Bosch Tankless Water Heaters Therm Pro Line in Natural Gas and Propane Gas supply homeowners with the energy-efficient, endless supply of hot water. Only gas tankless water heaters can deliver this kind of output with high efficiency. Bosch Tankless Water Heaters in Propane (LP) or Natural Gas (NG). The Bosch Pro Therm Line must only be installed by Licensed Installers.
