What electrical circuit does an 18kW tankless heater need?

An 18kW unit draws about 75 amps at 240V, so it needs a dedicated high-amperage circuit and heavy gauge wiring. Installation should be done by a licensed electrician.

Can it run a whole house?

It suits one shower or a few fixtures in mild inlet water. In cold climates or with multiple hot taps running, output falls short of a whole-home demand.

Does it work with a standard shower?

Yes, it supplies hot water to a shower, sink, or salon station. Flow rate and incoming water temperature determine how hot the outlet stays.

Is it safe and certified?

It is ETL listed, which means it has been tested to North American electrical safety standards.

Does it need a tank or venting?

No tank and no gas venting. It mounts on the wall and connects directly to the water line and electrical supply.

18kW Instant Electric Tankless Water Heater

Best price now

$304.90at WayfairChecked Nov 9

Prices are checked against each store and labelled with when.

Visit Wayfair

18kW Instant Electric Tankless Water Heater

Best price now

$304.90at WayfairChecked Nov 9

Prices are checked against each store and labelled with when.

Visit Wayfair

Ask our agent about this product

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Price facts

Last seen at $304.90 at Wayfair on Nov 9.

Our take on the 18kW Instant Electric Tankless Water Heater

This is an 18kW electric tankless water heater that heats water on demand instead of storing it in a tank. The 18kW element is a high draw for a whole-home unit, so it needs a dedicated high-amperage circuit and is best treated as a point-of-use or small-home heater. A digital display lets you set and read the outlet temperature, and it is ETL listed. Compared with tank heaters it frees floor space and avoids standby losses, but it cannot serve multiple hot taps at once the way a larger gas or higher-output electric unit can.

Best forPoint-of-use hot water at one shower or sinkSmall homes and cabins with limited spaceSalons and shampoo stationsKitchen or bathroom retrofits without a tank

Pros

Heats water on demand, no storage tank
Digital temperature display for setting outlet heat
Compact wall-mounted unit frees floor space
ETL listed
No standby heat loss from a tank

Cons

18kW needs a heavy dedicated circuit and professional wiring
Output drops when flow rate rises or inlet water is cold
One unit struggles to feed several hot taps at once
Electric resistance heating can cost more to run than gas in many areas

18kW Instant Electric Tankless Water Heater prices at every store

WayfairNew
In stock
$304.90Checked Nov 9
Visit Wayfair

18kW Instant Electric Tankless Water Heater price history

Lowest price we've seen: $304.90 on Nov 9 at Wayfair. Tracked across 1 store since Nov 9.

From Wayfair

18kW instant electric tankless water boiler
Digital temperature display
Easy installation
24-hour water supply
For kitchen, bathroom, shower, mall, salon and shampoo use
ETL listed

Shipping: Free fast delivery; get it by Sun, Nov 15

About the 18kW Instant Electric Tankless Water Heater

This is an 18kW electric tankless water heater that heats water as it is used. It runs on electricity and is designed to provide a 24-hour water supply.

A digital display shows the water temperature. The unit is designed for easy installation and is ETL listed.

It can be used for a kitchen, bathroom, shower, mall, salon or shampoo station.

Power: 18kW
Power source: Electric
Type: Instant electric tankless
Display: Digital temperature display
Certification: ETL listed
Water supply: 24-hour
Use: Kitchen, bathroom, shower, mall, salon, shampoo

Specifications

Power Source: Electric

Questions and answers

What electrical circuit does an 18kW tankless heater need?: An 18kW unit draws about 75 amps at 240V, so it needs a dedicated high-amperage circuit and heavy gauge wiring. Installation should be done by a licensed electrician.
Can it run a whole house?: It suits one shower or a few fixtures in mild inlet water. In cold climates or with multiple hot taps running, output falls short of a whole-home demand.
Does it work with a standard shower?: Yes, it supplies hot water to a shower, sink, or salon station. Flow rate and incoming water temperature determine how hot the outlet stays.
Is it safe and certified?: It is ETL listed, which means it has been tested to North American electrical safety standards.
Does it need a tank or venting?: No tank and no gas venting. It mounts on the wall and connects directly to the water line and electrical supply.
Where is the 18kW Instant Electric Tankless Water Heater cheapest?: At Wayfair, for $304.90, as of our latest check.