Heater choices

3 Best Electric Tankless Water Heaters in 2026

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Our top 3 picks

1. 1Flow controlStiebel Eltron Tempra 29 PlusStiebel Eltron Tempra 29 Plus

   A home with enough electrical capacity that values a steady outlet temperature.

   • Electric heating: 28.8 kW at 240 V
   • Output falls to 21.6 kW at 208 V
   • Advanced Flow Control can reduce water flow

   Keep in mind: Holding temperature can mean a slower flow when demand exceeds output.

   View on AmazonRead our analysis
2. 2Electric alternativeRheem RTEX-24Rheem RTEX-24

   A home whose winter water load fits the model's flow table and whose power supply supports it.

   • Electric heating: 24 kW at 240 V
   • Digital temperature control
   • Heating elements replace a gas burner

   Keep in mind: The maximum stated flow does not guarantee the same flow from cold inlet water.

   View on AmazonRead our analysis
3. 3Controlled demandStiebel Eltron Tempra 24 TrendStiebel Eltron Tempra 24 Trend

   A measured hot-water load that stays within the unit's output.

   • Electric heating: 24 kW at 240 V
   • No combustion vent required
   • Trend controls differ from the Plus range

   Keep in mind: It does not include the Plus range's Advanced Flow Control.

   View on AmazonRead our analysis

The best electric tankless water heater must suit both the water load and the home's power supply. These three choices have different controls and outputs. Start with the coldest inlet water and the taps that run together. Then check the exact model's flow table and the power needed to run it. A small case does not mean a small electrical job.

#1. Stiebel Eltron Tempra 29 Plus: active flow control

Stiebel Eltron Tempra 29 Plus Stiebel Eltron Tempra 29 Plus

Our verdict:

Flow control

Households with sufficient electrical capacity that value a steady outlet temperature.

• Electric heating: 28.8 kW at 240 V
• Output falls to 21.6 kW at 208 V
• Advanced Flow Control can reduce water flow

Keep in mind: Holding temperature can mean a slower flow when demand exceeds output.

View on Amazon

Choose the Plus when steady outlet temperature matters and you accept that the flow can fall. Its Advanced Flow Control can reduce the water passing through the heater when demand is too high. That can keep a shower hot, but slower. It does not supply more heat than the unit can produce. Treat the change in flow as part of the choice.

The Tempra 29 Plus has a listed output of 28.8 kW at 240 V and 21.6 kW at 208 V. The lower voltage gives less heat. Do not use the higher figure for a home with the lower supply. Read the table for the actual voltage and the winter temperature rise. Both conditions affect the hot-water flow you can expect.

Plus and Trend are different control choices. Similar cases do not mean the same behavior at the limit. Our Tempra Plus review explains that trade-off in more detail. The Plus is worth comparing when the usual load fits, but occasional overlap might need flow control. It is a poor cure for a daily demand that is too large.

#2. Rheem RTEX-24: another electric range

Rheem RTEX-24 Rheem RTEX-24

Our verdict:

Electric alternative

A home with a supported electrical supply and an inlet temperature that suits the required flow.

• Electric heating: 24 kW at 240 V
• Digital temperature control
• Heating elements replace a gas burner

Keep in mind: The maximum stated flow does not guarantee the same flow from cold inlet water.

View on Amazon

The RTEX-24 offers a 24 kW electric option at 240 V with digital temperature control. Compare it using the same water conditions as the Tempra models. A dial sets a target. It does not establish that the heater can reach that target at any flow. The sizing table matters more than a picture of the controls.

This is a candidate where its supported flow meets the load and the electrical scope makes sense. Keep the full model name on the quote. Do not assume that an existing electric tank's circuit can run it. Ask for the required supply work as part of the proposal, before the equipment order becomes a reason to accept an expensive change.

Be careful with a maximum GPM figure. With warmer inlet water, the same heater can support more flow for a given outlet target. That number may describe a very different job from a winter shower. Ask which temperature rise supports the figure used in the quote. A number without its conditions is a weak basis for choosing between models.

#3. Stiebel Eltron Tempra 24 Trend: demand within output

Stiebel Eltron Tempra 24 Trend Stiebel Eltron Tempra 24 Trend

Our verdict:

Controlled demand

A modest, measured hot-water load that stays within the unit output.

• Electric heating: 24 kW at 240 V
• No combustion vent required
• Trend controls differ from the Plus range

Keep in mind: It does not include the Plus range's Advanced Flow Control.

View on Amazon

The Tempra 24 Trend is a 24 kW model at 240 V. It belongs on a shortlist for a known load that fits its table. The important difference from Plus is the lack of Advanced Flow Control. Do not choose by the Tempra name alone. Decide what happens when demand is high and whether your daily use stays within the supported flow.

