The 5 tankless heaters we'd put in for the morning rushTop 5 tankless heaters → See the ranking
Compare models

Updated October 2026 · 5 heaters, no paid placements

Best Whole-House Electric Tankless Water Heaters in 2026

No gas line, no vent, just a lot of amps. These are the five whole-house electric units (240 V, 18 kW and up) we'd look at first, ranked on buyer ratings, review volume and specs, with the honest catch of each one. Talk to your electrician about the panel before you fall for one.

See the ranking

In short

Rheem 18 kW Electric, 240VOur top pickRheem 18 kW Electric, 240V9.3/10. The one we'd start with.$422.92 on Sep 30, 2026, may have changedStiebel Eltron Tempra 29 PlusThe crowd favouriteStiebel Eltron Tempra 29 Plus451 buyer reviews, 7.9/10. Plenty of owners to learn from.$798.99 on Sep 30, 2026, may have changedWINTEMP WN-36kW Electric, 240VThe most power on paperWINTEMP WN-36kW Electric, 240V36 kW per the listing, 8.1/10. The biggest figure among the rest.$499.98 on Sep 30, 2026, may have changed

Going electric? The Rheem 18 kW Electric, 240V is where we'd begin; the other four differ on kW, breakers and how many showers they can keep warm in January. Variants share a slot, which keeps five different electric units on this list.

Weighing gas against electric? The best whole-house tankless water heaters put both fuels side by side, and the best gas tankless water heaters cover natural gas and propane.

Written from each listing's specs and buyer reviews, not from our own use · How we rate

The ranking in detail

1Rheem 18 kW Electric, 240V
Electric tankless water heaters · Rheem · Top pick

Rheem 18 kW Electric, 240V

9.3Excellent · out of 10

Also available as: RTEX-24, 24 kW 240V

Best for: a smaller home or one main bathroom on electric

  • 18kW, 240V electric
  • Up to 4.4 GPM
  • Digital temperature display

The catch: Its 4.2/5 buyer rating sits under this list's 4.3 average.

4.2/5 from buyers2,187 buyer reviews$422.92 Price on Sep 30, 2026 · may have changed
See it on Amazon ↗ Rheem 18 kW Electric, 240V (opens in a new tab)Read the reviewaffiliate link to Amazon.com
2WINTEMP WN-36kW Electric, 240V
Electric tankless water heaters · WINTEMP · Runner-up

WINTEMP WN-36kW Electric, 240V

8.1Very good · out of 10

Also available as: WN-18kW Electric, 240V (18 kW)

Best for: two showers at once where gas is not an option

  • 36kW electric power
  • Self-modulating stable temperature
  • Compact wall-mounted design

The catch: It needs 1 × 50 A breakers, so price in the electrician.

4.4/5 from buyers203 buyer reviews, shared by 2 variants$499.98 Price on Sep 30, 2026 · may have changed
See it on Amazon ↗ WINTEMP WN-36kW Electric, 240V (opens in a new tab)Read the reviewaffiliate link to Amazon.com
3Stiebel Eltron Tempra 29 Plus
Electric tankless water heaters · Stiebel Eltron · Top 5 pick

Stiebel Eltron Tempra 29 Plus

7.9Very good · out of 10

Also available as: Tempra 24 Trend (24 kW) · Tempra 20 Trend (19.2 kW) · Tempra 29 Trend (28.8 kW) · Tempra 36 Trend (36 kW)

Best for: a home without gas and with a big panel

  • 28.8kW electric power
  • No venting required
  • Two temperature memory presets

The catch: The Stiebel Eltron listing doesn't say it self-modulates, unlike most of this list.

4.4/5 from buyers451 buyer reviews$798.99 Price on Sep 30, 2026 · may have changed
See it on Amazon ↗ Stiebel Eltron Tempra 29 Plus (opens in a new tab)Read the reviewaffiliate link to Amazon.com
4WINTEMP WM-36kW Plus Electric, 240V
Electric tankless water heaters · WINTEMP · Top 5 pick

WINTEMP WM-36kW Plus Electric, 240V

7.6Very good · out of 10

Also available as: WM-27kW Plus Electric, 240V (27 kW)

Best for: a whole house on electric in a warm or mild climate

  • 36kW electric power
  • WiFi app temperature control
  • Compact wall-mounted design

The catch: Only 60 buyer reviews so far, so that average can still move.

