Ideal for large commercial applications, the Cyclone XL commercial gas water heater operates at 1-million Btu/h, with an additional 750,000 Btu/h model available. Its ability to adjust the firing rate to meet demand further increases efficiency and cost savings, A. O. Smith notes. Cyclone XL features a unique dual stainless steel heat exchange system, providing a two-step heat transfer process that delivers thermal efficiency of 97%.