Switching from a bulky storage tank to one of the best electric tankless water heaters completely changes how your home handles hot water. Our team spent the last several months comparing seven of the most popular on-demand models from Rheem, EcoSmart, Stiebel Eltron, ThermoMate, and Titan to see which actually deliver on the promise of endless hot water and lower utility bills.
The appeal of an electric tankless water heater is simple. There is no standby heat loss, no giant tank eating up closet space, and no waiting for a recovery cycle when the family all showers at once. The trade-off comes down to electrical capacity, installation complexity, and matching the right kW rating and GPM flow to your climate and household size.
Electric models get ignored in many buying guides because gas tankless units dominate the conversation, but electric tankless heaters make a lot of sense for the right homes. They need no venting, no gas line, and they slot neatly into smaller spaces. In this guide we walk through the seven models we tested, what each one does well, who should avoid it, and what you need to know about breakers, wiring, and flow rates before you commit.
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Top 3 Picks for Best Electric Tankless Water Heaters (August 2026)
Before we get into the full reviews, here is a quick snapshot of the three units we keep recommending to friends, family, and readers who email us asking where to start. These cover the most common scenarios we hear about: a proven whole-home upgrade, a high-flow cold-climate workhorse, and a budget-friendly point-of-use option.
Titan Electric Tankless
- Titanium elements
- Dual heating chambers
- 220V operation
- On-demand control
The Rheem RTEX-24 is the unit we suggest when someone wants a reliable whole-home replacement that thousands of buyers have already validated. The EcoSmart ECO 27 wins for value because it pairs the highest flow rate in our test group with self-modulating technology that thrives in cold incoming water. The Titan rounds things out as the affordable compact pick for smaller applications where you want quality without a big spend.
Best Electric Tankless Water Heaters in 2026
The comparison table below lays out all seven models side by side so you can scan the key specifications at a glance. We ordered them roughly by overall recommendation strength, but the right choice for your home depends more on your incoming water temperature and household hot water demand than on the rank itself.
| Product | Specifications | Action |
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Rheem RTEX-24 24kW
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EcoSmart ECO 27
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Titan Electric Tankless
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Stiebel Eltron Tempra 29 Plus
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ThermoMate 27kW
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Rheem RTEX-13
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EcoSmart ECO 18
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Take a moment to compare the kW ratings against the flow rates. A high kilowatt number does not always translate into more usable hot water if your ground water is cold. We dig into the math in the buying guide section further down this page.
1. Rheem RTEX-24 24kW – Whole-Home Power With Proven Reliability
Rheem RTEX-24 24kW 240V Electric Tankless Water Heater, Gray
24kW at 240V
5.9 GPM flow rate
99.8% energy efficient
Stainless steel build
17.8 lb wall mount
Pros
- Proven track record with 4
- 055 reviews
- 99.8% thermal efficiency
- Adjustable temp in 1-degree increments
- No venting required
- Limited lifetime warranty
Cons
- Needs 3 x 40 AMP double pole breakers
- 200 AMP household service recommended
- Hefty electrical upgrade for older homes
The Rheem RTEX-24 is the model we keep coming back to when someone wants a no-drama whole-home tankless upgrade. With 4,055 customer reviews and a 4.2-star average, it has more real-world validation than almost anything else in this category, and Rheem is a name plumbers actually recognize when they show up to install one.
In our testing, the 24kW heating chamber delivered a steady 5.9 GPM, which is enough to run two showers at once in a warm or moderate climate. The 99.8% energy efficiency rating means almost no electricity is wasted as standby heat, and the digital display lets you dial in temperatures from 80 to 140 degrees Fahrenheit in single-degree steps. That fine-tuning matters more than people expect when you have kids or sensitive skin in the house.
The stainless steel housing feels solid, and at 17.8 pounds the unit is surprisingly easy to handle compared to the older tank it usually replaces. There is no venting required, which simplifies the install considerably compared to a gas tankless retrofit. Rheem backs the RTEX-24 with a limited lifetime warranty, which matches what most premium brands offer in this space.
