🤓 ACKSHUALLY

It's not possible for a heat pump - or anything - to even be 100% efficient, let alone 400%. Efficiency is measure of how much of the input energy gets converted to useful output energy, and since heat pumps don't actually create heat the useful output is the compressor's ability to pump refrigerant about. The Coefficient of Performance - the ratio between energy put in and useful work done - is 400% for a heat pump (give or take).