In theory. Remember that the motor of the heat pump isn’t 100% efficient. It’s still an electric motor. That’s is of course offset by it not generating heat but

In theory. Remember that the motor of the heat pump isn’t 100% efficient. It’s still an electric motor. That’s is of course offset by it not generating heat but rather transferring it. So say you’re electric motor is 33% efficient. That means you need a 3x multiplier to break even with a resistive load. And the multiplier depends on the temperature difference between inside and outside. If it’s 70F inside and 50F outside you are golden. If it is -10F outside, you are better off using a resistive load.