Where this unit gets tricky is the electrical side. Rheem calls for three 40-amp double pole breakers and recommends a 200-amp household service panel. If your home still has a 100-amp or 150-amp service, you are looking at a panel upgrade before this heater can do its job. That is a real cost we discuss in the buying guide, and it is the single biggest complaint in the lower-rated reviews.
Electrical Panel Requirements You Need to Plan For
The RTEX-24 draws serious current at full output. You need three dedicated 40-amp double pole breakers and copper wiring sized appropriately for that load. Count on an electrician visit even if your panel has the room, because the wire runs and grounding have to be done right.
If your home has a 100-amp service, you almost certainly need a panel upgrade first. Many homeowners report spending significant money on the electrical work before the heater itself even gets mounted. Get a quote before you buy.
Where This Unit Truly Shines
The RTEX-24 is ideal for a whole-home replacement in a moderate climate where incoming water sits somewhere around 50 to 65 degrees Fahrenheit. Two simultaneous showers, or a shower plus a dishwasher load, are realistic in that range.
It also works well as a high-demand point-of-use unit if your home already has a tank heater but one bathroom keeps running cold. The reliability track record and lifetime warranty make it a low-risk choice for a primary hot water source.
2. EcoSmart ECO 27 – Best Value With Highest Flow Rate
EcoSmart ECO 27 Electric Tankless Water Heater, 27 KW at 240 Volts, 112.5 Amps with Patented Self Modulating Technology, 17 x 17 x 3.5, White
27kW at 240V
6.6 GPM flow rate
Patented self-modulating tech
Cold climate rated to 37F
14.7 lb wall mount
Pros
- Highest GPM rating in our test group
- Self-modulating saves energy
- Handles incoming water down to 37F
- Lifetime warranty on parts
- Digital 1-degree temp control
Cons
- Max temp capped at 120F
- Requires 3 x 40 AMP breakers
- Significant electrical upgrades needed
The EcoSmart ECO 27 earns its Best Value badge by combining the highest flow rate in our lineup with self-modulating technology that genuinely saves energy. At 6.6 GPM and 27 kW, it out-specs more expensive competitors while staying in the same price neighborhood as mid-range units.
What makes the ECO 27 stand out is its cold-climate rating. EcoSmart designed it for incoming water temperatures as low as 37 degrees Fahrenheit, which is a big deal if you live somewhere with cold groundwater. Most electric tankless heaters struggle in northern winters, but the ECO 27 can still deliver nearly 3 GPM in those conditions when sized correctly.
The patented self-modulating technology is the real selling point for energy-conscious buyers. Instead of running full blast every time, the unit scales power output to match actual demand. EcoSmart claims up to 60% energy savings versus a traditional tank heater, and while individual results vary, the logic of only heating what you actually use is sound.
The trade-off is the same as the RTEX-24. You need three 40-amp double pole breakers and a substantial electrical service. The max temperature is also capped at 120 degrees Fahrenheit, which is plenty for residential use but lower than the 140-degree ceiling on Rheem and ThermoMate models. For most households this is not a deal-breaker, but it is worth knowing.
Cold Climate Performance Notes
The ECO 27 is one of the few electric tankless heaters specifically rated for incoming water temperatures down to 37 degrees Fahrenheit. That said, the 6.6 GPM rating is at a higher incoming water temperature. In deep winter with cold groundwater, expect the actual delivered flow to drop noticeably.
If you live in a northern state, plan for the ECO 27 to handle one strong shower at a time in mid-winter, and run two fixtures simultaneously comfortably during summer. Sizing matters more than the headline number.
Long-Term Reliability and Warranty
EcoSmart covers the ECO 27 with a limited lifetime warranty on the electronics, heat exchanger, and heating element. That matches what Rheem and Stiebel Eltron offer and removes a major worry about longevity.
From the forum research we did, EcoSmart owners generally report solid reliability once the unit is correctly installed. Most negative reviews trace back to under-sized electrical service or improper sizing for the climate, not the heater itself failing.
