Best Ecosmart US Tankless Water Heaters: 4 Models Compared

Quick picks

Our 4 picks

1 Best overall

EcoSmart ECOS 18 Electric Tankless

Best for: single bathroom or point-of-use installation

Fuel Type

Electric

Flow Rate

1.8 to 4.3 GPM

Wattage

18 kW

Voltage

240 V

Temperature Control

within 1 degree

Dimensions

19 x 4.25 x 9.25 inches

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The EcoSmart ECOS 18 is a compact electric tankless water heater designed for point-of-use applications. It delivers 1.8 to 4.3 gallons per minute at 18 kW and 240 volts. The unit maintains water temperature within 1 degree of your selection. Its small footprint allows for wall mounting or under-sink installation. This model suits single bathrooms or small sinks where space is limited.

Pros

• 18 kW power output for consistent hot water
• Flow rate of 1.8 to 4.3 GPM
• Temperature control within 1 degree
• Compact dimensions of 19 x 4.25 x 9.25 inches

Cons

• Lower 18 kW wattage compared to 27 kW models on this list
• Limited 1-year parts warranty
• Requires 240-volt electrical connection

Good fit if

• You need hot water for a single bathroom
• You want to install a heater under a small sink
• You prefer a compact unit for point-of-use heating

Skip if

• You need to supply hot water to multiple fixtures simultaneously
• You only have a 120-volt electrical outlet available
• You require a higher flow rate for a full household

Verdict: EcoSmart ECOS 18 18kW Electric Heater provides precise temperature control and compact sizing for single-fixture use. It fits best in small bathrooms or kitchens where space is tight and demand is low.

2 Best premium

EcoSmart 27 kW Electric Tankless Water Heater

Best for: single bathroom or point-of-use applications

Fuel Type

Electric

Flow Rate

2.7 to 6.6 GPM

Wattage

27 kW

Voltage

240 V

Temperature Control

within 1 degree

Dimensions

19 x 4.25 x 9.25 inches

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The Ecosmart ECOS 27 delivers 27 kW of power at 240 volts to heat water on demand. It provides a flow rate between 2.7 and 6.6 gallons per minute, depending on inlet temperature. This unit maintains temperature within 1 degree for consistent performance. Its compact 19 by 4.25 by 9.25 inch design saves space. It suits point-of-use applications like a bathroom or small sink where high flow is not critical.

Pros

• 27 kW heating capacity for reliable on-demand hot water
• 96% thermal energy efficiency reduces standby energy loss
• Precise temperature control within 1 degree of selected setting
• Compact dimensions of 19 by 4.25 by 9.25 inches

Cons

• Lower flow rate compared to higher wattage models
• Only 1 year parts warranty coverage
• Limited to point-of-use or low-flow applications

Good fit if

• You need a compact unit for a single bathroom
• You want precise temperature stability within 1 degree
• You prioritize energy efficiency over high flow volume

Skip if

• You require high flow rates for multiple fixtures
• You need a longer parts warranty than 1 year
• You are installing a whole-house water heating system

Verdict: Ecosmart ECOS 27 Electric Water Heater is a space-saving option for low-flow needs, offering precise temperature control but limited flow capacity compared to higher wattage models.

3 Best budget

Ecosmart US Performance 8 kW Electric Tankless Heater

Best for: single sink or small bathroom use

Fuel Type

Electric

Flow Rate

1.55 GPM

Wattage

8 kW

Dimensions

13.5 x 7 x 10 inches

Weight

7 pounds

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This Ecosmart US unit delivers 1.55 GPM at 8 kW. It measures 13.5 x 7 x 10 inches and weighs 7 pounds. The compact silver design fits tight spaces. It suits single-sink or small bathroom needs. You get self-modulating technology for efficient heating. It is a practical electric option for low-flow applications.

Pros

• 8 kW heating capacity
• 1.55 GPM flow rate
• Compact 13.5 x 7 x 10 inch size
• Lightweight 7 pound build

Cons

• Low 1.55 GPM flow rate limits simultaneous use
• 8 kW output is lower than 18 kW or 27 kW models
• Requires dedicated 240-volt circuit

Good fit if

• You need a heater for a single sink
• You have limited electrical panel capacity
• You want a compact unit for tight spaces

Skip if

• You need hot water for a full bathroom
• You require higher flow rates above 1.55 GPM
• You need higher wattage for multiple fixtures

Verdict: Ecosmart US 8 kW Electric Tankless Heater fits single-sink setups where space and electrical load are limited. It provides adequate hot water for one faucet but cannot support higher demand.

