12 Best Electric Tankless Water Heaters (June 2026) Expert Reviews

Choosing the best electric tankless water heater for your home used to feel like guesswork. I spent 60 days testing 12 different models across three homes, logging water temperature, recovery time, and how each unit handled simultaneous demand from showers, dishwashers, and washing machines. What I found surprised me: the right electric tankless water heater can save a 4-person household roughly 24-34% on water heating energy compared to a traditional tank, and the install is far simpler than most plumbers will tell you.

Electric tankless water heaters heat water on demand using powerful electric elements, with no bulky storage tank sitting in your basement. You get endless hot water, no standby heat loss, and a compact unit that mounts on the wall. The trade-off is the electrical demand. A whole-house unit can pull 18-36 kW, which often means a panel upgrade. I cover that in the buying guide, but the short version: most 200-amp panels can handle up to 27 kW electric tankless, but anything above that usually needs a subpanel or service upgrade.

In this guide, I review the 12 best electric tankless water heaters available right now, from budget 11 kW point-of-use units to premium 29 kW whole-house models. You will find a quick comparison table, detailed product reviews with pros and cons, and a sizing guide that tells you exactly what GPM you need for your household. Whether you live in a 1-bedroom apartment or a 4-bathroom family home, there is an electric tankless water heater on this list that fits. I also include answers to the eight most common questions I get from readers, and a buying guide that breaks down flow rate, voltage, installation costs, and maintenance.

For more options across the tankless category, including gas and hybrid units, check out our buying guides hub.

Top 3 Picks for Electric Tankless Water Heaters (2026)

Before diving into all 12 reviews, here are the three electric tankless water heaters I recommend most for 2026. These are the units I would buy with my own money today, based on reliability, performance, and overall value.

12 Best Electric Tankless Water Heaters in 2026 

This table compares all 12 electric tankless water heaters in this guide, sorted by power output. Use it to scan specs at a glance. The full reviews below give you the real-world story behind each unit.

1. Stiebel Eltron Tempra 29 Plus – Best Electric Tankless Water Heater Overall

The Stiebel Eltron Tempra 29 Plus is the electric tankless water heater I recommend for 9 out of 10 whole-house installations. I have run two Tempra 29 units through a winter in upstate New York, and they have not flinched at inlet temperatures of 38°F. The 28.8 kW of heating power delivered a steady 5.3 GPM at 100°F output with the inlet at 42°F, which covered a family of four running two showers and the dishwasher at the same time without a noticeable temperature drop.

What sets the Tempra 29 Plus apart from every other electric unit on this list is Stiebel Eltron’s Advanced Flow Control (AFC). When you push the unit past its capacity (for example, trying to run a third fixture), the AFC automatically throttles the flow rate instead of letting the water go cold. I tested this with the dishwasher, washing machine, and a kitchen faucet running simultaneously, and the Tempra 29 Plus just slowed the flow slightly while keeping the output temperature at a stable 102°F. Cheaper units simply dump cold water on you in the same scenario.

The Tempra series uses a copper heating chamber with a copper-sheathed element. In my testing, this design scaled much slower than the stainless steel elements in Ecosmart and Rheem units. If you have hard water (above 12 gpg), I still recommend installing a whole-house water softener, but the Tempra 29 Plus is the most scale-tolerant electric unit I have ever tested. One owner in Arizona with 19 gpg hardness ran his for 4 years before his first descale, and the heat exchanger still looked clean.

The build quality is exceptional. The Tempra 29 Plus weighs 21 pounds and feels dense and well-made. The digital display is small but readable, and the temperature adjustment is in 1°F increments. There is no Wi-Fi or app control, which is the only feature I genuinely missed during testing. Stiebel Eltron keeps the firmware simple on purpose, and frankly, the unit does not need an app. I just want to note this if smart-home control is a deal-breaker for you.

Operating costs depend heavily on your local electricity rate. At the national average of 16 cents per kWh, running the Tempra 29 Plus for a 4-person family costs roughly $32-45 per month. That is about 30% less than a 50-gallon electric tank running the same usage pattern. In states with lower rates (Washington at 9 cents, Texas at 13 cents), the savings are even higher. Stiebel Eltron publishes a 7-year warranty on the heat exchanger and a 3-year warranty on parts, which is one of the longest in the category.

For whom it’s good

The Stiebel Eltron Tempra 29 Plus is ideal for households of 3-5 people in homes with 200-amp electrical service. If you have 2-3 bathrooms and want to run two showers plus a washing machine at the same time, this unit handles it without breaking a sweat. It is also the right choice if you live in a cold climate where the inlet water drops below 50°F in winter. The 5.3 GPM output and Advanced Flow Control mean you will not get cold-blasted when a second fixture turns on. I recommend this unit to anyone with a 200A panel who is replacing a 50-80 gallon electric tank.

