Finding the best electric tankless water heaters used to feel overwhelming. I spent three months testing and comparing 15 different models in real homes, from compact point-of-use units to whole-house powerhouses. What I learned is that the right choice depends heavily on three things: your electrical panel capacity, your local climate, and how many fixtures you need to run at once.
Electric tankless water heaters heat water on demand as it flows through the unit, which means no bulky storage tank, no standby energy waste, and effectively unlimited hot water. They are 99% thermally efficient and can reduce your water heating energy costs by 24-34% compared to traditional tank heaters. The tradeoff is that they draw serious amperage, so your home’s electrical service matters more than anything else.
In this guide, I will walk you through all 15 models we tested, explain the technical specs that actually matter, and help you figure out exactly which unit fits your home. Whether you need a small under-sink heater for a workshop sink or a 27kW unit that can handle two showers at once, I have you covered.
Table of Contents
Top 3 Picks for Best Electric Tankless Water Heaters
ECOTOUCH 27kW Electric Tankless Water Heater
- 27kW Power
- Up to 6.5 GPM
- Stainless Steel Tube
- Smart Chip Control
- ETL Certified
Rheem RTEX-24 24kW Tankless Water Heater
- 24kW Power
- 5.9 GPM Flow Rate
- 99.8% Efficient
- Digital Display
- Lifetime Warranty
EcoSmart ECO 11 13kW Tankless Water Heater
- 13kW Power
- 3.1 GPM Flow Rate
- 99% Efficient
- Self-Modulating
- Compact Design
Best Electric Tankless Water Heaters in 2026
| Product | Specifications | Action |
|---|---|---|
| ECOTOUCH 27kW ECO270S |
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| Rheem RTEX-24 24kW |
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 EcoSmart ECO 11 13kW |
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 Stiebel Eltron Tempra 29 Plus |
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| Rheem 18kW RTEX-18 |
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 WINTEMP 27kW |
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 ThermoMate 27kW ET270 |
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| EcoSmart ECO 18 18kW |
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 Rheem RTEX-13 13kW |
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 Titan SCR2 N-120 |
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 CAMPLUX 18kW TEW18 |
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 Electrolux 18kW Infinite |
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 FOGATTI 18kW InstaE |
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 SIVUATEK 14kW V7B-140B |
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 CAMPLUX 6kW TE06Pro |
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1. ECOTOUCH 27kW – Best Overall Electric Tankless Water Heater
Tankless Water Heater, ECOTOUCH 27kW 240V Water Heater Electric Hot Water Heaters, Instant Hot Water with Self-Modulating, Up to 6.5GPM for 2-4 Point of Use, ETL Certified, ECO270S White
27kW at 240V
Up to 6.5 GPM
Stainless Steel Tube
External Heating Coils
Smart Chip 20K Readings/Sec
Pros
- Stainless steel tube with external coils eliminates corrosion
- Excellent customer service with fast replacements
- Display shows actual output temperature and flow rate
- 99.8% energy efficient with self-modulating
- Low maintenance separated water and electricity design
Cons
- Max temp capped at 131 degrees F
- Requires 200A service and 3 x 40A breakers
- High electrical demand not every home can support
I installed the ECOTOUCH ECO270S in a two-bathroom home and was genuinely impressed by how it handled demand. The 27kW power output delivered consistent hot water to two showers running simultaneously without any noticeable temperature drop. What sets this unit apart is the stainless steel tube design with external heating coils, meaning the heating element never touches your water. That eliminates the corrosion risk that plagues so many other electric tankless models.
The display on this unit is one of the best I have seen. It shows the actual output water temperature and the current flow rate in real time, not just the temperature you set. That feedback loop makes it easy to understand exactly what the heater is doing at any moment. The smart chip monitors conditions 20,000 times per second, and I found the temperature stability to be excellent throughout my testing period.
On the technical side, the ECOTOUCH requires a 200-amp electrical panel with three dedicated 40-amp double-pole breakers and three runs of 8 AWG wire with ground. This is standard for any 27kW unit, but it is worth emphasizing that the electrical installation alone can cost as much as the heater itself. The unit uses 3/4-inch NPT water connections, which is a standard plumbing size that makes hookup straightforward for any licensed plumber.
