AO Smith Cyclone Mxi 100-Gallon Commercial Gas Water Heater

The AO Smith Cyclone Mxi 100-Gallon Commercial Gas Water Heater (BTH-150) is the volume commercial gas tank for restaurants, laundries, light hotels, multi-family residential, and large single-family estates with 7+ person households. 150,000 BTU helical-fin Cyclone burner, 0.94 thermal efficiency, 290 GPH first-hour delivery, 290 gallons-per-hour recovery at 90°F rise. Commercial 3-year warranty.

Headline specifications

• Capacity: 100 gallons
• Fuel: Natural gas, power vent or atmospheric (model-dependent)
• BTU input: 150,000 BTU/h
• First Hour Delivery: 290 GPH
• Recovery: 173 GPH at 90°F rise
• Thermal efficiency: 94%
• Warranty: 3-year commercial tank, 1-year parts
• Anode: Coregard, multiple
• Dimensions: 74" H × 30" diameter
• Inlet/outlet: 1-1/4" NPT (commercial sizing)

Who this model is for

Light-commercial applications: 12–20 unit apartment buildings (sized correctly), 40-seat restaurants, 8–12 station hair salons, in-home daycares serving 8+ kids, B&Bs with 4–6 rooms. Single-family residential is overkill unless you're running 7+ person estate-class loads (8+ bathrooms, two-zone HVAC, hot-tub or pool spa-fill demand).

Most residential buyers should not consider the Cyclone — the commercial 3-year warranty is shorter than residential 6–10 year, and the install footprint is much larger. For estate-class residential, the ProLine Master 75G is usually correct. Pivot to Cyclone only if peak demand exceeds 113 GPH FHD.

Where it beats the alternatives

Vs dual Signature Premier 50G cascade: single 100G is simpler maintenance, single vent, single gas drop. Dual 50G adds redundancy (one fails, the other carries) at higher install complexity. Light-commercial typically picks the single 100G.

Vs commercial tankless cascade (e.g. dual RU199iN): tankless cascade ~$3,400 hardware + $4,500 install vs Cyclone ~$2,800 hardware + $2,400 install. Tankless wins on efficiency (0.96 vs 0.94 — wash) and operating cost long-term. Tank wins on upfront and simplicity.

Vs State SBN100 100G Commercial ($2,649): same AO Smith manufacturing through plumber channel. Same hardware, same warranty. Tie-breaker on installer preference.

Where it falls short

3-year commercial tank warranty is short. Residential warranties run 6–12 years. Commercial buyers accept the trade because the duty cycle exceeds residential.

74" height + 30" diameter is large. Verify install location and clearance.

1-1/4" NPT inlet/outlet means commercial plumbing — not a residential DIY swap. Permit and licensed commercial plumber required in most jurisdictions.

150,000 BTU input requires sized gas line — typically 1" or larger, not 3/4".

For estate-class residential where the Cyclone is overkill, the smaller ProLine Master 75G at 113 GPH FHD with 10-year residential warranty is the correct sizing decision.

Install considerations

Commercial install: 1" or 1-1/4" gas line, 4" double-wall vent (or 6" PVC for power-vent variants), 1-1/4" NPT plumbing, permit required, commercial-certified installer required. Mixing valve recommended for commercial scald protection.

Install cost: $2,000–$4,500 like-for-like commercial swap; significantly higher for new construction or upgrade from residential.

Maintenance

• Quarterly flush for high-duty-cycle commercial
• Multi-anode check year 2, replace year 3–4
• T&P valve test quarterly in commercial
• Annual burner and combustion inspection by licensed technician
• Scale inspection on heat exchanger annually in hard-water regions

Bottom line

The AO Smith Cyclone Mxi 100G is the volume commercial gas tank for light-commercial and estate-class residential. 290 GPH FHD, 94% efficiency, 150,000 BTU Cyclone burner. Right pick when peak demand exceeds the 113 GPH FHD of the residential ProLine Master 75G. Commercial 3-year warranty reflects duty-cycle expectations. For residential single-family use, the smaller ProLine Master is almost always the right sizing.