A dual fuel heating system combines a heat pump with a gas furnace. Many houses are equipped with heat pumps, which transfers heat from one place to another. For example, an air conditioner is a heat pump that takes the heat from the air inside your house and releases that heat into the outside air. Most heat pump systems work like an air conditioner in the summer, then can be reversed to move heat into your house during cooler months. However, heat pumps do not work well when the outside air is too cold, typically below freezing. A dual fuel system includes a gas furnace, which takes over providing heat when it gets too cold for the heat pump. Your Lyric is compatible with most dual fuel heating systems. Your Lyric app will walk you through configuring your Lyric to work with your heating system.