Why aren’t we piping the heat from air-con compressor / coolant units to heaters yet?

Was wondering … why aren't we piping the heat from air-con compressors / coolant units to heaters yet?

These units are transferring heat from the room or fridge to the coolant gas and onto the air surrounding the unit.  Go check out the back of your fridge or the compressor unit of your split-unit aircon . . . → Read More: Why aren’t we piping the heat from air-con compressor / coolant units to heaters yet?