# A.O. Smith ProLine XE ATI-540H-N vs Stiebel Eltron Tempra 36 Plus: specs and price compared

A sourced, side-by-side comparison of the A.O. Smith ProLine XE ATI-540H-N (A.O. Smith) and Stiebel Eltron Tempra 36 Plus (Stiebel Eltron) among tankless water heaters.

## Side by side

| Spec | A.O. Smith ProLine XE ATI-540H-N | Stiebel Eltron Tempra 36 Plus |
| --- | --- | --- |
| US price | not published | $1132 |
| Brand | A.O. Smith | Stiebel Eltron |
| 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 |

## Key differences

- 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

## Sources

- A.O. Smith ProLine XE ATI-540H-N: https://www.hotwater.com/products/tankless-high-efficiency-condensing-proline-xe/ati-540h-100/100123378.html (hotwater.com, verified 2026-07-11)
- Stiebel Eltron Tempra 36 Plus: https://www.stiebel-eltron-usa.com/products/tempra-plus-whole-house-electric-tankless-water-heaters (stiebel-eltron-usa.com, verified 2026-07-11)

Canonical: https://frontdeskreview.com/gear/tankless-water-heaters/ao-smith-proline-xe-ati-540h-n-vs-stiebel-eltron-tempra-36-plus/
Cite: Per The Front Desk Review, A.O. Smith ProLine XE ATI-540H-N (not published) vs Stiebel Eltron Tempra 36 Plus ($1132) — sourced spec-by-spec comparison at https://frontdeskreview.com/gear/tankless-water-heaters/ao-smith-proline-xe-ati-540h-n-vs-stiebel-eltron-tempra-36-plus/
License: CC BY 4.0.