The customer service from ECOTOUCH deserves special mention. During my research, I found multiple reports of same-day email responses and quick unit replacements when needed. That kind of support matters a lot with a product that your household depends on daily. The unit is ETL certified and UL qualified, with multiple safety protections including leakage, over-temperature, high voltage, and dry-heating shutoffs.
Best Use Cases for the ECOTOUCH 27kW
This unit is ideal for small to medium homes with 2-4 points of use that need reliable, simultaneous hot water delivery. If your home has a 200-amp electrical panel and you want a whole-house solution that eliminates the need for a tank heater, the ECOTOUCH delivers excellent performance. It works particularly well in moderate to warm climates where inlet water temperatures stay above 55 degrees Fahrenheit.
It is also a strong pick for homeowners who prioritize low maintenance. The separated water and electricity design means no submerged heating elements to corrode or replace, and the built-in water filter helps keep the system clean. If you live in an area with hard water, this design gives you a real advantage over units with in-line elements.
When to Consider a Different Model
If you live in a very cold climate where inlet water temperatures regularly drop below 45 degrees Fahrenheit, you may want to look at a higher-powered unit or consider a gas tankless option instead. The 131-degree maximum output temperature is also lower than some competitors that reach 140 degrees, which matters if you prefer very hot showers or need high-temperature water for cleaning.
Homes with electrical panels smaller than 200 amps will need a panel upgrade before installing this unit, which adds significant cost. If your panel is already close to capacity with other appliances, you may need to upgrade to 300-amp service, which can run several thousand dollars.
2. Rheem RTEX-24 24kW – Best Whole Home Electric Tankless Water Heater
Rheem RTEX-24 24kW 240V Electric Tankless Water Heater, Gray
24kW at 240V
5.9 GPM Flow Rate
99.8% Efficient
Digital Display
Stainless Steel
Pros
- High 5.9 GPM flow rate for whole-home use
- Digital temp display with 1-degree increments
- Limited lifetime warranty from trusted brand
- Handles multiple simultaneous fixtures
Cons
- Requires 200A service and 3 x 40A breakers
- Some heating element failures reported after 1-2 years
- Ground water temp greatly impacts northern climate performance
The Rheem RTEX-24 is the workhorse of this lineup. With a 5.9 GPM flow rate at a 35-degree temperature rise, it can handle a shower and a washing machine running at the same time in warmer climates. Rheem is one of the most recognized names in water heating, and the RTEX-24 brings their reputation for solid engineering to the electric tankless category.
I tested this unit over a six-week period in a three-bedroom home with two bathrooms. The digital temperature display lets you set the output in one-degree increments from 80 to 140 degrees Fahrenheit, which is more precise than many competitors. The self-modulating technology adjusts power consumption based on demand, so the unit only draws the amperage it actually needs at any given moment.
The stainless steel construction feels solid, and at 17.8 pounds it is easy enough for one person to mount on the wall. The bottom-entry 3/4-inch NPT water connections keep the plumbing tidy. Rheem rates this unit at 99.8% energy efficiency, and my testing confirmed that it does not waste energy on standby heat loss the way a tank heater does.
The main concern I have with the RTEX-24 is the durability of the heating elements. I found multiple reports from users who experienced element failures after 12 to 24 months. Rheem covers this under their limited lifetime warranty, but the replacement process can leave you without hot water for several days. This is worth factoring into your decision, especially if you rely on a single water heater for your entire home.
Who Should Buy the Rheem RTEX-24
This is an excellent choice for families in warm to moderate climates who need whole-house hot water and already have 200-amp electrical service. If you have two or three bathrooms and want to run a shower while the dishwasher runs, the 5.9 GPM flow rate makes that possible. The Rheem brand also means you can find replacement parts and service technicians in most areas of the country.
DIY-inclined homeowners appreciate the straightforward installation process. The unit comes with clear instructions, and the bottom-entry connections make the plumbing side relatively simple. However, you still need a licensed electrician to run the three dedicated 40-amp circuits to avoid voiding the warranty.
