Free standard shipping on orders over $149.97
The EcoSmart tankless water heater range is a popular value choice for electric homes. Here’s how to pick the right ECO or POU model.
Shoppers search for the EcoSmart 11-kW tankless electric water heater, the EcoSmart ECO 18 electric tankless water heater and the EcoSmart electric tankless water heater ECO 27 most often. An eco smart tankless water heater is the same brand.
| Model | Approx. power | Approx. amps at 240V | Typical use |
|---|---|---|---|
| POU 3.5 and other POU models | 3.5–6 kW (some 120V) | 15–25 A | One sink |
| ECO 8 / ECO 11 | Small whole-unit models | See label | One fixture, warm climates |
| ECO 18 | 18 kW | 75 A | One shower or small home, warm climates |
| ECO 24 / ECO 27 | 24–27 kW | 100–113 A | 1–2 bathrooms, warm to mild climates |
| ECO 36 | 36 kW | 150 A | Whole house, warm climates |
Amperage is calculated from kW at 240V. The manual for each model lists exact breaker sizes and wire gauge. If you searched for the "EcoSmart 11 kW", check the product label or spec sheet for the exact power rating of the model you’re looking at.
Flow depends on temperature rise. For example, at a 45°F rise (warm climate), an ECO 27 can heat about 4 GPM; at a 75°F rise (cold climate), about 2.5 GPM. Our sizing guide has a full chart.
An ECO 36 tankless water heater delivers about 5.5 GPM at a 45°F rise, while the EcoSmart POU 3.5 point of use electric tankless water heater is designed for a single sink.
Have an electrician confirm capacity first. See installation requirements.
Compare with the Stiebel Eltron Tempra line, known for advanced flow control, and Rheem RTEX models. If you have gas, a gas tankless unit will deliver more flow in cold climates.
Every listing shows kW, amperage, breakers and flow.
For a whole house in a warm climate, the ECO 27 or ECO 36. For a single shower or apartment in a warm climate, the ECO 18 may be enough. For one sink, a POU model. Cold climates need more kW for the same flow; use our sizing calculator.
A 27 kW unit draws about 113 amps at 240V, typically across several double-pole breakers. The installation manual lists the exact breakers and wire gauge.
EcoSmart is widely sold and popular for its price. Owners report the best results when the unit is correctly sized for their climate and the electrical installation follows the manual.
In warm climates it can run a low-flow shower; in cold climates its flow will be limited. It is best suited to one fixture or a small apartment in a mild climate.
This guide is general information for U.S. homeowners, not professional advice. Gas, electrical and venting work must follow the manufacturer’s instructions and local codes, and in most areas requires a licensed plumber, electrician or gas fitter and a permit. Specifications and prices change; always confirm details on the product page and in the installation manual.
