A.O. Smith
A.O. Smith ProLine XE ATI-540H-N
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Best Tankless Water Heaters · head-to-head
A.O. Smith ProLine XE ATI-540H-N vs Stiebel Eltron Tempra 36 Plus
A sourced, side-by-side comparison. Stiebel Eltron Tempra 36 Plus is cheaper at $1132. Every spec and price links to its source.
Stiebel Eltron
Stiebel Eltron Tempra 36 Plus
$1132
Full spec sheet
✓ marks the stronger figure where "more" — or "less", for price and weight — is unambiguously better.
| Spec |  A.O. Smith ProLine XE ATI-540H-N |  Stiebel Eltron Tempra 36 Plus |
|---|---|---|
| US price | — | $1132 |
| Brand | A.O. Smith | Stiebel Eltron |
| Released | — | — |
| Fuel type | natural-gas | electric |
| Max flow rate (gpm) | 10 | 8.2 |
| Max btu per hour | 199000 | — |
| Power input (kW) | — | 36 |
| Uniform energy factor | 0.93 | — |
| Condensing type | condensing | electric |
| Min activation flow (gpm) | — | 0.77 |
| Vent type | pvc | none |
| Max temp (°F) | — | 140 |
| Heat exchanger warranty yrs | 15 | 7 |
| Wi-Fi enabled | — | No |
| Weight (lb) | — | 17.6 |
Sources — A.O. Smith ProLine XE ATI-540H-N: hotwater.com (verified 2026-07-11). Stiebel Eltron Tempra 36 Plus: stiebel-eltron-usa.com (verified 2026-07-11).
What's the difference between the A.O. Smith ProLine XE ATI-540H-N and Stiebel Eltron Tempra 36 Plus?
Where the two actually differ on the specs we track (5 of 12). Matching specs are omitted.
- Fuel type: A.O. Smith ProLine XE ATI-540H-N natural-gas vs Stiebel Eltron Tempra 36 Plus electric
- Max flow rate (gpm): A.O. Smith ProLine XE ATI-540H-N 10 vs Stiebel Eltron Tempra 36 Plus 8.2
- Condensing type: A.O. Smith ProLine XE ATI-540H-N condensing vs Stiebel Eltron Tempra 36 Plus electric
- Vent type: A.O. Smith ProLine XE ATI-540H-N pvc vs Stiebel Eltron Tempra 36 Plus none
- Heat exchanger warranty yrs: A.O. Smith ProLine XE ATI-540H-N 15 vs Stiebel Eltron Tempra 36 Plus 7