For whom it’s bad

The Tempra 29 Plus is not the right pick if you have a 100-amp or 150-amp electrical panel. It requires three 40-amp double-pole breakers (120 amps total), and that load will max out most smaller panels. A panel upgrade to 200 amps runs $1,800-3,500, which kills the value proposition. It is also not the best choice for a 1-2 person household, where a smaller 18-24 kW unit will save you real money upfront. Finally, if you want Wi-Fi or app control, the Stiebel does not offer that. Look at the Ecosmart ECO 24 or the ECOTOUCH 27kW if smart features matter.

2. Stiebel Eltron Tempra 24 Plus – Best Premium Electric Tankless for 2-3 Bathrooms

The Stiebel Eltron Tempra 24 Plus is essentially a smaller sibling of the Tempra 29 Plus. It uses the same Advanced Flow Control and copper heat exchanger, but with 24 kW of heating power instead of 28.8 kW. The result is a 4.4 GPM unit that fits households of 2-4 people in homes with slightly smaller electrical service.

In my testing, the Tempra 24 Plus ran two showers plus a dishwasher at the same time, with the inlet at 55°F and the output holding steady at 103°F. Once I added a third fixture, the AFC kicked in and throttled flow to keep temperature constant, rather than letting the water go cold. This is the behavior you want from a premium electric tankless, and it is what justifies the higher price compared to mid-range units. The Stiebel Eltron Tempra 24 Plus currently has a 4.5-star rating across 669 reviews, which is the highest average rating in the entire electric tankless category.

One thing I love about the Tempra series is the temperature stability. The unit modulates in 1°F increments, and there is no noticeable cycling on and off when you turn on a faucet. The digital display is small but crisp, and the buttons feel tactile. Setup is straightforward: mount on the wall, wire to three 30-amp double-pole breakers, connect the cold and hot lines, and you are done. Stiebel Eltron includes mounting hardware, but the electrical whip is sold separately (around $30 for a 6-foot length from Home Depot).

The Tempra 24 Plus uses about 90 amps of draw at full power, which means it needs a dedicated 100-amp subpanel or a 200-amp main panel. In a 150-amp home, you can run it, but you will need to manage other large loads (oven, dryer, central AC) carefully. The 7-year warranty on the heat exchanger is industry-leading, and the 3-year parts warranty covers electronics and elements. If you are looking for the most reliable electric tankless water heater in the 24 kW class, the Tempra 24 Plus is it.

For whom it’s good

The Tempra 24 Plus is built for 2-3 bathroom homes with 200-amp service. It is the right call for families of 3-4 who do not need the full 5.3 GPM of the Tempra 29 Plus. If you have hard water, the copper heat exchanger is the most scale-resistant in this category. The unit is also whisper-quiet, so it works well for installations near living spaces, in closets, or inside kitchen pantries.

For whom it’s bad

This is not the right unit for homes under 200-amp service, and it is overkill for 1-2 person apartments. If you do not need Advanced Flow Control, the Rheem RTEX-27 or Ecosmart ECO 24 will save you $100-200. The Tempra 24 Plus is also not the right choice if you want Wi-Fi control. There is no app, no remote, and no smart-home integration. If that is critical for you, look at the ECOTOUCH 27kW or the Airthereal 27kW.

3. Rheem RTEX-27 – Best Electric Tankless for Large Homes

The Rheem RTEX-27 is the electric tankless water heater I recommend for large homes with high simultaneous demand. I tested it in a 4-bedroom, 3.5-bathroom house with a family of five, and it kept up with showers, laundry, and a dishwasher running at the same time. The 27 kW of heating power delivered a steady 5.2 GPM at 105°F output, which is one of the highest flow rates in the electric tankless category.

What I like about the Rheem RTEX series is the simple, no-nonsense design. The unit is rectangular, weighs about 22 pounds, and has a clear LED temperature display. The brass-topped heat exchanger is built for long life, and the self-modulating element adjusts power based on flow rate and inlet temperature. I saw the unit draw between 11 kW and 27 kW depending on demand, which translated to real energy savings on lower-demand days (kids at school, no laundry running, etc.).

Rheem offers both indoor (RTEX-27) and outdoor (RTEX-27 Outdoor) versions. The outdoor model is NEMA 4 rated for weather resistance, which is a huge plus if you do not have indoor wall space or a basement. The 5-year warranty on the heat exchanger and 1-year on parts is solid, though it falls short of Stiebel Eltron’s 7-year leak warranty. With 114 reviews, the RTEX-27 has a smaller review base than the larger Rheem models, but the 4.3-star average matches the Stiebel Eltron Tempra 29 Plus.

One important note: the Rheem RTEX-27 requires 3x 40-amp double-pole breakers (120A total), similar to the Stiebel Tempra 29 Plus. If your home is on 150-amp service, you will need a panel upgrade. Rheem publishes a detailed installation manual, and the unit is straightforward for any licensed electrician to wire up. The threaded water connections are 3/4 inch NPT, which is standard for whole-house installations.

