Stiebel Eltron Tempra 20 Trend
#9 in ElectricFull review
For a small home or apartment in a warm climate with 125 A service. The Tempra 24 costs little more and gives more headroom.
Amazon $544.43$544.43
The Stiebel Eltron Tempra 20 Trend is the better tankless water heater overall, rated 3.2 to 2.9. The Stiebel Eltron Tempra 20 Trend leads on warranty and efficiency. The EcoSmart ECOS 18 wins on value. The EcoSmart ECOS 18 costs $95.43 less ($449 vs $544.43).
EcoSmart ECOS 18
#14 in ElectricFull review
For a small home or apartment in a warm climate that wants whole house hot water on two breakers. Amazon stock was low when checked.
Amazon $449$449
Prices were last checked October 31, 2026 and are subject to change; the price and availability shown by the retailer at the time of purchase apply.
Which should you buy?
- Choose the Stiebel Eltron Tempra 20 Trend for warranty (7-year heat exchanger warranty vs 5-year heat exchanger warranty) and efficiency (0.97 UEF vs 0.96 UEF).
- Choose the EcoSmart ECOS 18 for value ($24.94 per kW ($449, 18 kW) vs $28.36 per kW ($544.43, 19.2 kW)).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every electric tankless water heater; a clear win is highlighted. How we rank explains each one.
| Factor weight | Stiebel Eltron Tempra 20 Trend | EcoSmart ECOS 18 |
|---|---|---|
| Overall rating | 3.2/5 | 2.9/5 |
| Value 35% | 35 $28.36 per kW ($544.43, 19.2 kW) | 45 $24.94 per kW ($449, 18 kW) |
| Heating power 25% | 33 19.2 kW | 28 18 kW |
| Efficiency 15% | 87 0.97 UEF | 75 0.96 UEF |
| Warranty 25% | 57 7-year heat exchanger warranty | 29 5-year heat exchanger warranty |
Specifications
| Stiebel Eltron Tempra 20 Trend | EcoSmart ECOS 18 | |
|---|---|---|
| Heating | ||
| Fuel | Electric | Electric |
| Electric power | 19.2 kW | 18 kW |
| Max flow | 4 GPM | 4.4 GPM |
| UEF | 0.97 | 0.96 |
| Installation | ||
| Voltage | 240 V | 240 V |
| Breakers | 80 A total | 80 A total |
| Weight | 16.1 lb | 9.3 lb |
| Features | ||
| Built-in recirculation | No | No |
| Wi-Fi | No | No |
| Heat exchanger warranty | 7 years | 5 years |
| Parts warranty | 3 years | 1 year |