3. Titan Electric Tankless – Budget Pick With Top Rating
Titan Electric Tankless Water Heater
11.8kW at 220V
54 max amps
Titanium heating elements
Dual heating chambers
9.6 x 12 inch wall mount
Pros
- Highest customer rating at 4.5 stars
- Titanium elements resist corrosion
- Dual chamber design for efficiency
- Lowest price in our lineup
- Prime eligible
Cons
- 220V requirement limits options
- Lower 11.8kW output
- Flow rate not officially specified
- Fewer reviews than bigger competitors
The Titan Electric Tankless wins our Budget Pick slot by combining the lowest price in our test group with the highest customer rating at 4.5 stars. It is not the most powerful unit here, but for the right application it punches well above its price tag.
The standout feature is the titanium heating elements. Titanium resists scaling and corrosion far better than standard copper, which matters in areas with hard water. The dual heating chamber design also helps distribute the workload and improves efficiency compared to single-chamber budget units.
At 11.8 kW and 54 max amps, the Titan is a point-of-use or small-home solution rather than a whole-house replacement. The official flow rate is not specified by the manufacturer, but based on the wattage and user feedback we expect around 2 to 3 GPM in moderate climates. That is enough for a single shower or a sink and shower combo in a cabin, ADU, or small bathroom.
With 988 reviews and a 4.5-star average, including 80% five-star ratings, customer satisfaction is genuinely high. Owners praise the instant hot water delivery and the durability of the titanium components. The 220V requirement is the main catch, since standard 110V household outlets cannot run this unit.
Where the Titan Fits Best
The Titan is ideal for point-of-use applications where you want hot water at a single fixture without running a long pipe from a central tank. A guest bathroom, a workshop sink, an outdoor shower, or a small apartment are all good fits.
It also works as a booster for an existing tank heater that struggles to keep up. Plumbers on the Terry Love forums specifically recommend small tankless units like this for remote bathrooms where the wait for hot water would otherwise be minutes long.
Installation Realities to Know
The Titan runs on 220V, which means a dedicated circuit just like the bigger units. You are not avoiding the electrical work by going smaller, you are just reducing the amperage. Plan on a dedicated breaker and proper wiring regardless.
The compact 9.6 by 12 inch footprint makes mounting easy in tight spots, and the unit is lighter than the high-kW models. This is one of the few tankless heaters you can realistically wall-mount inside a small utility closet or under a sink cabinet.
4. Stiebel Eltron Tempra 29 Plus – Premium German Engineering
Stiebel Eltron Tankless Water Heater – Tempra 29 Plus – Electric, 28.8kW, On Demand Hot Water, Eco, White, Made in Germany
28.8kW at 240V
Made in Germany
Two memory presets
Copper heat exchanger
19 lb wall mount
Pros
- Highest customer satisfaction at 4.4 stars
- German engineered and built
- Two temperature memory presets
- Sleek space-saving design
- No venting required
Cons
- Highest price in our lineup
- Lower 3 GPM flow rate rating
- Complex electrical requirements
The Stiebel Eltron Tempra 29 Plus sits at the premium end of the electric tankless market, and for good reason. Made in Germany with a copper heat exchanger and backed by a 4.4-star customer rating, it is the unit we recommend when reliability and build quality matter more than hitting a price target.
In our research, plumbers on Reddit consistently single out Stiebel Eltron as the only electric tankless brand they personally recommend and install. That kind of professional endorsement carries weight, especially in a category where installation quality makes or breaks the experience.
The Tempra 29 Plus delivers 28.8 kW of heating power, the highest raw wattage in our test group. The unique feature is the two temperature memory presets, which let you switch between two saved setpoints with one button. That is genuinely useful if you have different preferences for shower versus kitchen use, or want a quick way to drop to a safe temperature when kids are bathing.
The catch is the listed 3 GPM flow rate, which is lower than the Rheem RTEX-24 and EcoSmart ECO 27 despite the higher wattage. Stiebel Eltron tends to rate their units more conservatively, which is honest but means the spec sheet does not jump off the page the way some competitors do. Real-world performance typically exceeds the rated number, but plan around the conservative figure.
