PRODUCT GUIDE Solar Thermal This 36,597 ft2 Ritter XL solar thermal system is installed on an exhibition hall in Wels, Austria and provides almost 7 million Btu/hr of supplemental hot water for district heating. Photo: Ritter Gruppe Behind the recommendations Related articles Behind the recommendations Related articles Solar Thermal The highest-rated solar thermal collectors, components, and packaged systems on the market More about Solar Thermal Solar Thermal Hot Water, Heating, and Cooling By creating heat instead of electricity, solar thermal achieves three times the efficiency of photovoltaics at a lower price. The World's Most Efficient Solar Thermal Collector? A Cutting-Edge Hybrid Solar-Thermal-PV Collector from Turkey Picking a Water Heater: Solar vs. Electric or Gas Is Just the Beginning Why we opted for electric water heating over a solar water heater.