower ODP refrigerants, which are still transitioning out. In October 2016, more than 170 countries agreed to amend the Protocol. The Kigali Amendment was created to phase down HFCs by reducing their production and use. Today’s common refrigerants like R-134a and R-410A are targeted in this phasedown.

The net: It’s time for the HVAC industry to transition to next-generation refrigerants. And R-32 has risen to the top of potential options.

Based on independent research and testing conducted by HVAC supplier Daikin, there are numerous benefits offered by using R-32 refrigerant, including efficiency, reduced usage and cost-effectiveness.

Efficiency: According to Life-cycle Climate Performance (LCCP) studies^3,4,5,6,7, electricity consumption can contribute up to 85 percent of total carbon dioxide emissions over an HVAC system’s lifetime. As a result, a refrigerant that achieves higher energy efficiency in use could be more effective in protecting the climate than its global-warming-potential (GWP) rating suggests. The total electricity consumption of an air conditioner or heat pump depends on a number of factors, including the regional climate, building load and energy efficiency. Since the location and load are the same for a given application, the differentiating factor between systems is typically system efficiency. Daikin’s analysis of inverter-driven compressor performance in rooftop units and water-cooled chillers found that full-load and partial-load efficiency rating metrics can be improved by up to 12 percent using R-32 instead of R-410A. More efficient systems consume less electricity. As a result, a small change in efficiency can make a significant reduction in environmental impact over the system’s lifetime.

Reduced usage: Because of R-32’s excellent thermodynamic performance characteristics, an R-32 system could have up to 40 percent less charge than R-410A in certain applications, leading to reduced refrigerant usage, as well as the potential for less environmental leakage.  

Being a pure, single-component refrigerant, R-32 can’t lose its composition like a blended refrigerant and is well suited to retain its quality over time. R-32 can be topped off and recharged in the field in both liquid and gas phases. The composition doesn’t change, so it’s easy to clean and reuse on site. R-32 can be reclaimed and recycled with a simple cleaning process, as compared to blends that must typically be distilled to their pure compounds and then remixed. R-32’s properties can help HVAC engineers design systems that have a lower greenhouse-gas-emissions impact than R-410A. R-32 has greater latent heat capacity than R-410A, which means that R-32 systems could be designed to achieve the same capacity performance by circulating less refrigerant at a lower flow rate through the compressor. And a lower charge of R-32 refrigerant in comparison to R-410A allows HVAC engineers the opportunity to design smaller compressors, piping, and coils. These characteristics of R-32 help give engineers the tools they need to design R-32 systems, offering energy savings and a reduction in the material used. And these indirect benefits can have a significant impact on the environment that are not accounted for in a GWP rating alone.

Cost-effectiveness:  R-32’s cost effectiveness comes from several sources. Lower charge means service technicians and building operators have to buy less refrigerant; plus, R-32 historically has a lower price per pound than R-410A and a much lower price per pound than most available proprietary low-GWP blends. With no active patents on the basic molecule, R-32 is manufactured and distributed globally, making it a widely available and accessible commodity. In fact, refrigerant manufacturers have already produce more than 200,000 tons of pure R-32 (partially because it makes up half of the R-410A blend). R-32 has also been selected as the alternative to R-410A by more than 40 manufacturers in geographies spanning Asia, Europe, India and North America. Today it's safely deployed in over 100 million units including residential splits, variable-refrigerant-flow units, scroll chillers, rooftop systems and window units. R-32 has become the de facto global standard to replace R-410A in many HVAC applications.

For these reasons and more, single component R-32 is the most balanced and ideal refrigerant to replace R-410A for many residential, light commercial and applied applications. While the refrigerant’s lower GWP is an important component, an informed choice requires a holistic evaluation of the environmental impact, cost effectiveness, availability, recyclability, energy efficiency, safety and ease of handling. Technology with R-32 refrigerant is proven to outperform the current generation of R-410A products, while also providing a better value for the building owner and a better outlook for the planet.

1. International Energy Agency, “The Future of Cooling: Opportunities for Energy Efficient Air Conditioning,” 2018.  

2. National Oceanic and Atmospheric Administration, “Scientific Assessment of Ozone Depletion,” 2018.

3. Zhang M., et al. 2011. “Life Cycle Climate Performance Model for Residential Heat Pump Systems.” AHRTI Report 09003-01

4. Troch S., et al. 2016. “Life Cycle Climate Performance Evaluation.” International Institute of Refrigeration 

5. Anderson S., et al. 2018. “Life-Cycle Climate Performance Metrics and Room AC Carbon Footprint.” 

ASHRAE Technical Feature

6. Optimized Thermal Systems. 2016. “An Evaluation of R32 for the US HVAC&R Market.” 

7. Zhang M., et al. 2012. “Life Cycle Climate Performance Model for Residential Heat Pump Systems.” International Refrigeration and Air Conditioning Conference. Paper 1311. (http://docs.lib.purdue.edu/iracc/1311)