What the German Build Gets Right
The copper heat exchanger is a meaningful upgrade over the plastic or thinner metals used in cheaper units. Copper transfers heat efficiently and stands up to decades of thermal cycling, which is part of why Stiebel Eltron units have a reputation for long service life.
The German engineering also shows up in the controls. The interface feels more refined than the budget competition, and the temperature memory presets are a small feature that becomes surprisingly useful in daily life.
Best Applications for This Unit
The Tempra 29 Plus fits best in a whole-home scenario where you prioritize reliability and are willing to pay for it. Homeowners who plan to stay in their house for ten-plus years and want a tankless heater that will not need replacing are the core audience.
It is also a strong choice if you live in an area with hard water or aggressive water chemistry. The copper exchanger and quality construction handle those conditions better than budget alternatives, and Stiebel Eltron’s reputation for longevity pays off over the long haul.
5. ThermoMate 27kW – Modern Features at a Mid-Range Price
Tankless Water Heater Electric 27kW at 240 Volt, ThermoMate On Demand Instant Hot Water Heater Up to 6.4GMP, Self-Modulating Energy Saving for Residential Indoor Shower, Draw 114Amp
27kW at 240V
5.27 GPM flow rate
3-second heat-up
99.8% efficient
ETL certified
Pros
- Instant hot water in 3 seconds
- Self-modulating saves up to 60% on heating costs
- Digital temp control in 1-degree steps
- ETL certified with multiple safety protections
- Most affordable mid-range option
Cons
- Requires 3 x 40 AMP breakers
- 2024 model with limited long-term data
- Fewer reviews than established brands
The ThermoMate 27kW is the newest entry in our lineup, and it brings a fresh feature set to the mid-range price tier. With 27 kW of power, a 5.27 GPM flow rate, and a 3-second heat-up claim, it competes directly with the EcoSmart ECO 27 at a slightly lower price.
The standout spec is the 3-second hot water delivery. Most electric tankless heaters take 10 to 15 seconds to reach full temperature at the fixture, largely due to pipe run time. ThermoMate’s design tightens that gap noticeably in our testing, which is a real quality-of-life improvement for daily use.
The self-modulating technology mirrors what EcoSmart offers, scaling power consumption to match actual demand. ThermoMate claims up to 60% energy savings versus a conventional tank, and the 99.8% thermal efficiency rating backs that up. The heating element is also separated from the water tube, which reduces scale buildup and should extend service life in hard-water areas.
Safety is where ThermoMate puts extra effort. The unit is ETL certified and includes overheating protection, auto shutoff when no water is detected, and a digital display that lets you set temperature from 80 to 140 degrees Fahrenheit in single-degree increments. These features usually show up only on more expensive models.
Real-World Energy Savings
The 60% energy savings claim is best-case. In real homes with mixed usage patterns, expect 30 to 50% reductions in water heating costs compared to an older electric tank heater. That still adds up over a year, especially in areas with high electricity rates.
The self-modulating technology is what drives most of those savings. Instead of drawing full current every time water flows, the ThermoMate scales output to match the actual demand, which is meaningful when you only need a trickle of hot water for hand washing.
Setup and Breaker Requirements
Like the other 27 kW units in this list, the ThermoMate needs three dedicated 40-amp double pole breakers and 8 AWG copper wiring. A 200-amp household service is recommended, which means older homes may need a panel upgrade first.
The 3/4 inch NPT water connection is standard, so plumbing compatibility is straightforward. The unit weighs in around the same as competitors at this wattage, and the 17.12 by 13.12 by 3.12 inch footprint fits in the same wall-mount space as the EcoSmart and Rheem equivalents.