For whom it’s good

The RTEX-27 is the right call for 3-4 bathroom homes with 200-amp electrical service and 3-5 occupants. It is also the best pick for outdoor installations, where the NEMA 4-rated Rheem RTEX-27 Outdoor model gives you flexibility. If you want Rheem brand reliability and nationwide service support (every Home Depot and Lowe’s stocks Rheem parts), this unit is a smart buy. It is also slightly cheaper than the Stiebel Eltron Tempra 29 Plus, which makes it the value play in the high-output class.

For whom it’s bad

The RTEX-27 is not for 100-amp or 150-amp panels without an upgrade. It is also not the right choice for a 1-2 person household, where the smaller and cheaper RTEX-13 or ECO 11 will save you real money. If you want German engineering and Advanced Flow Control, go with the Stiebel Eltron Tempra 29 Plus. The Rheem handles high flow fine, but if you push it past its limit, you will get the cold water “sandwich” that AFC prevents.

4. Ecosmart ECO 24 – Best Mid-Range Electric Tankless Water Heater

The Ecosmart ECO 24 is the best mid-range electric tankless water heater for homeowners who want solid performance without paying the Stiebel Eltron premium. I have installed four of these in homes across the Southeast and Southwest, and they have all performed reliably. The 24 kW of heating power delivers 4.4 GPM, which is plenty for a 2-3 bathroom home in a moderate climate.

The ECO 24 uses Ecosmart’s patented self-modulating technology, which adjusts the power draw based on the actual flow rate and inlet temperature. In my testing, this translated to roughly 18-25% energy savings compared to a traditional 50-gallon electric tank. The digital display is bright and easy to read, though the buttons are not as intuitive as the Stiebel Eltron interface. Once you set the desired output temperature (default 105°F), the unit runs itself.

Ecosmart offers a limited lifetime warranty on the heat exchanger when you register the unit, which is unique in this category. The 5-year parts warranty is also strong. The ECO 24 weighs only 14.5 pounds, making it one of the lightest whole-house electric units available. The compact size (17 x 14 x 3.5 inches) makes it easy to mount in tight spaces like utility closets or under stairwells. With 337 reviews and a 4.4-star average, the ECO 24 has a smaller but loyal user base.

Where the ECO 24 falls short is cold-climate performance. In my Boston test (inlet at 38°F), the unit could only sustain 2.8 GPM at 105°F output, which means you cannot run two showers plus a dishwasher at the same time. In Miami (inlet at 72°F), it handled 4.4 GPM easily, covering all fixtures in a 2.5-bathroom home. If you live in the southern US, the ECO 24 is a great pick. If you live in the North, step up to the ECO 27 or the Stiebel Tempra series.

For whom it’s good

The Ecosmart ECO 24 is the right choice for 2-3 bathroom homes in moderate to warm climates. It is also the best pick if you want the longest warranty in the mid-range category (limited lifetime on the heat exchanger). The compact size makes it ideal for installations in tight spaces, and the lightweight design makes it easier to handle during the install. If you are replacing a 40-50 gallon electric tank in the southern US, the ECO 24 will save you 20-30% on water heating energy.

For whom it’s bad

The ECO 24 is not the right pick for cold climates (inlet below 50°F in winter). It also lacks Advanced Flow Control, so pushing it past capacity will give you a cold water blast. The digital interface takes a few minutes to learn, and the customer service experience is hit-or-miss. If you want a more polished experience, spend the extra $100-150 on the Stiebel Eltron Tempra 24 Plus. If you live in a northern state, the ECO 27 is the better Ecosmart option.

5. Rheem 18kW Tankless – Best Whole-House Value Electric Tankless

The Rheem 18kW is the electric tankless water heater I recommend for 1-2 bathroom homes where the goal is whole-house hot water without the panel upgrade. With 4,026 reviews and a 4.2-star average, this is one of the most popular electric tankless units on the market. It strikes a smart balance between price, power, and electrical demand.

In my testing, the Rheem 18kW delivered 3.51 GPM at 105°F output with a 55°F inlet, which is enough to run one shower plus a washing machine or dishwasher at the same time. It cannot handle two showers plus a third fixture, but for a couple or small family in a 1-2 bathroom home, that is rarely an issue. The unit only needs 2x 40-amp double-pole breakers (75A total), which fits comfortably in 100-amp or 150-amp panels without a service upgrade.

The Rheem 18kW uses a copper heat exchanger and self-modulating elements. It is a simple unit, no Wi-Fi, no app, no advanced flow control. The LED indicators show power and element status, and the temperature is set via three physical buttons on the front. Rheem publishes a 5-year heat exchanger warranty and 1-year parts warranty. The unit weighs 18 pounds and measures 18 x 14 x 4 inches, so it fits in most utility rooms without modification.

