“The carbon dioxide used as a refrigerant is generally of industrial or scientific grade and is typically recovered from the waste streams of industrial processes.”

ASHRAE, Refrigerants and their Responsible Use

CO2 (R-744) is a refrigerant option that, with the right investment in energy efficiency improvements, can be a workable solution for certain applications. CO2 has a A1 safety classification (“lower toxicity, no flame propagation”). CO2 performs best in cooler climates where ambient temperatures do not impact its energy efficiency.

Carbon dioxide is manufactured to meet refrigerant quality specifications via industrial gas processing and purification technology.

R-744 has unique safety and operational properties that require service technicians obtain specialized training and purchase dedicated tools.

Switching to CO2 in existing systems is not possible without more complex, large-scale renovations and new equipment. The greater complexity can drive cost and require more downtime for retailers and other end-users. For this reason, these systems are typically only developed as part of new builds.