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 2.6. The EcoSmart ECO 11 leads on warranty and value. The Bosch Tronic 6100 C 18 wins on heating power and efficiency. The EcoSmart ECO 11 costs $340.68 less ($244.78 vs $585.46).
Bosch Tronic 6100 C 18
#16 in ElectricFull review
For a small home or apartment in a warm climate that wants the Bosch name. Most buyers get more power for the money elsewhere.
Amazon $585.46$585.46
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 warranty (limited lifetime heat exchanger warranty vs 5-year heat exchanger warranty) and value ($18.83 per kW ($244.78, 13 kW) vs $32.53 per kW ($585.46, 18 kW)).
- Choose the Bosch Tronic 6100 C 18 for heating power (18 kW vs 13 kW) and efficiency (0.94 UEF vs 0.92 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 11 | Bosch Tronic 6100 C 18 |
|---|---|---|
| Overall rating | 3.4/5 | 2.6/5 |
| Value 35% | 66 $18.83 per kW ($244.78, 13 kW) | 25 $32.53 per kW ($585.46, 18 kW) |
| Heating power 25% | 8 13 kW | 28 18 kW |
| Efficiency 15% | 25 0.92 UEF | 50 0.94 UEF |
| Warranty 25% | 100 limited lifetime heat exchanger warranty | 29 5-year heat exchanger warranty |
Specifications
| EcoSmart ECO 11 | Bosch Tronic 6100 C 18 | |
|---|---|---|
| Heating | ||
| Fuel | Electric | Electric |
| Electric power | 13 kW | 18 kW |
| Max flow | 3.2 GPM | 3.5 GPM |
| UEF | 0.92 | 0.94 |
| Installation | ||
| Voltage | 240 V | 240 V |
| Breakers | 60 A total | 90 A total |
| Weight | 6.5 lb | 14.8 lb |
| Features | ||
| Built-in recirculation | No | No |
| Wi-Fi | No | No |
| Heat exchanger warranty | Limited lifetime | 5 years |
| Parts warranty | - | 2 years |
| Released | - | 2023-01 |