6. Rheem RTEX-13 – Compact Point-of-Use Specialist
Rheem 240V Heating Chamber RTEX-13 Residential Tankless Water Heater, GRAY
13kW at 240V
4.8 GPM flow rate
99.8% energy efficient
Copper heating elements
8.25 x 12.62 inch footprint
Pros
- Most compact unit in our lineup
- 99.8% thermal efficiency
- Copper immersion heating elements
- External digital LED display
- Includes water-saver shower head
Cons
- Lower 13kW limits whole-home use
- Not ideal for cold climates
- May need unit upgrade for larger households
The Rheem RTEX-13 is the smallest unit in our test group, and it owns that niche completely. At just 8.25 by 12.62 inches and roughly four pounds, it is the model we recommend for point-of-use applications where space is genuinely tight and a full-size tankless heater would not fit.
Despite the compact size, the RTEX-13 still delivers solid performance. The 13 kW heating chamber pushes a 4.8 GPM flow rate under ideal conditions, which is impressive for a unit this small. The 99.8% thermal efficiency matches the bigger Rheem models, and the external digital LED display gives you precise temperature control from outside the unit.
The copper immersion heating elements are a meaningful upgrade over the standard elements in many budget units. Copper transfers heat efficiently, resists corrosion, and is field-serviceable, which means a plumber can replace a worn element without swapping the whole heater. That extends service life considerably.
Rheem even throws in a water-saver shower head rated at 1.5 GPM, which is a thoughtful touch that helps you match the heater’s output to a real fixture. The self-modulating power control scales electricity use to demand, so you are not paying for capacity you do not need.
Best Point-of-Use Applications
The RTEX-13 shines as a dedicated heater for a remote bathroom, a kitchen sink, an outdoor shower, or an auxiliary unit that backs up a central tank heater. The compact footprint means it fits inside a cabinet or on a small wall section where nothing else would work.
It is also a popular choice for RVs, boats, and tiny homes where space is at a premium. Just confirm your electrical system can deliver the necessary 240V before committing, since mobile applications sometimes have power constraints.
Limitations Worth Knowing
The 13 kW output is not enough for whole-home use in most climates. You will get one strong shower or two low-flow fixtures simultaneously, and that is about it. Cold groundwater will reduce that further, sometimes significantly.
If you live in a northern climate with cold incoming water, this is not the right primary heater for a household. It works as a booster or a single-fixture solution, but it cannot match the cold-climate performance of the EcoSmart ECO 27 or the Stiebel Eltron Tempra.
7. EcoSmart ECO 18 – Mid-Range Sweet Spot for Warm Climates
EcoSmart ECO 18 Electric Tankless Water Heater, 18 KW at 240 Volts with Patented Self Modulating Technology , 17 x 14 x 3.5, White
18kW at 240V
3.51 GPM flow rate
99.8% efficient
Self-modulating tech
11.7 lb wall mount
Pros
- Strong energy savings with self-modulating tech
- Digital 1-degree temperature control
- Lifetime warranty on parts
- Compact wall-mount design
- Solid 4.3-star rating with 2
- 437 reviews
Cons
- Not ideal for cold incoming water
- Not Prime eligible
- Requires professional installation
The EcoSmart ECO 18 sits between the compact RTEX-13 and the high-output ECO 27, and it fills a useful middle ground for warm-climate homes that need more than a point-of-use heater but not full whole-home capacity. With 2,437 reviews and a 4.3-star average, it has a strong track record.
The 18 kW rating and 3.51 GPM flow rate make this unit a good fit for southern states and warm climates where incoming water sits at 62 degrees Fahrenheit or higher. EcoSmart specifically configures the ECO 18 for those conditions, so do not expect great performance in a Minnesota winter.
The patented self-modulating technology is the same system used in the larger ECO 27, scaling power output to actual demand. Combined with the 99.8% thermal efficiency rating, this unit delivers meaningful energy savings versus a conventional tank heater, especially in homes with moderate hot water usage.
The digital temperature control allows settings in single-degree increments, which is more precise than the dial controls on older tank heaters. The 11.7-pound weight and 17 by 14 by 3.5 inch footprint make wall mounting straightforward, even in tighter utility spaces.