For a household that can keep large draws apart, a smaller supported load may be enough. A bath can be filled while the shower is off. That is a real use pattern, but it must be acceptable to everyone using the home. Do not base the purchase on a schedule that is unlikely to be followed on a busy morning.

Higher output is useful only when it solves a measured need. It can also bring greater power requirements. If this model meets the winter load, ask what a larger model adds before paying for changes to the supply. If it does not meet the load, a different display or a similar cabinet will not fix the shortfall.

Factors to consider: best electric tankless water heater

Start with flow and temperature rise

List the taps that really run together. Measure their flow where useful. At a shower, total mixed flow and hot-water flow are not always the same. Keep those quantities clear when you record the demand. A bathroom count can help describe the home, but it does not replace the water load from actual fixtures.

Use a winter inlet condition. A summer water reading can make the output seem more generous than it will be in the cold months. Temperature rise is the gap from inlet to outlet. More rise needs more heat for each gallon. A heater can keep supplying a long draw only while that draw remains within its capacity.

Our electric sizing calculator estimates heat duty from flow and rise. It is a useful first screen. Take its inputs to the exact model's flow table and confirm the voltage. The calculator does not choose a brand or approve wiring. The main sizing tool also helps compare the water demand before you settle on electric heat.

Confirm the electrical work

Have a qualified electrician check the service and the loads already in the home. Empty breaker spaces do not prove enough spare power. A prior tank heater does not prove a suitable tankless circuit. The new model's manual governs its needs, and local code and the wiring route affect the installation. Get that scope before buying.

Do not turn one current estimate into a wire shopping list. Running current shows the scale of the demand. It does not settle the number of circuits or their protection. The electrical requirements guide explains the distinction. Ask the installer to name any service changes and keep unknown items visible in the quote.

Electric heat avoids a combustion flue. That helps when a gas vent route is awkward, but it does not make the project simple by default. Plumbing work still matters. So do safe access and the water supply.

Compare the full installed scope with other water-heating choices. A lower equipment price can be outweighed by the work needed to power it. Ask for the same scope in each quote, including removal of the old heater. If an item is excluded, keep it beside the quoted total rather than treating the omission as a saving.

Plan for care and daily use

Check the maker's water-quality limits. Use measured conditions to decide whether treatment is needed. A general filter does not necessarily remove hardness. Scale control and routine care should be planned for the actual water supplied to the home. Follow the exact model's manual rather than a generic procedure for another type of heater.

Leave space to reach the cover and the isolation points. Wall space saved is of little use if storage blocks every service visit. Keep the model details and manual where the next technician can find them. Ask who will provide service locally and read the warranty terms. Coverage length is not a prediction of how long the unit will last.

Think about a change in daily use too. A new shower head can raise flow, and a growing household may use more taps at once. Write down the load used to size the heater. Keep it with the quote so a future change can be checked against the same table. A model chosen for one shower at a time should not quietly become a plan for two.

Noise, looks and controls can help settle a choice only after the core checks pass. Start with enough heat and a safe supply. Then ask whether the controls are easy to use and the unit can be reached for care. This order keeps a neat display or a slim case from outweighing a limit that will affect every winter shower.

How We Picked

We used US manufacturer documents and exact catalog checks. These are published-data choices; we have not installed or tested the heaters. The comparison focuses on control behavior, supported output and the work required to supply power. Customer scores do not prove that a model fits your home. We do not use them as a substitute for sizing.

Verdict: best electric tankless water heater for your load

The best electric tankless water heater fits the home's supply as well as its water load. Choose Tempra Plus if active flow control is useful and its winter output fits. Compare RTEX-24 for the same demand, or Trend when the draw stays within its output. Confirm the home's capacity first. A larger electric model will not solve a supply problem.

Sources: Stiebel Eltron Tempra documents and Rheem tankless products. Product identity and published data checked October 16, 2026.

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Quick answers

What is the downside of an electric tankless water heater?

The electrical project can be a major part of the change. Check the exact model's circuits and the home's load capacity before ordering. A compact case and an existing electric tank circuit do not establish a supported tankless installation.

What is the most common issue with tankless water heaters?

The specifications used here do not establish which fault occurs most often. For selection, check winter output and the electrical supply, then plan water-quality care from the exact manual. Those checks are more useful than treating an unmeasured problem as a universal failure pattern.

Why don't plumbers like tankless water heaters?

There is no basis here to say plumbers share one view of tankless. A proposed electric installation still needs the water load and electrical work resolved together. Ask for the complete scope, including any required supply change, before choosing a heater.