A. O. Smith Releases New CO₂ Hot Water Heat Pump Water Heater for the U.S. Market

American manufacturer A. O. Smith has released a new CO₂ (R744) split heat pump water heater (HPWH) for the U.S. market designed for use in cold climates.

Dubbed Voltex X, the new unit has a heating capacity of 4.5kW (1.2TR) and was designed in partnership with Panasonic, which manufactures commercial and residential propane (R290) heat pumps and recently released a residential CO₂ heat pump water heater in Australia. This is “the first widely available outdoor split system heat pump water heater” in the U.S., according to A. O. Smith, and is reportedly the second residential HPWH on the U.S. market to use CO₂ refrigerant. The manufacturer said the Voltex X can reduce utility costs by 76% compared to standard electric water heaters.

Designed to fit in: The unit can be installed in locations where ambient temperatures fall as low as −25°F (−4°C) and go as high as 109°F (43°C).

• There are three storage tanks available, 50, 66, and 80gal (189, 250 and 303L), with the 50gal tank available in three designs so it can fit in space-constrained spaces.
• The outdoor unit runs a water line to the indoor unit, with hot water circulated through the lines to prevent freezing.

Future plans: A.O. Smith said the Voltex X is available across the U.S.

• The company is set to launch a bigger 6kW (1.7TR) model. Up to 30 of these can be connected together for commercial installations.

A market warming up: The U.S. market for CO₂ heat pump water heaters is slowly starting to develop. 

• In January 2026, Noritz Corporation and Nihon Itomic Co. announced they will develop a commercial R744 HPWH for the North American market.
• In February 2024, U.S. commercial water heater manufacturer Intellihot started installing CO₂ tankless heat pump water heaters. Intellihot was acquired by Zurn Elkay Water Solutions in July 2026.

Quotable: “The Voltex X unit furthers accessibility to critically important heat pump technology in areas where it has not always been feasible to install a heat pump water heater,” said Brad Vossler, Senior Product Manager at A. O. Smith, in a statement. “Being limited by environmental conditions, such as temperature and space constraints, is now a thing of the past.”