EcoSmart ECO 11
The EcoSmart ECO 11 is a 13 kW, 240-volt point-of-use electric tankless heater built around EcoSmart's patented self-modulating design — it draws only the power the current flow and temperature actually demand, rather than firing at a fixed wattage. At barely the size of a large book (18 × 8 × 3.75 in) it mounts almost anywhere and skips the standby losses and venting of a tank.
What it is not is a whole-home heater. Thirteen kilowatts is enough for a single fixture — one shower, a kitchen sink, or a bathroom group — and only holds a real shower flow when the incoming water is already fairly warm. In warm-inlet regions it comfortably runs ~2.5 GPM; in a northern winter, output falls toward a trickle, which is the single most common source of disappointed reviews. Matched to its job (one point of use, warm climate, or a booster) it is one of the least expensive ways to get endless hot water. Sized as a house's only heater in a cold state, it will frustrate.
Key Features
Best Use Cases
Our Verdict
A genuinely good point-of-use heater at a low price — as long as you respect the 13 kW ceiling. Buy it for a single fixture, an addition, an RV/cabin, or a warm-climate small home. Do not buy it as the sole heater for a multi-bath house in a cold region: the physics of 13 kW won't stretch that far no matter what the marketing implies.
What owners report
Themes summarized from verified-purchase reviews across major retailers (4.3★ average, 5599 ratings). These are aggregated owner opinions — not our own bench testing.
Owners using it for a single sink or shower consistently report endless hot water and a tiny footprint for the price.
The most common complaint: during winter cold spells the ECO 11 can only manage lukewarm showers, because 13 kW can't raise very cold inlet water fast at shower flow.
Reviewers note hot-cold swings when flow drops or under voltage sag — typical behavior for a small self-modulating electric unit.
A minority report the unit failing after roughly a year, a reminder to keep proof of professional installation for the warranty.
EcoSmart ECO 11 FAQ
Can the ECO 11 run a whole house?+
Only a very small, warm-climate one, or a single fixture. At 13 kW it holds about 2.5 GPM with warm inlet water and far less in winter — enough for one shower or sink at a time, not simultaneous fixtures.
What breaker and wire does it need?+
One 60 A double-pole breaker on 6-gauge wire, on a dedicated 240 V circuit. Have a licensed electrician confirm your panel has the capacity.
Why does it feel weaker in winter?+
Colder inlet water needs more energy per gallon. As the temperature rise you need climbs, the gallons-per-minute the unit can deliver falls — so the same heater feels strong in summer and weak in January.
Is the lifetime warranty really lifetime?+
It's a limited lifetime warranty on the exchanger and electronics for residential use, but it's conditional — keep proof of professional installation and follow EcoSmart's water-quality requirements.
Price range from leading retailers
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