Next Up in Heat-Pump Refrigerants: Carbon Dioxide

Over the past 25 years, refrigerants used in air conditioners and heat pumps have come under fire—first for their impact on the Earth’s protective ozone layer and then for their global warming potential. Now, some manufacturers are looking to carbon dioxide as the refrigerant.

The Japanese company Mayekawa, one of the first out of the gate with CO2 technology, offers three such heat pumps in North America for commercial applications. With the potential to produce high-temperature water in both water-to-water and air-to-water heat pumps, such systems have become a viable replacement for fossil-fuel-fired boilers in some applications—an area until now untouched by heat pumps.