In part one of this episode from the Green Architects' Lounge, we only scratched the surface. Now it's time to really dig in and decide if a ground source heat pumpHeating and cooling system in which specialized refrigerant fluid in a sealed system is alternately evaporated and condensed, changing its state from liquid to vapor by altering its pressure; this phase change allows heat to be transferred into or out of the house. See air-source heat pump and ground-source heat pump. system is right for you and if so, to start planning for it.