High performance, high efficiency, and highly serviceable. Hubbell Gas-HX is our fully modulating 316L stainless steel heat exchanger. Ideal for gas-fired water heater applications with natural gas or propane fuel sources. It performs at up to 94% efficiency with 55,000 BTU/HR input. Gas-HX is field-serviceable and removable. This makes service work easy and helps sustain peak component performance.