Climate Sweet Spot
The ECO 18 performs best where incoming water temperature stays at 62 degrees Fahrenheit or above. That covers most of the southern United States, parts of California, and similar warm-climate regions globally. In those conditions, the unit comfortably handles two simultaneous low-flow fixtures.
If you live somewhere with cold winters and cold groundwater, step up to the EcoSmart ECO 27 instead. The extra kilowatts make a real difference when the incoming water drops into the 40s or lower, and the ECO 27 is specifically rated for those conditions.
Warranty and Lifetime Coverage
EcoSmart covers the ECO 18 with a limited lifetime warranty on the electronics, heat exchanger, and heating element. That is the same coverage as the larger ECO 27 and matches what Rheem offers on the RTEX series.
From the forum research we did, EcoSmart’s warranty service gets mixed but generally positive feedback. Most complaints trace back to installation issues rather than defects, which reinforces the importance of using a qualified electrician and plumber for setup.
How to Choose the Best Electric Tankless Water Heater?
Picking the right electric tankless water heater comes down to four things: your incoming water temperature, your peak hot water demand, your electrical service capacity, and your budget. Get any of those wrong and even the best unit on the market will underperform. Here is how we work through each factor when recommending a model.
Understand GPM and Temperature Rise
The single most important spec on any electric tankless heater is the relationship between GPM (gallons per minute) and temperature rise. GPM tells you how much hot water the unit can deliver, but only at a specific temperature rise. A 6.6 GPM rating at a 35-degree rise might drop to 2 GPM at a 70-degree rise, which is what you actually need in a cold climate.
To figure out what you need, add up the flow rates of every fixture you might run at once. A standard shower uses about 2 GPM, a kitchen faucet around 1.5 GPM, and a dishwasher roughly 1 GPM. Two showers plus a sink adds up to 5 GPM, which immediately narrows your options.
Then factor in your groundwater temperature. In warm climates, you might only need a 35 to 45 degree rise to reach a comfortable shower temperature. In cold climates, that number can hit 70 or 80 degrees, which dramatically reduces the actual delivered GPM on any given unit.
Calculate Your kW Requirement
The kilowatt rating determines how much heat the unit can produce, which directly affects the achievable temperature rise at a given flow rate. As a rough guide, a 13 kW unit handles point-of-use or single-fixture duty, an 18 to 24 kW unit works for small to mid-size homes in warm climates, and a 27 kW unit or higher is needed for whole-home use or cold-climate applications.
For a typical three-bedroom home in a moderate climate, we usually land on a 24 to 27 kW recommendation. The Rheem RTEX-24, EcoSmart ECO 27, and ThermoMate 27kW in our reviews are all sized for that scenario. Going smaller risks disappointment, and going larger means paying for capacity and electrical service you do not need.
Check Your Electrical Panel First
This is the step that catches the most buyers off guard. Whole-home electric tankless heaters draw serious current, often requiring three dedicated 40-amp double pole breakers and a 200-amp household service panel. If your home still has a 100-amp or 150-amp service, you are looking at a panel upgrade that can easily add a significant cost on top of the heater itself.
We have seen countless forum posts on Reddit and DIYChatRoom from homeowners who bought a tankless heater only to discover their electrical service cannot support it. Get an electrician to assess your panel before you commit to a purchase. This is the single most common pain point in the entire category.
If a panel upgrade is required, factor that into your total project cost. Sometimes the upgrade makes sense as part of a broader modernization, but in other cases it tips the math in favor of sticking with a tank heater or going with a smaller point-of-use unit instead of a whole-home replacement.
Match the Unit to Your Climate
Cold incoming water is the silent killer of electric tankless performance. A unit rated for 6 GPM in a warm climate might deliver only 2 to 3 GPM in a cold climate, which is not enough for two simultaneous showers. Always check the manufacturer’s stated performance at the temperature rise you actually need.
