EcoSmart and Stiebel Eltron compete in the whole-house electric tankless segment from opposite ends — EcoSmart wins on price and warranty length; Stiebel Eltron wins on Flow Control technology and cold-climate performance.
Side-by-side
| Stiebel Tempra 29 Plus | EcoSmart ECO 27 | |
|---|---|---|
| kW | 28.8 | 27 |
| Modulation | Flow Control | Self-Modulating (constant power) |
| Element | Solid copper | Threaded stainless |
| Heat exchanger warranty | 7 years | Lifetime (residential) |
| Parts warranty | 3 years | 5 years |
| Origin | Germany | USA |
| Typical price | $849-1,049 | $549-699 |
Where Stiebel wins
- Flow Control modulation — fundamentally different technology vs constant-power EcoSmart
- Cold-climate performance — Stiebel rules where EcoSmart struggles
- Solid copper elements — more durable in hard water than threaded stainless
- German build quality — visible in fit, finish, controls
- Better tech support — direct factory engineers; EcoSmart support varies
Where EcoSmart wins
- Lifetime residential heat exchanger warranty — strongest in the category on paper
- Lower price — typically 30-40% less than equivalent Tempra Plus
- US manufacturing — appeals to domestic-preference buyers
- 5-year parts warranty — longer than Stiebel\'s 3-year
- Wider availability — Home Depot, Lowe\'s, Amazon stock
The EcoSmart warranty caveat
EcoSmart\'s lifetime heat exchanger warranty has conditions:
- Residential use only (commercial = 5 years)
- Element-related failures only (some other failure modes excluded)
- Annual descaling documented in hard water
- Original homeowner only (non-transferable to next owner)
Read the warranty terms carefully. In practice, EcoSmart honors most legitimate claims but the "lifetime" is conditional, not unconditional.
Cold-climate performance gap
The most important practical difference: cold-climate performance. With 40°F incoming water and 3 GPM demand:
- EcoSmart ECO 27: outputs water at ~104°F (tepid)
- Stiebel Tempra 29 Plus: reduces flow to 2 GPM and outputs at 120°F (hot)
For Sun Belt installs where incoming water is 65-72°F year-round, EcoSmart is fine. For Mid-Atlantic and colder, Stiebel\'s Flow Control is materially valuable.
Which to choose
- Sun Belt + budget: EcoSmart
- Cold-climate + premium acceptable: Stiebel
- Lifetime warranty decisive + warm climate: EcoSmart
- Want Flow Control + Quality engineering: Stiebel
- DIY install priority: EcoSmart (more contractor familiarity)
Bottom line
EcoSmart is the value play with the longest paper warranty. Stiebel is the premium play with materially better cold-climate technology. Climate is the deciding factor — warm climates make EcoSmart competitive; cold climates require Stiebel Flow Control.