Bosch
Bosch Greentherm T9900i SE 199
$3583.27
Best Tankless Water Heaters · head-to-head
Bosch Greentherm T9900i SE 199 vs A.O. Smith ProLine XE ATI-540H-N
A sourced, side-by-side comparison. Bosch Greentherm T9900i SE 199 is cheaper at $3583.27. Every spec and price links to its source.
A.O. Smith
A.O. Smith ProLine XE ATI-540H-N
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Full spec sheet
✓ marks the stronger figure where "more" — or "less", for price and weight — is unambiguously better.
| Spec |  Bosch Greentherm T9900i SE 199 |  A.O. Smith ProLine XE ATI-540H-N |
|---|---|---|
| US price | $3583.27 | — |
| Brand | Bosch | A.O. Smith |
| Released | — | — |
| Fuel type | natural-gas | natural-gas |
| Max flow rate (gpm) | 11.2 | 10 |
| Max btu per hour | 199000 | 199000 |
| Power input (kW) | — | — |
| Uniform energy factor | — | 0.93 |
| Condensing type | condensing | condensing |
| Min activation flow (gpm) | 0.45 | — |
| Vent type | pvc | pvc |
| Max temp (°F) | 140 | — |
| Heat exchanger warranty yrs | 15 | 15 |
| Wi-Fi enabled | Yes | — |
| Weight (lb) | 85 | — |
Sources — Bosch Greentherm T9900i SE 199: bosch-homecomfort.com (verified 2026-07-11). A.O. Smith ProLine XE ATI-540H-N: hotwater.com (verified 2026-07-11).
What's the difference between the Bosch Greentherm T9900i SE 199 and A.O. Smith ProLine XE ATI-540H-N?
Where the two actually differ on the specs we track (1 of 12). Matching specs are omitted.
- Max flow rate (gpm): Bosch Greentherm T9900i SE 199 11.2 vs A.O. Smith ProLine XE ATI-540H-N 10