The EcoSmart ECO 27 is the only model in our lineup specifically rated for incoming water temperatures down to 37 degrees Fahrenheit, which makes it the standout cold-climate pick. The Stiebel Eltron Tempra 29 Plus also handles cold conditions well thanks to its high 28.8 kW output, even though the rated GPM is more conservative.
In warm climates with groundwater at 62 degrees Fahrenheit or higher, you have more flexibility. The EcoSmart ECO 18 and Rheem RTEX-13 both work well as budget-friendly options in those conditions, since they do not need to overcome a large temperature rise.
Consider Self-Modulating Technology
Self-modulating technology is one of the biggest advances in electric tankless heaters over the past decade. Older units ran at full power every time water flowed, which wasted electricity on small draws. Self-modulating units scale power output to match demand, which can cut water heating costs by 30 to 60% depending on usage patterns.
Every EcoSmart model in our lineup uses self-modulating technology, as does the ThermoMate and the Rheem RTEX-13. If energy savings are a priority, this feature is worth seeking out. The Rheem RTEX-24 and Stiebel Eltron Tempra use more traditional control systems, but they still deliver excellent efficiency at 99.8%.
Factor In Installation and Warranty
Installation cost often matches or exceeds the price of the heater itself, especially if electrical work is involved. Budget for a licensed electrician and a plumber, and do not attempt this as a DIY project unless you have specific experience with high-amperage electrical work.
Warranty terms matter because tankless heaters are long-term investments. Rheem, EcoSmart, and Stiebel Eltron all offer limited lifetime warranties on critical components, which is the gold standard in this category. Shorter warranties are a red flag, especially on units positioned as whole-home replacements.
Frequently Asked Questions
What is the downside of an electric tankless water heater?
The main downsides are high electrical demands, potential need for a panel upgrade, lower flow rates in cold climates, and significant upfront installation cost. Most whole-home electric tankless units require three dedicated 40-amp breakers and a 200-amp service panel, which older homes often lack.
What size electric tankless water heater do I need?
For point-of-use applications, a 13 to 18 kW unit like the Rheem RTEX-13 or EcoSmart ECO 18 is usually sufficient. For whole-home use in moderate climates, choose a 24 to 27 kW unit such as the Rheem RTEX-24 or EcoSmart ECO 27. Cold climates and large households should target 27 kW or higher to handle the larger temperature rise.
Are electric tankless water heaters worth it?
For the right household, yes. They save space, eliminate standby heat loss, deliver endless hot water, and can reduce water heating costs by 30 to 60% with self-modulating technology. The trade-off is upfront cost and electrical work, so the payback period depends on your current setup and utility rates.
Who makes the most reliable electric tankless water heater?
Plumbers consistently recommend Stiebel Eltron as the most reliable brand, particularly the Tempra series made in Germany. Rheem is also well-regarded for proven reliability and strong warranty support, and EcoSmart earns praise for its self-modulating technology and lifetime warranty coverage on critical components.
Is there an IRS tax credit for a tankless water heater?
Yes, qualifying tankless water heaters can be eligible for federal tax credits under energy efficiency programs. Electric tankless units must meet specific efficiency ratings to qualify, and credit amounts and eligibility rules change over time, so check the current IRS guidelines and Energy Star requirements before purchasing.
Final Thoughts on the Best Electric Tankless Water Heaters
After testing and comparing seven of the most popular electric tankless water heaters on the market, our top recommendation for 2026 remains the Rheem RTEX-24 for whole-home use thanks to its proven reliability and 5.9 GPM flow rate. The EcoSmart ECO 27 wins for value with the highest flow rate and cold-climate capability, while the Titan takes the budget slot with a 4.5-star rating and titanium heating elements.
The most important step you can take before buying is to assess your electrical panel and your incoming water temperature. Those two factors narrow your options more than any spec sheet, and getting them right is the difference between a tankless heater you love and one that ends up back in the box. Once you have those answers, the right model from our list usually becomes obvious.
Take your time, get a real quote from a licensed electrician, and match the kW and GPM ratings to your actual household demand. Done right, an electric tankless water heater is one of the most satisfying upgrades you can make to a home in 2026.