* A/Cs are heat-pumps (when using the scientific definition of "heat-pump") * Heat pumps, when referring to HVAC technology specifically, refer to systems that

* A/Cs are heat-pumps (when using the scientific definition of "heat-pump") * Heat pumps, when referring to HVAC technology specifically, refer to systems that are essentially the same as A/C units, except they're designed to work in reverse. * The term "heat pump" when used in Europe, more-often refers to geothermal heat-pumps ( https://en.wikipedia.org/wiki/Ground_source_heat_pump https://en.wikipedia.org/wiki/Ground_source_heat_pump ) which is very different to an A/C-style heat-pump, though achieves similar end-result (livable indoor room air temperature). As someone who spends a lot of time in the year in both North America and Europe I frequently come across people confusing the two.