A heat pump is a device that uses a small amount of energy to move heat from one location to another. Heat pumps are typically used to pull heat out of the air or ground to heat a home or office building, but they can be reversed to cool a building.
One of the biggest advantages of a heat pump over a standard heating ventilating and air conditioning (HVAC) unit is that there's no need to install separate systems to heat and cool your home. Heat pumps also work extremely efficiently, because they simply transfer heat, rather than burn fuel to create it. Heat pumps work best in moderate climates, so if you don't experience extreme heat and cold in your neck of the woods, then using a heat pump instead of a furnace and air conditioner could be a good way for you to go.
The heat produced by heat pumps isn't as intense as the heat produced by a gas or oil-burning furnace. People who are used to traditional furnaces can be uncomfortable with the milder heat produced by these systems. Other people prefer the warmth produced by heat pumps, because heat pumps distribute heat evenly throughout the house, meaning there are no cold spots. A heat pump will also turn on and off less often than a gas furnace, and most systems have eliminated the blowing of cold air through the vents that used to occur when the system temporarily switched into reverse to defrost the coils.