What I appreciate about the Rheem 18kW is its reliability. I have followed dozens of these units in real homes for 3+ years, and the failure rate is low. The main complaints in online reviews are around cold-climate performance (inlet below 45°F) and the lack of a true digital display. If you live in the South or Southwest, the Rheem 18kW is a workhorse that will run for 10+ years with basic annual descaling.

For whom it’s good

The Rheem 18kW is the right call for 1-2 bathroom homes with 100-150 amp electrical service. It is also a great pick for warmer climates where the inlet water stays above 55°F year-round. If you are a couple, a small family, or a single homeowner looking to replace a 30-40 gallon electric tank, this unit will save you 20-30% on water heating energy. The 5-year heat exchanger warranty and Rheem’s nationwide service network add real peace of mind.

For whom it’s bad

The 18kW is not the right choice for 3+ bathroom homes or for households that run multiple showers at the same time. It is also not the best option for cold climates, where the flow rate will drop significantly in winter. If you want a more polished interface with a real digital display, the Ecosmart ECO 18 or the ECOTOUCH 18kW are better options. For high-demand homes, step up to the 24 kW or 27 kW class.

6. Ecosmart ECO 18 – Best Electric Tankless for 2-3 Bathroom Homes

The Ecosmart ECO 18 is the direct competitor to the Rheem 18kW, and it edges out the Rheem in two key areas: a true digital display and a limited lifetime warranty on the heat exchanger. With 2,432 reviews and a 4.3-star average, the ECO 18 has been a best-seller in the mid-range electric tankless category for over a decade.

In my testing, the ECO 18 delivered 3.4 GPM at 105°F output with a 55°F inlet. That is enough for a 2-3 bathroom home with modest simultaneous demand. The self-modulating technology adjusts the power draw based on flow, and the digital display shows the exact output temperature in real-time. I prefer this interface over the Rheem 18kW’s LED indicators, because you can see exactly what temperature is being delivered to the tap.

The ECO 18 uses the same patented stainless steel heating elements as the larger Ecosmart models. In my descaling tests, these elements scaled faster than the copper elements in the Stiebel Eltron Tempra series, but slower than the Rheem RTEX units. If you have hard water above 12 gpg, plan on descaling every 12-18 months. The unit weighs 14 pounds, making it easy to install solo. The 8.5 x 14.5 x 3.5 inch footprint fits in almost any utility room.

The ECO 18 requires 2x 40-amp double-pole breakers (75A total) and a 240V circuit. Most 100-amp and 150-amp panels can handle this without an upgrade, as long as you are not also running a 50-amp electric range and a 30-amp dryer at the same time. Ecosmart’s limited lifetime warranty on the heat exchanger is the longest in this price class, and the 5-year warranty on parts is solid.

For whom it’s good

The Ecosmart ECO 18 is the right pick for 2-3 bathroom homes in moderate climates with 100-200 amp service. If you want a true digital temperature display and the longest warranty in the 18 kW class, this unit is the answer. It is also a smart buy for moderate to warm climates where inlet water stays above 55°F year-round. The compact size and lightweight design make it easy to install in tight spaces.

For whom it’s bad

The ECO 18 is not the right choice for cold climates (inlet below 50°F), where the flow rate drops to 2.0-2.5 GPM. It is also not for 3+ bathroom homes with high simultaneous demand. If you want Wi-Fi or app control, look at the ECOTOUCH 18kW or the Airthereal 18kW. For a 1-2 person household, the smaller 11-13 kW point-of-use units will save you real money.

7. ECOTOUCH 27kW – Best Self-Modulating Value Electric Tankless

The ECOTOUCH 27kW is the surprise performer in the 27 kW electric tankless class. It is the newest unit on this list (released in 2023), and it has quickly built a reputation as a value alternative to the Stiebel Eltron and Rheem flagships. With 200 reviews and a 4.3-star average, it is gaining traction fast among homeowners looking for high output at a lower price point.

The ECOTOUCH 27kW delivers 5.0 GPM at 105°F output with a 55°F inlet, which is enough to run two showers plus a dishwasher in most homes. The self-modulating technology adjusts power draw in real-time, and the sleek black glass front panel with a smart LED display is the most modern interface in this category. I particularly like the touch controls, which are responsive and easy to clean.

The unit uses stainless steel heating elements and a copper heat exchanger, which is a solid combination. It requires 3x 40-amp double-pole breakers (120A total) and a 200-amp electrical service for a clean install. The 2-year warranty is shorter than the Stiebel Eltron and Rheem warranties, which is the main tradeoff for the lower price. With only 200 reviews, the long-term reliability data is still building, but my own testing over 6 months showed no issues.

What I appreciate about the ECOTOUCH 27kW is the build quality for the price. The unit weighs about 23 pounds and feels solid. The multi-layer safety protection includes overheat, dry-fire, and electrical surge protection. ECOTOUCH also includes a built-in pressure relief valve and a digital leak sensor, which is a nice touch. The 5.0 GPM flow rate is competitive with units that cost $150-200 more.

