Mitsubishi Electric Trane HVAC US (METUS) has released Heat2O, an all-electric domestic hot-water heating system designed to improve sustainability and reduce energy consumption in multifamily buildings and large-scale commercial facilities. The Heat2O heat pump water heater (QAHV-N136TAU-HPB(-BS)) reduces the environmental impact of domestic hot water through energy-efficient operation while using CO2, a natural and environmentally friendly refrigerant with a global-warming potential of one and an ozone-depletion potential of zero. Able to produce high-volume domestic hot water without fossil fuels, Heat2O c help large-scale facilities qualify for sustainability certifications or achieve zero-energy and Passive House status. Components include hot-water storage tanks, swing tanks, secondary heat exchangers and variable-speed secondary circuit pumps. Heat2O transfers ambient thermal energy from outdoor air to potable water by cycling refrigerant. Natural CO2 refrigerant enables Heat2O to supply hot water up to 176 F even in low ambient conditions without burning fossil fuels.