I've never owned one, but the physics are pretty straightforward. The greater concern is longevity. I seem to recall a refrigerated air unit will use about 15

I've never owned one, but the physics are pretty straightforward. The greater concern is longevity. I seem to recall a refrigerated air unit will use about 15% of its energy to cool its hot side and about 85% to pump the heat from cold side to hot side. So even if this eliminates that entire 15%, you're still going to be putting a lot of juice into that heat pump.