EcoSmart ECO 11
Amazon customer rating as of
Tankless Geek editorial score: 4/5
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.
Technical Specifications
| Power | 13 kW @ 240 V |
|---|---|
| Electrical | One 60 A double-pole breaker · 6-gauge wire |
| Rated flow | Up to ~2.5–2.7 GPM (warm inlet) |
| Temp range | 80–140 °F, digital ±1° control |
| Dimensions | 18 × 8 × 3.75 in |
| Efficiency | 99.8% (electric resistance) |
Specifications verified against the linked source documents. See Sources below.
How much hot water you'll actually get
Usable flow drops as incoming water gets colder. Figures are calculated from rated output (kW) and labeled as such — not bench-tested by us.
| Temperature rise | Typical scenario | Usable flow |
|---|---|---|
| 35 °F | Warm climate (75 °F in → 110 °F) | 2.5 GPM |
| 45 °F | Mild climate (65 °F in → 110 °F) | 2 GPM |
| 60 °F | Cool climate (50 °F in → 110 °F) | 1.5 GPM |
| 70 °F | Cold climate (40 °F in → 110 °F) | 1.3 GPM |
Usable flow at a 110 °F target from EcoSmart's 13 kW output: kW × 3412 ÷ (ΔF × 500). Cold inlet water is exactly where a 13 kW unit runs out of headroom.
Pros
Cons
Buy it if…
- Single point of use — one bath, kitchen sink, or utility sink
- Warm-inlet regions where a ~2.5 GPM shower is realistic
- Additions, cabins, or RVs needing a compact heater
- Budget-focused buyers who can add a licensed 60 A circuit
Skip it if…
- Anyone wanting whole-home hot water in a cold climate
- Households running two fixtures at once
- Homes without room for a dedicated 60 A double-pole breaker
Installation Requirements
Professional vs DIY
A single-circuit unit like this is within reach of a confident DIYer with panel space, but have an electrician confirm the breaker/wire and pull any required permit.
Gas and electrical work should be done by a licensed professional, and most installs require a permit and must meet local building codes — DIY work can void the manufacturer warranty. Always confirm the unit's own manual for exact clearances, venting, and sizing.
What owners report
Themes summarized from retailer customer feedback (4.3/5 Amazon customer rating, 5599 ratings, as of 2026-09-06). These are 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.
Does the ECO 11 need maintenance in hard-water areas?+
Yes — like any tankless, mineral scale is its main enemy, and EcoSmart's warranty is conditional on meeting their water-quality requirements. In hard-water regions the heating chamber should be descaled periodically (flushed with a vinegar or descaling solution) to keep temperature stable and protect the elements; a whole-house softener or scale filter stretches the interval. Because the ECO 11 is small and wall-mounted with 1/2-inch connections, adding isolation service valves at install makes that flush quick — skip maintenance in hard water and you risk both performance and the warranty.
Product sources
Specifications verified 2026-09-06. Manufacturer documents are treated as the primary source for model specifications. Retailer pages are used only for customer ratings and owner-feedback themes.
- EcoSmart ECO 11 official product page (accessed 2026-09-06)
- Walmart / retailer owner reviews (accessed 2026-09-06)
- ConsumerAffairs — EcoSmart reviews (accessed 2026-09-06)
Price range from leading retailers
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