4.3/5 from buyers60 buyer reviews, shared by 2 variants$699.98 Price on Sep 30, 2026 · may have changed
See it on Amazon ↗ WINTEMP WM-36kW Plus Electric, 240V (opens in a new tab)Read the reviewaffiliate link to Amazon.com

Product images: Amazon listings

Best rated by stated heating power

The best-rated unit for each band of heating power its listing states. More kW means more hot water in winter, and more amps from your panel.

18 to 24 kWRheem 18 kW Electric, 240V (#1) · 9.3/10 · 18 kW
27 kW or moreWINTEMP WN-36kW Electric, 240V (#2) · 8.1/10 · 36 kW

How to choose

Electric tankless water heater pros and cons

The good: no vent, no gas line, no combustion air, and a box small enough to hang in a closet. That's why electric is the easy fit in an all-electric house.

The catch is current. A. O. Smith lists 51 A at 240 V for a 12.2 kW unit and up to 133 A for a 32 kW unit, and PNNL warns that instant electric heating creates high peak loads, which can cost more where your utility charges for peaks. Electric also makes less hot water than gas (the DOE Energy Saver page and A. O. Smith both say so), and that gap grows in winter. The gas vs electric guide compares the two on equal terms.

How many amps does each heater here need?

Plain arithmetic from the stated power: amps = watts ÷ volts. The exact breakers, wire sizes and number of circuits come from the manual and your electrician, never from this table.

Rheem 18 kW Electric, 240V18 kW stated · about 75 A at 240 V
WINTEMP WN-36kW Electric, 240V36 kW stated · about 150 A at 240 V
Stiebel Eltron Tempra 29 Plus28.8 kW stated · about 120 A at 240 V
WINTEMP WM-36kW Plus Electric, 240V36 kW stated · about 150 A at 240 V
APUS 27 kW Electric, 240V27 kW stated · about 112.5 A at 240 V

For scale: one shower at 2.0 GPM with 42 °F groundwater heated to 105 °F needs about 18.5 kW (GPM × rise × 500 ÷ 3,412). Two showers at once in a northern winter (about 36.9 kW) is beyond every unit here.

Smaller electric units: point of use and under the sink

Below 18 kW, most electric tankless heaters are point-of-use or small-household units: one sink, one shower in a mild climate, the far-off bathroom that takes forever to run hot. Our catalogue has 16 of them, one stating a 120 V supply. They stay out of this ranking, which starts at 18 kW, and none has a buyer review record yet; their pages rate them from the specs each listing states:

The point-of-use vs whole-house guide helps you tell which problem you have.

Comparison table

All 5 on one screen. Tap a column header to sort by what matters at 6:45 on a weekday: flow, power or price.

Comparison table: Best Whole-House Electric Tankless Water Heaters in 2026
Rheem 18 kW Electric, 240VRheem9.3$422.92†Electric4.4 GPM18 kW240 VNot stated2,187
WINTEMP WN-36kW Electric, 240VWINTEMP8.1$499.98†Electric8.7 GPM36 kW240 VNot stated203 (shared)*
Stiebel Eltron Tempra 29 PlusStiebel Eltron7.9$798.99†ElectricNot stated28.8 kW240 VNot stated451
WINTEMP WM-36kW Plus Electric, 240VWINTEMP7.6$699.98†Electric8.7 GPM36 kW240 VNot stated60 (shared)*
APUS 27 kW Electric, 240VAPUS7.4See current priceElectric6.5 GPM27 kW240 VNot stated120

† Prices as of Sep 30, 2026; they may have changed. The button always shows today's price.

* Shared: the same review pool appears on every variant of a listing family (WINTEMP, 2 variants), so the count is not specific to one variant.

