Hot Water Heat Pump

• CO2 based - R744 - Arctic heat pumps - air to water - 48000 BTU only $6k - [1]. 60k BTU $6k [2]
• 15000 BTU - 65C max - [3]. $3500 for the heat pump outdoor unit only [4], $5400 for system [5]. Outdoor unit already has water heat exchanger, so that's all we need. 1700W usage! One 6kW inverter runs 3 of these.
• Rheem Performance Platinum - has heat pump only mode, heat pump is only 4200BTU. [6] (1.2kW heat pump + 4500 electric element)
• Accelera, $3k, only 1800W heat pump output [7]
• Ruud - 4200 BTU compressor = $1664. If get 6 of these, that is $10k. [8]