EcoSmart ECO 18 18kW Electric Tankless Water Heater

The EcoSmart ECO 18 is the mid-size of EcoSmart's whole-house electric tankless line, sitting between the ECO 11 (single-bathroom homes) and the ECO 27 (whole-house in cold climates). At 18 kW with two 40-amp double-pole breakers, it pulls 75 amps total at 240V — the same draw as the Rheem RTEX-18 but distributed across two feeds rather than one. Capacity at the tap: about 3.0 GPM at a 40°F rise (southern winter) or 2.0 GPM at a 60°F rise (northern winter). Right-sized for a 1–2 bathroom home in any US climate or a 2-bathroom home in the Sun Belt.

Distinguishing features versus competitor electric tankless units are the lifetime warranty on the heat exchanger plus 5-year warranty on electronics (most competitors warranty electronics for 1–3 years), the patented self-modulating technology that adjusts power in 0.25 kW increments, and the stainless steel heat exchanger that resists scale buildup in hard water roughly 2× longer than copper-exchanger competitors. Service is direct through EcoSmart — they ship replacement parts to homeowners, and most common failures (flow sensor, thermistor) are user-replaceable in under 30 minutes.

The honest fit assessment: the ECO 18 is the right choice for households with 200A service, soft-to-moderate hardness, and demand profiles that don't require two simultaneous showers in winter. Households in the North with 100A panels should look at the ECO 11 (smaller demand) or a heat-pump tank instead. Households in the North with 200A service and overlapping demand should step up to the ECO 27.