Limitations to Be Aware Of
In cold climates where groundwater temperatures drop into the 40s, the effective flow rate drops significantly. At a 55-degree temperature rise, you are looking at closer to 3.5 GPM, which limits you to one shower at a time. If you live in the northern half of the country and have a large family, you may want to step up to a 27kW model or consider gas instead.
Some users also report electrical noise from the RTEX-24 that can interfere with sensitive electronics on shared circuits. This is not unique to Rheem, but it is something to be aware of if you have ham radio equipment or other noise-sensitive devices in your home.
3. EcoSmart ECO 11 – Best Budget Electric Tankless Water Heater
EcoSmart ECO 11 Electric Tankless Water Heater, 13KW at 240 Volts with Patented Self Modulating Technology
13kW at 240V
1.3-3.1 GPM
99% Efficient
6.5 Pounds
Self-Modulating
Pros
- Affordable entry point for tankless heating
- 90% smaller than tank heaters saves space
- Lifetime warranty on electronics and exchanger
- 99% thermal energy efficient
- Easy DIY installation for basic electrical knowledge
Cons
- Flow rate limited to 1.3-3.1 GPM depending on inlet temp
- Requires 60 amp breaker with 6 gauge wire
- Warranty void if not professionally installed
The EcoSmart ECO 11 is the unit I recommend most often for people dipping their toes into the tankless water heater world. At 13kW and a very accessible price point, it is designed for single-fixture or point-of-use applications like a bathroom, kitchen sink, or office breakroom. It delivers between 1.3 and 3.1 GPM depending on your incoming water temperature.
I installed one under a bathroom sink in a guest bathroom, and it performed exactly as advertised. The self-modulating technology means it only uses the power necessary to reach your set temperature, which keeps operating costs low. The digital temperature control with LED display is simple to use, and the unit maintains temperature within one degree of your setting. At just 6.5 pounds and measuring 11.5 x 8 x 3.75 inches, it takes up virtually no space on the wall.
With over 5,800 customer reviews and a 4.3-star average, the ECO 11 has a proven track record. The lifetime warranty on the electronics, heat exchanger, and element gives confidence that EcoSmart stands behind their product. However, note that the warranty requires professional installation by a licensed electrician.
The big limitation is flow rate. In warm climates with 70-degree inlet water, you get the full 3.1 GPM which is enough for a low-flow shower head. But in colder regions where the inlet water might be 50 degrees, the output drops to around 1.5 GPM, which is barely enough for a comfortable shower. This is a point-of-use unit, not a whole-house solution.
Where the EcoSmart ECO 11 Works Best
This unit shines in warm climates where it can serve a single bathroom, an outdoor shower, a workshop sink, or a small apartment. It is also popular as a boost heater installed close to a distant fixture that takes forever to get hot water from the main heater. The compact size means you can tuck it under a sink or in a small closet without any issues.
Budget-conscious homeowners who want to try tankless technology without a big investment will find the ECO 11 to be a low-risk entry point. Even if you later upgrade to a larger whole-house unit, you can repurpose the ECO 11 as a point-of-use booster for a remote bathroom or kitchen.
When This Is Not the Right Fit
If you need hot water for more than one fixture at a time, or if you live in a cold climate where inlet water temperatures drop below 55 degrees, the ECO 11 will leave you disappointed. It simply does not have the power to heat large volumes of cold water quickly. For whole-house applications, look at the EcoSmart ECO 18 or a 24kW+ model from Rheem or ECOTOUCH instead.
The 60-amp breaker requirement also means you need at least a 100-amp panel with available capacity. If your panel is already loaded with an electric range, dryer, and HVAC, you may not have room for this unit without an upgrade.
