EcoSmart ECO 36 Tankless Electric Water Heater, 36kW
The ECO 36 promises whole-house electric coverage but demands 150A of dedicated service -- more electrical capacity than many homes have available in total.
Updated
- Mixed-to-solid feedback from Amazon buyers
- 36kW at 240V requires 150A dedicated service -- unrealistic for most homes
- 8 GPM flow rate is only achievable with electrical infrastructure most homes cannot provide
- The Stiebel Eltron Tempra 20 Plus delivers comparable real-world output at 80A
Best For / Not For
Best for
- New construction with 400A service and planned dedicated capacity for electric water heating
- Commercial or multi-family applications with engineered electrical infrastructure
Not for
- Existing homes on 200A service -- 150A dedicated for water heating leaves almost no margin for other loads
- Buyers who assume they can add this to their existing panel without an electrician assessment
- Most residential whole-house applications where the Stiebel Eltron Tempra delivers equivalent output with half the electrical demand
Key Details
The Electrical Math Most Buyers Miss
A standard US home has 200A of total electrical service. Major loads in a typical home include an air conditioner at 30-50A, an electric range at 50A, an electric dryer at 30A, and various 15-20A circuits throughout. After those loads, a 200A panel commonly has 30-60A of remaining headroom. Adding 150A of dedicated water heater service to that equation is not a circuit addition -- it requires a service entrance upgrade to 400A, which means replacing the meter, the service entrance conductors, and the main panel.
EcoSmart is not being deceptive -- the specs are published -- but the product is designed for electrical environments most homeowners do not have. Check your service size and panel headroom with an electrician before purchasing, not after.
Why the Stiebel Eltron Is the Better Choice
The Stiebel Eltron Tempra 20 Plus achieves 3.5-4 GPM in moderate climates at 19.2kW, requiring an 80A circuit. For most households -- a shower, a sink, a dishwasher running in sequence rather than simultaneously -- this covers daily hot water demand without a panel upgrade. The ECO 36's advantage over the Tempra 20 is higher simultaneous flow capacity, but that only matters if your household consistently needs multiple high-flow fixtures running at the same time and you have the electrical service to support it.
If you genuinely need 8 GPM of electric output simultaneously, you need 400A service or a gas heater. If your realistic daily usage is 2-4 fixtures at moderate overlap, the Tempra 20 Plus covers it at 80A with strong buyer feedback. The ECO 36 targets a need that most residential buyers do not actually have at an electrical cost that makes gas alternatives competitive on total system cost.
Pros and Cons
Pros
- 36kW output can deliver high GPM if electrical infrastructure is available
- Self-modulating technology reduces power draw at lower demand
- Compact unit size for 36kW output
Cons
- 150A dedicated service requirement exceeds available capacity in most existing homes
- Mixed-to-solid buyer feedback, weaker than the Stiebel Eltron Tempra 20 Plus
- Installation costs can exceed the unit price once a panel or service upgrade is factored in
- Better-designed alternatives achieve comparable household output at half the electrical demand
Bottom Line
EcoSmart ECO 36 is a Skip. The 150A electrical service requirement makes it impractical for most existing homes without significant infrastructure upgrades that can cost more than the heater itself. The Stiebel Eltron Tempra 20 Plus delivers equivalent real-world household output at half the electrical demand, with stronger buyer feedback.
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