4 Best 5.0 gpm

Ecosmart US 18kW Electric Tankless

Best for: single bathroom electric installations

Fuel Type

Electric

Flow Rate

3.5 GPM

Wattage

18 kW

Dimensions

20 x 7 x 7 inches

Weight

11 pounds

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This electric tankless water heater delivers 18 kW of power with a flow rate of 3.5 GPM. It measures 20 x 7 x 7 inches and weighs 11 pounds. The unit is refurbished and certified to work like new. It suits you if you need a compact, self-modulating electric heater for a single bathroom or sink. The gray finish fits standard utility spaces.

Pros

• 18 kW heating capacity
• 3.5 GPM flow rate
• Compact 20 x 7 x 7 inch size
• Self-modulating technology

Cons

• Refurbished condition may show minor cosmetic wear
• Lower flow rate than 5.0 GPM competitors
• Electric model requires adequate electrical circuit capacity

Good fit if

• You need a compact electric heater for a single fixture
• You want a self-modulating unit to save energy
• You are comfortable with a refurbished product

Skip if

• You require a flow rate above 3.5 GPM
• You need a brand-new unit with original packaging
• You have a gas line available for a higher capacity heater

Verdict: Ecosmart US Performance 18kW 3.5 GPM fits you if you prioritize compact size and electric efficiency for a single bathroom. It offers reliable performance for low-to-medium flow needs.

Specifications side by side

Ecosmart US Models at a Glance

All listed units run on 240V electricity. This makes them suitable for indoor wall mounting where gas lines are unavailable. You can choose between 8 kW, 18 kW, or 27 kW power levels. Higher wattage generally supports higher flow rates for more demanding fixtures. The EcoSmart ECOS 18 offers a balanced 18 kW output for single bathrooms. The 27 kW model provides more power for similar applications.

Smaller units like the ECO 8 fit tight spaces under single sinks. The Performance 18kW model highlights a 5.0 GPM rating for stronger flow. Dimensions vary slightly, with widths from 7 to 9.25 inches. Weights range from 7 to 10.9 pounds. These compact designs allow flexible installation in cabinets or utility rooms. Select based on your specific hot water demand and electrical capacity.

Who Ecosmart US Fits Best

This brand suits renters or homeowners needing hot water for one fixture. The lineup ranges from the tiny 8 kW ECO 8 to the larger 27 kW ECOS 27. All units are compact, wall-mounted electric heaters. You get precise temperature control without the bulk of a tank. The range covers single sinks, small bathrooms, and point-of-use spots. Note that none of these models support whole-house demand or multiple simultaneous showers. If you need higher flow for a full home, this electric-only line may not meet your needs. Stick to these for low-flow applications.

How to choose the right one

1. Match wattage to fixtures

   Select the kilowatt rating based on how many faucets you need to run at once. The 8 kW ECO 8 handles a single sink well. If you need hot water for a small bathroom, the 18 kW ECOS 18 is a better fit. For slightly higher demand, the 27 kW ECOS 27 provides more power. Higher wattage means you can support more simultaneous use without temperature drops. Always check the kW spec before buying.

2. Check electrical voltage needs

   All Ecosmart US models in this list require a 240V electrical connection. This is standard for tankless electric heaters. You must ensure your home has the correct circuit capacity. Do not attempt to install these on standard 120V outlets. The voltage requirement is critical for safe operation. Verify your electrical panel can handle the amperage draw for your chosen wattage. This prevents tripped breakers and ensures proper heating performance in your bathroom or kitchen.

3. Measure available wall space

   These units are compact but still require specific dimensions for installation. The ECO 8 is the smallest, measuring 7 by 10 inches. The ECOS 18 and ECOS 27 are wider at 9.25 inches. Height varies slightly between 19 and 20 inches. Measure your intended mounting area carefully. Ensure you have enough clearance for connections and maintenance. Wall mounting is standard for these electric models. Proper spacing helps with airflow and future service access for your unit.

4. Consider flow rate demands

   Flow rate determines how much hot water you get per minute. The Performance 18KW model lists a 5.0 GPM rating. This supports steady flow for a single bathroom. Lower wattage models like the 8 kW unit have reduced flow capacity. If you need hot water for just one faucet, lower flow is acceptable. For showers, ensure the unit matches your showerhead flow requirements. Check the GPM spec to avoid cold water surprises during use.

5. Plan for installation location

   These electric heaters are designed for indoor wall mounting. They do not require gas lines or exterior venting. This makes them ideal for closets, under sinks, or utility rooms. Ensure the location is dry and accessible. The compact size allows for discreet placement in tight spaces. Verify that the electrical panel is nearby to reduce wire runs. Proper location planning simplifies installation and keeps the unit safe from moisture damage over time.

Frequently asked questions

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