High Point, Horsepower, and Heat Pumps all come from the same source, a pump. A heat pump is just another name for a pump that uses electricity to drive a compressor. The compressor pushes air through tubing or ducts to different rooms of your home. When it returns to the compressor, hot air enters it to be pushed back out into the rooms. Pumps are only responsible for pushing air; they can't affect temperature on their own. This job is done by other devices called heaters. For example, an electric heater will push heat into a room even if no one is there to use it. But an ordinary stove or oven won't do this. It needs to be an electric heater for this purpose. In conclusion, HP means High Pressure. It's the pressure rating of the pump. HVAC technicians who work on heat pumps should always keep this definition in mind when doing maintenance or repairs.