Compact electric tankless · ThermoMate

ThermoMate ET110 11 kW Electric Tankless Water Heater

11 kW compact electric tankless, about 46 A at 240 V

11 kW240 V~46 A2 Sets of Double-pole 30AMP Breakers2.7 GPM max~1.1 GPM at 70°F rise

Updated October 2026

The short answer

A practical compact electric tankless for light use in mild climates.

Delivers
11 kW.
Watch for
Winter flow is much lower.
Suits
Light use in mild climates.
Max flow (maker)
2.7 GPM
Power
11 kW
Voltage
240 V
Amps (maker)
46 A
Breakers (maker)
2 Sets of Double-pole 30AMP Breakers
Connections
1/2” npt
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What it delivers

The ThermoMate ET110 11 kW Electric Tankless Water Heater is a compact electric tankless rated at 11 kW on 240 volts. Its listing gives a maximum flow of 2.7 GPM.

Flow depends on how cold the incoming water is. Our estimate from its input: 1.7 GPM at a 45°F rise, falling to 1.1 GPM at 70°F, which is less than one 2 GPM shower on a cold-climate winter day. Size it to your fixtures.

At 240 volts 11 kW is about 46 amps (the listing states 46 A). The maker calls for 2 Sets of Double-pole 30AMP Breakers. Whether your panel can carry it alongside heating and cooking loads is an electrician's call.

No flue, no gas line and a compact box on the wall; the trade-off is that a cold winter inlet cuts its flow sharply.

Also on the listing: connections: 1/2” npt; material: Alloy Steel; model: ET110.

The listing gives dimensions of 11.75 in (W) x 14.75 in (H) and mounting kits in the box.

Right unit for this house?

Install it when

  • Light use in mild climates
  • Homes with no gas service

Look at another unit when

  • Panels without spare capacity
  • More than 1 shower at once in cold winters

Strengths and trade-offs

Strengths

  • 11 kW
  • Up to 2.7 GPM
  • No venting or gas line
  • Breakers stated by the maker

Trade-offs

  • Winter flow is much lower

Install limits

  • Figures are the maker's or seller's own. Flow at a rise is our estimate from the input; gas, venting and electrical work needs a licensed professional.

Rated performance

Every figure below comes from the source shown in brackets. Where the maker doesn't state something, we say so instead of estimating.

Model numberET110Retailer
Dimensions (seller)11.75"W x 14.75"HRetailer
Features (seller)Cast Aluminum Heating Chamber, Leakproof and maintenance free heating elementRetailer
Power11 kWRetailer
Voltage240 VRetailer
Max flow (maker)2.7 GPMRetailer
MaterialAlloy SteelRetailer
Amps (maker)46 ARetailer
Breakers (maker)2 Sets of Double-pole 30AMP BreakersRetailer
Connections1/2” nptRetailer

Rival units at this flow

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Final verdict

A practical compact electric tankless for light use in mild climates.

Buy this unit

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Prices change often; the button shows today's price.

Each button opens this exact model. We may earn a commission on tracked links; it never changes what we publish. Disclosure

Questions buyers ask

What breakers does the ThermoMate ET110 11 kW Electric Tankless Water Heater need?
About 46 amps at 240 volts (11 kW ÷ 240 V). The maker calls for 2 Sets of Double-pole 30AMP Breakers. Panel capacity, breakers and wire are confirmed by a licensed electrician from the manual.
How much hot water does the ThermoMate ET110 11 kW Electric Tankless Water Heater deliver in winter?
About 1.1 GPM at a 70°F rise and 1.7 GPM at a 45°F rise, estimated from its power and capped at its stated maximum.