EcoSmart ECO 36
#1 in ElectricFull review
For a large home with 300 A service that wants all electric hot water. The lifetime warranty and low price per kilowatt make it a strong value if a pro installs it.
Amazon $699$699
The EcoSmart ECO 36 is the better tankless water heater overall, rated 4.3 to 3.8. The EcoSmart ECO 36 leads on warranty, heating power and value. The Stiebel Eltron Tempra 29 Trend wins on efficiency. The Stiebel Eltron Tempra 29 Trend costs $59.01 less ($639.99 vs $699).
Stiebel Eltron Tempra 29 Trend
#3 in ElectricFull review
For homes with 200 A service in mild climates that want two showers at once from one heater.
Amazon $639.99$639.99
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 36 for warranty (limited lifetime heat exchanger warranty vs 7-year heat exchanger warranty), heating power (36 kW vs 28.8 kW) and value ($19.42 per kW ($699, 36 kW) vs $22.22 per kW ($639.99, 28.8 kW)).
- Choose the Stiebel Eltron Tempra 29 Trend for efficiency (0.98 UEF vs 0.94 UEF).
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 36 | Stiebel Eltron Tempra 29 Trend |
|---|---|---|
| Overall rating | 4.3/5 | 3.8/5 |
| Value 35% | 64 $19.42 per kW ($699, 36 kW) | 53 $22.22 per kW ($639.99, 28.8 kW) |
| Heating power 25% | 100 36 kW | 71 28.8 kW |
| Efficiency 15% | 50 0.94 UEF | 100 0.98 UEF |
| Warranty 25% | 100 limited lifetime heat exchanger warranty | 57 7-year heat exchanger warranty |
Specifications
| EcoSmart ECO 36 | Stiebel Eltron Tempra 29 Trend | |
|---|---|---|
| Heating | ||
| Fuel | Electric | Electric |
| Electric power | 36 kW | 28.8 kW |
| Max flow | 8.8 GPM | 6 GPM |
| UEF | 0.94 | 0.98 |
| Installation | ||
| Voltage | 240 V | 240 V |
| Breakers | 160 A total | 120 A total |
| Weight | 18.4 lb | 19 lb |
| Features | ||
| Built-in recirculation | No | No |
| Wi-Fi | No | No |
| Heat exchanger warranty | Limited lifetime | 7 years |
| Parts warranty | - | 3 years |