A heat pump is an HVAC system that can both heat and cool. It extracts and moves heat between the inside and outside air. In the summer, the heat pump works like an AC unit, just like a traditional air conditioner. In the winter, it reverses this process, absorbing heat from the outside air (even in cold temperatures) and transferring it inside to warm your home. Heat pumps are highly efficient for both heating and cooling, making them a good alternative to traditional furnaces and air conditioners, especially in mild to moderate climates.