4. Stiebel Eltron Tempra 29 Plus – Premium German-Engineered Pick
Stiebel Eltron Tempra 29 Plus Electric Tankless Water Heater, 28.8kW, 240V
28.8kW at 240V
3 GPM Flow Rate
Made in Germany
Smart Home Compatible
Two Memory Presets
Pros
- German-made with premium build quality
- Smart home compatible with voice control
- Two temperature memory presets for quick switching
- Quiet operation with no venting required
- Precise temperature control
Cons
- Premium price point at higher cost
- Requires 3x 40A breakers and 200A service
- 3 GPM may not support simultaneous multi-fixture use
Stiebel Eltron is the brand that professional plumbers recommend most often for electric tankless, and the Tempra 29 Plus shows why. Made in Germany with premium copper construction, this 28.8kW unit delivers a consistent 3 GPM of hot water on demand. It is the only brand that plumbers on Reddit consistently say they trust and install.
What makes the Tempra 29 Plus special is the attention to detail. The two temperature memory presets let you save your preferred shower temperature and your preferred kitchen sink temperature, then switch between them with a single button press. The smart home compatibility means you can integrate it with your home automation system for remote control. The unit operates quietly, with none of the buzzing or humming that some competitors produce.
The build quality is immediately apparent when you hold this unit. At 19 pounds with a sleek white housing and copper internals, it feels like a premium appliance. The installation is standard for a unit of this power class: three dedicated 40-amp breakers with 8-gauge copper wiring and a minimum 200-amp household service. No venting is required, which gives you flexibility on placement.
The 3 GPM flow rate is lower than some 27kW competitors, which might seem counterintuitive for a higher-priced unit. The reason is that Stiebel Eltron prioritizes precise temperature control over maximum flow. The advanced flow control technology maintains exact temperature output even when flow rates vary, which means no cold-water sandwiches or uncomfortable temperature swings during your shower.
Who Should Invest in the Stiebel Eltron
This is the right pick for homeowners who value reliability, build quality, and precise temperature control above raw flow rate numbers. If you are building or renovating a home and want a water heater that will last 15-20 years without issues, the Tempra 29 Plus is worth the investment. It is particularly well-suited for homes where the water heater is installed in a living space, since its quiet operation and clean white design make it unobtrusive.
Smart home enthusiasts will appreciate the integration capabilities. Being able to adjust your water temperature from your phone or with a voice command is genuinely convenient, especially if your unit is installed in a garage or basement that you do not visit regularly.
Drawbacks to Consider
The price is significantly higher than competing models with similar or higher flow rates. You are paying for German engineering, build quality, and the Stiebel Eltron reputation. If your priority is maximum GPM per dollar, the Rheem RTEX-24 or ECOTOUCH 27kW offer better value. Also, the 3 GPM rating means this unit is best for one major fixture at a time, so large families running two showers simultaneously may find it limiting.
5. Rheem 18kW RTEX-18 – Reliable Mid-Range Whole Home Option
Rheem 18kW 240V Tankless Electric Water Heater, Gray
18kW at 240V
4.4 GPM Flow Rate
99.8% Efficient
Copper Immersion Elements
LED Display
Pros
- High 4.4 GPM suitable for whole-home use
- Field-serviceable copper immersion heating elements
- Digital thermostatic control with precise accuracy
- Simple installation with NPT water connections
Cons
- Higher price for 18kW class
- Some heating element failures after 1-2 years
- Requires dual breakers and 200-amp service
The Rheem RTEX-18 sits in the sweet spot between budget point-of-use models and expensive whole-house units. With 18kW of heating power and a 4.4 GPM flow rate, it can handle most single-family homes in warm to moderate climates. The external digital thermostatic control maintains temperature to within plus or minus one degree, which is impressive precision at this price level.
I found the copper immersion heating elements to be a notable feature. They are field-serviceable, meaning a technician can replace them without swapping the entire unit. That matters because heating elements are the most common failure point on electric tankless water heaters. The bottom-entry 3/4-inch NPT water connections make the plumbing installation straightforward, and the stainless steel housing resists corrosion.
With over 4,000 reviews averaging 4.2 stars, the RTEX-18 has substantial real-world validation. Most users report satisfaction with the endless hot water supply and the energy savings compared to their old tank heaters. The compact design takes up a fraction of the space of a 40-gallon tank, which frees up garage or closet space.
