Hybrid systems that can use basic ideas of heat transfer have enormous possibilities for growth. There are a few great sources of heat in and around your home that you can capture and use to your advantage. For example, solar thermal panels can produce large amounts of heat during the day, which is a great thing to use in your heating system. You could use that hot water to pre-heat the water that enters a heat pump, which raises its efficiency, or pipe it to exchange heat with your radiant heating system. Any kind of use for sources of heat can be a great idea in a home.