WaterFurnace Geothermal heating and cooling systems come in three basic configurations plus a fourth combo type, designed to meet the needs of your home and provide the highest efficiency and the greatest energy savings. And nearly all of our products meet or exceed the ENERGY STAR® requirements. Forced Air All-In-One, Radiant, Hot Water & Hydronic Indoor/Outdoor Split, and Forced Air / Hydronic Combo. WaterFurnace systems are rated number one in energy efficiency because they can deliver more than five units of energy for every one unit of electrical energy used. Compared to even the best ordinary system, it translates into an efficiency rating exceeding 530%.