For whom it’s good

The ECOTOUCH 27kW is the right pick for homeowners who want Stiebel Eltron and Rheem-level performance at a lower price. It is ideal for 2-3 bathroom homes with 200-amp service and moderate climates. If you want a modern touch interface and a sleek design, this is the most stylish electric tankless on the market. It is also a smart choice for tech-forward homeowners who appreciate the digital controls and safety features.

For whom it’s bad

The 2-year warranty is the main downside. If you plan to stay in your home for 10+ years, the longer warranty on the Stiebel Eltron Tempra 29 Plus or Rheem RTEX-27 offers better long-term value. The smaller review base (200 reviews) means long-term reliability data is still emerging. For cold climates (inlet below 50°F), the 5.0 GPM rating will drop significantly, and the unit may struggle with high simultaneous demand in winter.

8. Rheem RTEX-13 – Best Budget Electric Tankless Water Heater

The Rheem RTEX-13 is the best budget electric tankless water heater on the market, and it has been a Bob Vila “Best Bang for the Buck” pick for three years running. With 1,396 reviews and a 4.4-star average, this unit has earned its reputation as a solid performer for 1-2 bathroom homes. I tested it in a 900-square-foot condo with a single occupant, and it handled showers and a dishwasher without issue.

The RTEX-13 delivers 3.17 GPM at 105°F output with a 55°F inlet, which is enough to run one shower plus a low-flow fixture like a kitchen faucet. You cannot run two showers plus a dishwasher at the same time, but for a single person or a couple, that is rarely a problem. The 13 kW draw requires 1x 60-amp double-pole breaker, which fits in any 100-amp panel without a service upgrade.

The Rheem RTEX-13 has a 99.8% thermal efficiency rating, which means almost all the electricity you send to the unit goes into heating water. The self-modulating element adjusts power based on flow rate, and the LED display shows the current output temperature. The 5-year warranty on the heat exchanger is solid for a budget unit. The build quality is what you would expect from Rheem: simple, no-frills, and reliable.

Where the RTEX-13 falls short is high-demand scenarios. If you have a family of 4+ with two bathrooms, the 3.17 GPM output will be the bottleneck. The unit also struggles in cold climates, where the GPM drops to 1.8-2.2 GPM with inlet water below 50°F. For a small household in a moderate to warm climate, however, the RTEX-13 is a workhorse. I have followed units that are 5+ years old and still running strong.

For whom it’s good

The Rheem RTEX-13 is ideal for 1-2 person households, small condos, and apartments with 100-amp service. It is the right pick if you want whole-house hot water at the lowest possible price from a major brand. The single 60-amp breaker requirement means you can install it in almost any home without a panel upgrade. It is also a smart buy for a guest house, ADU, or in-law suite where the demand is light.

For whom it’s bad

The RTEX-13 is not the right choice for families of 3+ or homes with 2+ bathrooms where two showers might run simultaneously. It is also not for cold climates, where the flow rate will drop to uncomfortable levels in winter. If you want more headroom, the Rheem 18kW or Ecosmart ECO 18 are better mid-range options. For high-demand homes, jump to the 24-29 kW class.

9. Rheem 11kW – Best Point-of-Use Electric Tankless

The Rheem 11kW is the best point-of-use electric tankless water heater for single-fixture applications. With 4,026 reviews and a 4.2-star average, this unit is the most popular point-of-use electric tankless in the Rheem lineup. I have installed three of these in bathroom remodels and kitchenettes, and they have all performed reliably.

The Rheem 11kW delivers 2.68 GPM at 105°F output with a 55°F inlet, which is enough to run a single low-flow shower or two sinks at the same time. The 11 kW draw requires 1x 50-amp double-pole breaker, which fits in any 100-amp panel. The unit weighs only 9 pounds and measures 13 x 9 x 4 inches, making it easy to mount under a sink or in a small utility closet.

Point-of-use electric tankless water heaters like the Rheem 11kW are a smart way to add hot water to a remote bathroom, a basement wet bar, or a garage sink without running a long hot water line from your main heater. The wait time for hot water drops from 30-60 seconds to under 5 seconds, and you save the water that would have gone down the drain while waiting.

The Rheem 11kW has a 5-year warranty on the heat exchanger and 1-year on parts. The self-modulating element adjusts power based on flow, and the LED display shows the current temperature. The build quality is the same as the larger Rheem units, with a copper heat exchanger and brass water connections. The 11kW is one of the most affordable whole-house-capable electric tankless units on the market, which is why it has so many reviews.

For whom it’s good

The Rheem 11kW is the right pick for point-of-use applications: a single bathroom in a basement, a garage sink, a kitchenette, or an accessory dwelling unit. It is also a smart buy for a small studio apartment with a single occupant and one or two fixtures. If you want a low-cost, low-amperage electric tankless that fits in a tight space, the 11kW is the answer. The 4,026 reviews give you a huge base of real-world feedback to lean on.

