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AO Smith Cyclone Water Heater — Specs, Features & Reviews

AO Smith's commercial-residential and light-commercial gas line. BTH and FCG series.

Updated May 2026 · AO Smith Water Heaters

The Cyclone Xi series is AO Smith's commercial-residential and light-commercial gas water heater line — high-capacity, high-BTU tanks for restaurants, multi-family residential, in-home daycares, B&Bs, and estate-class residential.

The Cyclone Xi lineup

Cyclone Xi technology

The Cyclone Xi uses helical-fin tube heat exchanger technology for 95-96% thermal efficiency. Combined with intelligent ignition and modulating gas control, it's one of the most efficient commercial gas tank designs available.

Commercial warranty

3-year tank, 1-year parts — commercial duty cycle. See our warranty hub.

When commercial overkill applies

For estate-class residential at 7+ occupants, the ProLine Master 75G at 10-year residential warranty is usually correct sizing instead of Cyclone Xi. Step into Cyclone Xi only when peak demand truly exceeds 115 GPH FHD.

Bottom line

Cyclone Xi is for: small restaurants, hair salons, in-home daycares, 12-20 unit apartment buildings, B&Bs with 4+ rooms. Commercial-certified installer required.