Existing propane systems were replaced with a WaterFurnace Synergy 3D unit and Intellizone control. The Synergy 3D unit will provide heating, A/C, domestic hot water, as well as hot water for radiant floor heat. The Intellizone system allows for independent temperature control both upstairs and down. As with almost all (of our) open loop systems, no back-up electric heat elements are installed. This home is heated entirely with the geothermal heat pump at 427% efficient (as measured at start-up).