How we rank

Every heater gets a score out of 10 from its exact listing. We look at what buyers give it, how many of them there are, and how completely the seller documents the specs and the warranty, then at how it stacks up against the other heaters in the list. On an exact tie, the listing slug settles the order.

We haven't installed or run these heaters ourselves, and a commission never moves a rating or a rank.

Read the methodology →Affiliate disclosure
  • 45 % buyer rating, damped when a listing has fewer than 50 reviews.
  • 35 % review volume, on a logarithmic scale up to 5,000 reviews.
  • 20 % documentation: feature bullets, images and stated brand of the listing.
  • Flow, BTU/h input, kW and voltage show up only when the exact listing states them. A headline GPM is not your winter flow, and we measure nothing ourselves.
  • One slot per listing family: variants of one parent listing, which usually share one review pool, count once and are listed under the best-rated variant.
  • Prices carry the date we recorded them. They may have changed since; the button shows today's offer.

Frequently asked questions

Which is the best whole-house electric tankless water heater in 2026?

Our pick is the Rheem 18 kW Electric, 240V, at 9.3/10 (excellent). It has 2,187 buyer reviews averaging 4.2/5, and its listing states 4.4 GPM and 18 kW. Next in line: the WINTEMP WN-36kW Electric, 240V at 8.1/10.

How is this ranking built?

We start from 25 complete electric tankless units whose exact listing states 240 V and at least 18 kW, each with a buyer review record. Each one gets a rating out of 10: 45 % buyer rating, 35 % review volume and 20 % how completely the listing documents its specs. Variants of one listing family (same parent listing) share a single slot, so you see 5 different heaters rather than one heater in 5 sizes.

What electrical service does a whole-house electric tankless heater need?

Every listing in this ranking states 240 V, with heating power from 18 kW to 36 kW. At 240 V each kilowatt draws about 4.2 A, so an 18 kW unit pulls about 75 A and a 36 kW unit about 150 A, usually spread over several dedicated circuits. Only a licensed electrician can tell you whether your panel and service can carry that, so ask before you order.

Will an electric tankless heater keep up in winter?

It slows down. The same power has to lift colder water further, so the flow at shower temperature drops in January. Check the maker's chart of flow against temperature rise, and size for your winter inlet temperature with our flow-rate calculator.

Are electric tankless water heaters worth it?

In an all-electric house with a panel that can carry them, often yes: no vent, no gas line, a small box. In a cold-water northern house with two showers running at once, one electric unit struggles, because one 2.0 GPM winter shower already takes about 18.5 kW. Size it from your rise first.

What size electric tankless water heater do I need for a whole house?

Work out the flow that runs together and your winter rise, then the kW: GPM × rise × 500 ÷ 3,412. One shower at 2.0 GPM with 42 °F water heated to 105 °F is about 18.5 kW; with warmer 62 °F groundwater the same shower needs about 12.6 kW. The flow-rate calculator does it for your fixtures.

Can an electric tankless water heater run on 120 V?

Not the ones in this ranking: every listing here states 240 V. The 120 V units in our catalogue are point-of-use models of 3.5 kW, listed in the section above.

Are the prices up to date?

Each price is the one we recorded on Sep 30, 2026, and it may have changed since. The button always opens the exact listing with today's price and seller.

Have you installed these water heaters yourselves?

No, we haven't installed them in a house of our own. The ratings come from what buyers say and from the specs stated in each exact listing, weighed with a formula we publish.

Tankless flow-rate calculator →Buying guide: how to choose a tankless water heater →Best Tankless Water Heaters in 2026 →Best Outdoor Propane Tankless Water Heaters in 2026 →Best High-Efficiency Condensing Tankless Water Heaters in 2026 →Best Gas Tankless Water Heaters in 2026 →Best Whole-House Tankless Water Heaters in 2026: Gas and Electric →All rankings →Comparison tool →
Electric tankless water heaters →Rheem →Stiebel Eltron →APUS →WINTEMP →Buying guides →