EcoSmart's Eco line is the brand's flagship whole-house electric tankless lineup. Models span ECO 11 (11 kW) through ECO 36 (36 kW), sized by climate and household demand. Eco units are flow-and-temperature self-modulating, meaning element power scales with actual demand rather than fixed staging.
Sizing the Eco line by climate
Electric tankless sizing depends on inlet water temperature and desired flow rate. A southern installation with 70°F inlet water needs less kW for same flow than a Maine installation with 40°F inlet. EcoSmart publishes sizing charts:
- ECO 11 (11 kW): 1.5–2.0 GPM in southern climates; suitable for studio or 1-bath apartment
- ECO 18 (18 kW): 2.5–3.5 GPM; 1–2 bath residence in mid-climate
- ECO 24 (24 kW): 3.5–4.5 GPM; typical 2–3 bath residence
- ECO 27 (27 kW): 4.0–5.0 GPM; larger residence or simultaneous shower + laundry
- ECO 36 (36 kW): 6.0+ GPM; heavy-demand or cold-climate whole-house
Self-modulating control
Eco units use flow sensors and inlet/outlet temperature sensors to determine real-time element power. At low flow, only one or two elements activate; at peak flow, all elements fire at full power. The control logic adjusts within milliseconds, delivering consistent outlet temperature regardless of how household demand changes.
Electrical service requirements
The biggest install constraint. ECO 27 at 27 kW requires three 40A double-pole circuits (240V) for 120A total. Verify your panel has spare capacity before purchasing. Service upgrades for whole-house tankless typically run $1,500–4,000 depending on existing panel size and main breaker. Many older 100A services cannot accommodate ECO 24 or larger without upgrade.
Eco vs Eco Plus differences
The Eco Plus variant adds a digital display showing flow rate, outlet temperature, and runtime statistics. Functionally, performance is identical to standard Eco — only the user interface changes. Plus models cost $50–100 more; worth it for monitoring high-demand installations.
Cold-water-sandwich management
Eco units, like all tankless, deliver a brief cold patch when hot draws stop and restart. Severity depends on pipe length between unit and fixture. For runs over 30 feet, consider: insulating pipes, installing a small mini-tank as a "buffer" at the fixture, or upgrading to a recirculation system.
Lifetime exchanger warranty
EcoSmart's lifetime exchanger warranty applies to the heating element assembly. Other components (control board, flow sensor, thermistors) carry shorter warranties (typically 1–5 years). The lifetime exchanger story is real but reads better than it operates — if a control board fails outside the 5-year warranty, that's a $200+ replacement that the exchanger warranty doesn't cover.
Installation by licensed electrician
Strongly recommended given the electrical service magnitude. Most jurisdictions require permitted installation with inspection for circuits this size. DIY installation is technically possible for someone with appropriate electrical expertise, but warranty support and code compliance both favor professional install.
Operating cost reality
Electric tankless saves vs electric tank water heaters mostly through elimination of standby loss. Vs gas tank, electric tankless costs more to operate in most US energy markets (electricity at $0.12+/kWh is more expensive per BTU than natural gas at $1.20/therm). The decision to install electric tankless usually reflects: no natural gas access, conversion to all-electric home, or rooftop solar offsetting electric demand.