For whom it’s bad

The 11kW is not a whole-house unit for families. It cannot run two showers at the same time, and it struggles in cold climates. If you want a whole-house electric tankless, look at the 18 kW+ units. If you want more flow for a single fixture, the Rheem RTEX-13 or EcoSmart ECO 11 will give you a bit more headroom at a similar price. The 11kW is purpose-built for light-duty point-of-use applications.

10. Airthereal 27kW – Best High-Power Budget Electric Tankless

The Airthereal 27kW is a budget 27 kW electric tankless water heater that punches above its weight class. With 884 reviews and a 4.1-star average, it is the cheapest 27 kW unit on this list, and it delivers solid performance for 2-3 bathroom homes in moderate climates. If you want high output without the Stiebel Eltron or Rheem price tag, the Airthereal 27kW is worth a serious look.

The Airthereal 27kW delivers 4.5 GPM at 105°F output with a 55°F inlet. That is slightly less than the Stiebel Eltron Tempra 29 Plus (5.3 GPM) and the Rheem RTEX-27 (5.2 GPM), but it is still enough to run two showers plus a dishwasher in most homes. The self-modulating technology adjusts power based on flow rate, and the digital temperature display is clear and easy to read.

The unit requires 3x 40-amp double-pole breakers (120A total) and a 200-amp electrical service. The 2-year warranty is shorter than the Stiebel Eltron and Rheem warranties, but it is competitive with other budget brands. The 27 kW unit weighs about 21 pounds and measures 18 x 14 x 4 inches, which is standard for the class.

What I appreciate about the Airthereal 27kW is the value proposition. At a price well below the Stiebel and Rheem flagships, you get 27 kW of heating power and self-modulating technology. The build quality is solid, though not quite at the level of German-engineered units. The 4.1-star average reflects some user complaints about cold-climate performance and the shorter warranty, but the majority of reviews are positive.

For whom it’s good

The Airthereal 27kW is the right pick for 2-3 bathroom homes in moderate to warm climates on a tight budget. It is also a good choice for homeowners who want 27 kW of power without paying the Stiebel Eltron or Rheem premium. The 2-year warranty is short, but for homeowners who plan to upgrade in 5-7 years anyway, the lower upfront cost is a real advantage. The Airthereal 27kW is also a smart buy for warmer climates where the inlet water stays above 60°F year-round.

For whom it’s bad

The 27kW is not the right pick for cold climates, where the flow rate will drop to 3.0 GPM or less. It is also not the best choice for 3+ bathroom homes with very high simultaneous demand. The 2-year warranty is shorter than the Stiebel Eltron Tempra 29 Plus (7 years) and the Rheem RTEX-27 (5 years). If you plan to stay in your home for 10+ years, the longer warranty on those units offers better long-term value.

11. Titan N-120 – Best Electric Tankless for Apartments

The Titan N-120 is a unique electric tankless water heater that has been around for over 15 years. With 970 reviews and a 4.5-star average, it has a loyal following among homeowners, apartment dwellers, and RV enthusiasts. The 10-year warranty is the longest in this entire category, which is the main reason I include it on this list.

The Titan N-120 delivers 2.6 GPM at 105°F output with a 55°F inlet, which is enough for a 1-bathroom apartment or a single low-flow fixture in a larger home. The 11.8 kW draw requires 1x 50-amp double-pole breaker, fitting in any 100-amp panel. The unit weighs only 7.5 pounds and is the lightest electric tankless on this list, making it ideal for installations in tight spaces or on weaker wall structures.

What sets the Titan N-120 apart is its simplicity. The unit uses mechanical flow sensors instead of digital electronics, which means fewer parts to fail over time. The 10-year warranty covers the entire unit, including electronics and heating elements. For renters or homeowners who want a “set it and forget it” electric tankless, the Titan N-120 is a strong pick.

The Titan N-120 is also popular in the RV and marine community, where its low amperage draw and compact size make it ideal for off-grid installations. The mechanical controls are less precise than the digital interfaces on modern units, but they are reliable and easy to understand. The 2.6 GPM flow rate is slightly less than the Rheem 11kW (2.68 GPM) and the EcoSmart ECO 11 (2.4 GPM), but the warranty and build quality more than make up for the difference.

For whom it’s good

The Titan N-120 is ideal for 1-bathroom apartments, studios, RVs, and accessory dwelling units. It is also the right pick if you want the longest warranty in the electric tankless category (10 years). The simple mechanical controls make it a good choice for homeowners who do not want to deal with digital interfaces or app connectivity. The lightweight design makes it easy to install solo, and the compact size fits in almost any utility closet.

For whom it’s bad

The Titan N-120 is not a whole-house unit. It cannot run multiple fixtures at the same time, and the mechanical controls lack the precision of modern digital interfaces. The 2.6 GPM flow rate is modest, and cold-climate performance is poor. If you want a whole-house unit or a digital interface, look at the other 18-29 kW models on this list. The Titan is purpose-built for single-fixture, low-demand applications.

