EcoSmart ECO 36
The EcoSmart ECO 36 is the top of the ECO electric line: 36 kW at 240 volts, aimed at whole-home service in homes without natural gas. Four self-modulating heating chambers ramp power to match demand, and a stainless-steel exchanger with digital control fills a compact 17 × 21 × 3.75 in cabinet — a fraction of a tank's footprint with no standby loss.
Thirty-six kilowatts is enough to be a serious whole-home heater: owners in warm and moderate climates run three-plus bathrooms, and even in a cold Northeast winter it holds around 3.5 GPM — enough for a shower plus a sink. But that power comes with the biggest electrical demand of any unit here: roughly 150 amps of draw, typically four double-pole breakers and, in some homes, a service upgrade just to accommodate it. That requirement — not the heater itself — is what stops many buyers. For an all-electric home that can feed it, the ECO 36 is the closest an electric tankless comes to gas-like whole-home performance.
Key Features
Best Use Cases
Our Verdict
The right electric tankless for a whole house without gas — provided your electrical service can handle ~150 A. It delivers genuine multi-bath flow in warm and moderate climates and a solid single-shower-plus in the cold. Price the possible panel or service upgrade into your decision; that, not the heater, is the real cost driver.
What owners report
Themes summarized from verified-purchase reviews across major retailers (4★ average, 1000 ratings). These are aggregated owner opinions — not our own bench testing.
Owners in warm and moderate climates report running multiple bathrooms, calling it the electric unit that finally delivers gas-like capacity.
The most repeated caution: ~150 A of draw means four breakers and, for some homes, a service upgrade before it can even be installed.
Reviewers in hard-water areas recommend periodic cleaning to prevent mineral buildup, though the stainless exchanger holds up well.
Most owners are satisfied, but a minority cite heating-element failures and slow customer service — keep proof of professional installation for the warranty.
EcoSmart ECO 36 FAQ
How much electrical service does the ECO 36 need?+
Roughly 150 A of draw at 240 V — commonly four double-pole breakers with four 8-gauge runs. Many homes need to confirm (or upgrade) their panel/service before installing it.
Will it work in a cold climate?+
Yes, within limits: it holds about 3.5 GPM at a 60–70 °F rise — a shower plus a sink in winter — and much more in warm-inlet conditions.
Is it cheaper to run than gas?+
Usually not. Electric resistance is ~99.8% efficient at the unit, but if you have natural gas, a condensing gas heater typically costs less per gallon depending on local rates.
Does hard water hurt it?+
The stainless exchanger tolerates hard water better than many, but owners in hard-water areas still recommend periodic cleaning to keep flow and temperature stable.
Price range from leading retailers
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