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 EcoSmart ECO 24
A sourced, side-by-side comparison. EcoSmart ECO 24 is cheaper at $525. Every spec and price links to its source.
EcoSmart
EcoSmart ECO 24
$525
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 |  EcoSmart ECO 24 |
|---|---|---|
| US price | — | $525 |
| Brand | A.O. Smith | EcoSmart |
| Released | — | — |
| Fuel type | natural-gas | electric |
| Max flow rate (gpm) | 10 | — |
| Max btu per hour | 199000 | — |
| Power input (kW) | — | 24 |
| Uniform energy factor | 0.93 | — |
| Condensing type | condensing | electric |
| Min activation flow (gpm) | — | 0.3 |
| Vent type | pvc | none |
| Max temp (°F) | — | 140 |
| Heat exchanger warranty yrs | 15 | — |
| Wi-Fi enabled | — | No |
| Weight (lb) | — | 14.25 |
Sources — A.O. Smith ProLine XE ATI-540H-N: hotwater.com (verified 2026-07-11). EcoSmart ECO 24: ecosmartus.com (verified 2026-07-11).
What's the difference between the A.O. Smith ProLine XE ATI-540H-N and EcoSmart ECO 24?
Where the two actually differ on the specs we track (3 of 12). Matching specs are omitted.
- Fuel type: A.O. Smith ProLine XE ATI-540H-N natural-gas vs EcoSmart ECO 24 electric
- Condensing type: A.O. Smith ProLine XE ATI-540H-N condensing vs EcoSmart ECO 24 electric
- Vent type: A.O. Smith ProLine XE ATI-540H-N pvc vs EcoSmart ECO 24 none