A gas powered heat delivery system, comprising a fuel gas supply, a catalytic heater connected to the fuel gas supply; a tank containing fluid, the tank being disposed to receive heat from the catalytic heater; a one way conduit having an inlet for receiving fluid from the tank, an outlet for delivering fluid to the tank, and a heat delivery section; a rolling diaphragm pump connected to the one way conduit for pumping heated fluid through the one way conduit from inlet to outlet, the rolling diaphragm pump being connected to the fuel gas supply to operate the rolling diaphragm pump; and a switch for switching the fuel gas supply between the rolling diaphragm pump and the catalytic heater, the switch being operated by the rolling diaphragm pump. Propane may be used as the fuel gas. Glycol may be used as the heating fluid. The gas powered heat delivery system may be used to heat oilfield equipment, for example at a well site, or items in other environments, particularly where vapors pose an explosion hazard.