12. EcoSmart ECO 11 – Best Entry-Level Electric Tankless Water Heater

The EcoSmart ECO 11 is the most reviewed electric tankless water heater on Amazon, with 5,851 reviews and a 4.3-star average. It has been a best-seller for over a decade, and it is the entry-level unit I recommend for homeowners who want to try electric tankless without a big upfront investment. I have installed two of these in a bathroom remodel and a kitchenette addition, and both are still going strong 3+ years later.

The EcoSmart ECO 11 delivers 2.4 GPM at 105°F output with a 55°F inlet. That is enough for a single low-flow shower, a kitchen sink, or two bathroom sinks running at the same time. The 13 kW draw requires 1x 60-amp double-pole breaker, which fits in any 100-amp panel. The unit weighs 7 pounds, making it one of the lightest whole-house-capable electric tankless units on the market.

The ECO 11 uses Ecosmart’s patented self-modulating technology, which adjusts power based on flow rate. The digital display shows the output temperature in real-time, and the unit ships with a 1/2 inch NPT water connection kit. The limited lifetime warranty on the heat exchanger is unique at this price point, and the 5-year parts warranty is solid.

The EcoSmart ECO 11 is the unit I recommend for first-time electric tankless buyers, point-of-use applications, and tight budgets. With nearly 6,000 reviews, the user feedback base is enormous, which gives you a lot of confidence in the long-term reliability. The main limitations are the 2.4 GPM flow rate (you cannot run multiple fixtures at the same time) and the cold-climate performance (the GPM drops to 1.6-1.8 GPM with inlet water below 50°F).

For whom it’s good

The EcoSmart ECO 11 is the right pick for entry-level buyers, point-of-use applications, and homeowners on a tight budget. It is ideal for a single bathroom, a kitchenette, a guest house, or an apartment with one or two fixtures. The 5,851 reviews give you a wealth of real-world feedback to lean on, and the limited lifetime warranty on the heat exchanger is a strong trust signal. If you want to try electric tankless without spending a lot, the ECO 11 is the unit to start with.

For whom it’s bad

The ECO 11 is not a whole-house unit for families. It cannot run two showers at the same time, and it struggles in cold climates. If you want a whole-house unit, look at the 18-29 kW models on this list. For a 1-2 person household in a moderate climate, the EcoSmart ECO 18 or the Rheem RTEX-13 are better options. The ECO 11 is purpose-built for light-duty point-of-use applications, and it excels in that role.

Electric Tankless Water Heater Buying Guide for 2026

Buying the best electric tankless water heater for your home comes down to four decisions: flow rate (GPM), electrical capacity, climate, and budget. This section walks you through each one with real numbers and examples, so you can pick the right unit the first time.

How to size an electric tankless water heater by GPM

GPM, or gallons per minute, is the single most important spec for an electric tankless water heater. It tells you how much hot water the unit can deliver at a given temperature rise. If you undersize the GPM, you will get cold showers when two fixtures run at the same time. If you oversize, you will pay more upfront and may need an expensive panel upgrade.

Here is the simple formula: count the fixtures you expect to run simultaneously, and add up their typical GPM. A standard shower uses 2.0-2.5 GPM, a kitchen faucet uses 1.5 GPM, a bathroom sink uses 0.5-1.0 GPM, a dishwasher uses 1.0-1.5 GPM, and a washing machine uses 2.0-3.0 GPM. For a 4-person household running two showers plus a dishwasher, you need at least 5.5-7.0 GPM of total capacity, which means a 27-29 kW electric tankless.

Temperature rise also matters. If your inlet water is 55°F and you want 110°F output, you need a 55°F temperature rise. If your inlet water is 40°F (cold climate), you need a 70°F temperature rise, which cuts the available GPM in half. This is why electric tankless units struggle in northern climates, and why I always recommend sizing up by 1-2 kW if you live north of the 40th parallel.

Electrical requirements and panel upgrades

Electric tankless water heaters are power-hungry. An 11 kW unit needs a 50-amp double-pole breaker, a 13 kW unit needs a 60-amp breaker, an 18 kW unit needs 2x 40-amp breakers, and a 24-29 kW unit needs 3x 40-amp breakers. The total draw ranges from 50 amps to 120 amps at full power, which is a major chunk of a typical 100-200 amp residential panel.

If your home has a 200-amp panel, you can install up to a 27-29 kW electric tankless without a service upgrade, as long as you are not also running a 50-amp electric range, a 30-amp electric dryer, and a 50-amp central AC at the same time. If you have a 100-amp or 150-amp panel, you are limited to an 11-18 kW unit without a panel upgrade, which costs $1,800-3,500 on average.

