Siebring Heaters SIEBRING HEATERS USGR is pleased to provide a wide range of Siebring heating products for greenhouses, nurseries, garden centers, shops, maintenance buildings, and other outbuildings application. We are a leading supplier of commercial horticultural and agricultural heaters as well as commercial and industrial heaters. Our products are used nationwide and worldwide by commercial greenhouses, nurseries, garden centers, shops, maintenance building, auto & truck repair shops and other outbuilding applications. Our Siebring fully automatic heaters are sized right to meet your needs for efficient, dependable general purpose heating. Available in Propane, Natural Gas and Diesel Oil. Siebring Oil Heaters: Heatmaster Classic Oil Heater Quantum Oil Heater Royal Oil Heater Military 401 Furnace Siebring Natural Gas / Propane Heaters: Quantum Propane / Natural Gas Heater Royal Propane / Natural Gas Heater To assist you in your planning and purchase of a Siebring Heating System, please visit our Siebring Furnace Vents, Sizing, and Safety page.