EcoSmart ECO 11
#5 in ElectricFull review
For a single shower or a pair of sinks in a warm climate, with a lifetime warranty if a pro installs it.
Amazon $244.78$244.78
The EcoSmart ECO 11 is the better tankless water heater overall, rated 3.4 to 3.2. The EcoSmart ECO 11 leads on value and warranty. The Stiebel Eltron Tempra 20 Trend wins on efficiency and heating power. The EcoSmart ECO 11 costs $299.65 less ($244.78 vs $544.43).
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
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 EcoSmart ECO 11 for value ($18.83 per kW ($244.78, 13 kW) vs $28.36 per kW ($544.43, 19.2 kW)) and warranty (limited lifetime heat exchanger warranty vs 7-year heat exchanger warranty).
- Choose the Stiebel Eltron Tempra 20 Trend for efficiency (0.97 UEF vs 0.92 UEF) and heating power (19.2 kW vs 13 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 | EcoSmart ECO 11 | Stiebel Eltron Tempra 20 Trend |
|---|---|---|
| Overall rating | 3.4/5 | 3.2/5 |
| Value 35% | 66 $18.83 per kW ($244.78, 13 kW) | 35 $28.36 per kW ($544.43, 19.2 kW) |
| Heating power 25% | 8 13 kW | 33 19.2 kW |
| Efficiency 15% | 25 0.92 UEF | 87 0.97 UEF |
| Warranty 25% | 100 limited lifetime heat exchanger warranty | 57 7-year heat exchanger warranty |
Specifications
| EcoSmart ECO 11 | Stiebel Eltron Tempra 20 Trend | |
|---|---|---|
| Heating | ||
| Fuel | Electric | Electric |
| Electric power | 13 kW | 19.2 kW |
| Max flow | 3.2 GPM | 4 GPM |
| UEF | 0.92 | 0.97 |
| Installation | ||
| Voltage | 240 V | 240 V |
| Breakers | 60 A total | 80 A total |
| Weight | 6.5 lb | 16.1 lb |
| Features | ||
| Built-in recirculation | No | No |
| Wi-Fi | No | No |
| Heat exchanger warranty | Limited lifetime | 7 years |
| Parts warranty | - | 3 years |