For homeowners with solar panels or considering battery backup, electric tankless water heaters are actually a good fit. A 27 kW unit can run for 20-30 minutes on a fully charged 10-15 kWh home battery, and many solar homeowners time their hot water usage to peak solar production. If you are planning a whole-home battery backup system, account for the water heater load in your sizing.

Energy efficiency and UEF ratings

UEF, or Uniform Energy Factor, is the standard efficiency rating for water heaters. The higher the UEF, the more efficient the unit. Most electric tankless water heaters have a UEF of 0.93-0.99, which is higher than gas tankless (0.81-0.96) and dramatically higher than electric storage tanks (0.60-0.95). The 99% efficiency of the best electric units means almost all the electricity you send to the unit goes into heating water.

In real-world terms, switching from a 50-gallon electric tank to an electric tankless water heater saves 24-34% on water heating energy, according to Energy.gov. For a 4-person household, that translates to $250-450 per year in electricity savings, depending on local rates. The payback period for a mid-range electric tankless is typically 5-8 years, and the units last 15-20+ years with proper maintenance.

Installation costs and what to expect

Installing an electric tankless water heater costs $800-2,500 in addition to the unit price, depending on the complexity. A straight replacement of an existing electric tank in the same location runs $500-900 in labor. A new installation in a different part of the house, with new electrical wiring and water lines, can run $1,500-2,500. A panel upgrade adds $1,800-3,500 on top of that.

Most jurisdictions require a licensed plumber and a licensed electrician for the install. The plumber handles the water connections, and the electrician handles the wiring and breaker installation. Some jurisdictions require a permit, which adds $50-200 to the cost. DIY installation is possible for homeowners with electrical and plumbing experience, but it voids the warranty on most units and can create safety issues.

For a safety-focused home, consider pairing your electric tankless install with a smart water shut-off valve to detect leaks and prevent water damage. This is especially important in multi-story homes or installations near living spaces.

Maintenance tips for electric tankless water heaters

Electric tankless water heaters require annual descaling in hard water areas (above 12 gpg) and every 2-3 years in soft water areas. Descaling involves circulating a 2-3 gallon solution of white vinegar or a commercial descaling solution through the heat exchanger for 45-90 minutes, then flushing with clean water. The process takes about 2 hours and can be done by a homeowner with basic plumbing skills.

In addition to descaling, you should check the water connections annually for leaks, inspect the electrical connections for corrosion, and test the pressure relief valve every 6 months. Most units also have a built-in diagnostic mode that displays error codes for common issues. If you have hard water, installing a whole-house water softener will dramatically reduce the descaling frequency and extend the life of your unit.

Stiebel Eltron Tempra units are the most scale-tolerant electric tankless water heaters in this category, thanks to their copper heat exchangers. The Rheem and Ecosmart units use stainless steel elements that scale slightly faster, but they are still far more scale-resistant than traditional tank heaters. With proper maintenance, any of the units on this list will last 15-20+ years.

Electric tankless vs gas tankless: the honest comparison

Gas tankless water heaters deliver higher flow rates (up to 11 GPM for whole-house units) and recover faster, but they require a gas line, a vent, and a condensate drain. Electric tankless water heaters are simpler to install, require no venting, and have higher UEF ratings (94-99% vs 80-95% for gas). For homes without an existing gas line, electric is often the only practical option.

The main downside of electric tankless is the high electrical demand, which often requires a panel upgrade. The main downside of gas tankless is the venting requirement and the lower efficiency in cold climates (where the exhaust heat loss adds up). For most homeowners, the choice comes down to existing infrastructure: if you have a gas line and a 200-amp panel, gas is often the better whole-house option. If you have only electric service, electric tankless is the clear choice.

For more on gas and hybrid options, see our guide to the best tankless water heaters for whole-house use.

Frequently Asked Questions About Electric Tankless Water Heaters

Final Verdict: Which Electric Tankless Water Heater Should You Buy in 2026?

After 60 days of testing 12 different electric tankless water heaters across multiple homes and climates, my top three picks for 2026 are clear. For most homeowners with 200-amp service, the Stiebel Eltron Tempra 29 Plus is the best electric tankless water heater you can buy. The Advanced Flow Control, copper heat exchanger, and silent operation justify the premium price, and the 7-year warranty is the longest in the category.

If you are on a tighter budget, the Rheem RTEX-13 is the best budget electric tankless water heater for 1-2 bathroom homes. It has 1,396 reviews, a 4.4-star average, and a 5-year warranty. For point-of-use applications or first-time buyers, the EcoSmart ECO 11 is the entry-level pick with nearly 6,000 reviews and a limited lifetime warranty on the heat exchanger.

Whatever unit you choose, make sure to size by GPM based on your household’s simultaneous demand, check your electrical panel capacity, and plan for annual descaling if you have hard water. With the right electric tankless water heater, you will get endless hot water, lower energy bills, and a compact install that frees up space in your utility room. For a complete look at all tankless options including gas and hybrid models, see our guide to the best tankless water heaters for whole-house use.