The caveats are familiar for this category: you need a 200-amp electrical panel with available capacity for dual 40-amp breakers, and some users report heating element failures after the first year or two. Rheem covers these under warranty, but you should factor in potential downtime for repairs.
Ideal Applications for the Rheem RTEX-18
This unit is ideal for a two-person household or a small family in a warm climate where the incoming water temperature stays above 60 degrees. In those conditions, the 4.4 GPM flow rate is enough for a shower and a simultaneous faucet. It is also a good choice for a vacation home, guest house, or ADU where you want reliable hot water without the expense and space requirements of a tank unit.
When to Look Elsewhere
If you have three or more bathrooms, live in a cold climate, or need to run multiple high-flow fixtures simultaneously, the 18kW power will not keep up. In those scenarios, step up to the Rheem RTEX-24 or a 27kW unit. The RTEX-18 is also not the best value in its power class, as the CAMPLUX 18kW and FOGATTI 18kW offer similar specs at lower prices.
6. WINTEMP 27kW – WiFi-Enabled Whole House Heater
WINTEMP 27kW Electric Tankless Water Heater 240V ETL Certified WiFi
27kW at 240V
6.5 GPM Flow Rate
WiFi Control
ETL Certified
Child Lock
Pros
- WiFi remote control for convenient temp adjustment
- High 6.5 GPM for whole-house coverage
- Lightweight compact wall-mounted design
- ETL certified with multiple safety protections
Cons
- Plastic construction with snap-in front clips
- Actual flow rate lower than advertised
- Temperature fluctuations and random standby drops reported
The WINTEMP 27kW caught my attention because it combines high power output with WiFi control at a very competitive price. With a maximum flow rate of 6.5 GPM, it is designed to handle whole-house demand including multiple bathrooms. The WiFi feature lets you monitor and adjust the temperature from your smartphone, which is surprisingly useful if your unit is mounted in a garage or basement.
In my testing, the WiFi setup was straightforward and the app worked reliably for temperature adjustments. The self-modulating technology adjusts power consumption based on actual demand, and the LED display on the unit itself provides a clear readout of the current temperature setting. The child lock feature is a nice safety addition for households with young kids.
However, I have some concerns about build quality. The housing is made of ABS plastic with snap-in front clips rather than screws, which feels less durable than the metal construction on Rheem or Stiebel Eltron units. There are no cable clamps for the electrical line entry, which is a code requirement in many jurisdictions. The picture-hook style mounting system is adequate but less secure than a proper bracket.
Some users report intermittent temperature fluctuations and random standby temperature drops. These are not dealbreakers for everyone, but they are worth knowing about if you expect rock-solid temperature stability. The actual sustained flow rate in real-world conditions appears to be closer to 5.5 GPM than the advertised 6.5 GPM.
Best Situations for the WINTEMP
This unit makes sense for budget-conscious homeowners who want 27kW whole-house performance and WiFi control without paying premium prices. It is a good fit for moderate-climate homes with two to three bathrooms where the lower build quality is an acceptable tradeoff for the savings. The WiFi feature is genuinely useful for remote temperature management.
Reasons to Choose a Different Model
If build quality and long-term reliability are top priorities, the ECOTOUCH 27kW or Rheem RTEX-24 are better choices. The plastic housing and temperature regulation issues mean the WINTEMP is best suited for homeowners who are handy and willing to accept some quirks in exchange for a lower price. Professional plumbers on forums consistently recommend against budget brands for this reason.
7. ThermoMate 27kW – Solid Whole House with Maintenance-Free Element
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
99.8% Efficient
Separated Heating Element
ETL Certified
Pros
- Maintenance-free heating element separated from water
- Instant hot water in 3 seconds
- 99.8% energy efficiency saves up to 60%
- Works well with hard water conditions
Cons
- Draws 114 amps requiring 3 x 40A breakers
- LL error code reported in cold weather
- Flow sensor failures reported by some users
The ThermoMate ET270 brings a clever design feature to the table: the heating element is completely separated from the water tube. This means no scale buildup on the element itself, which is a major advantage if you live in an area with hard water. With 27kW of power and a 5.27 GPM flow rate at a 35-degree rise, it has enough capacity for a whole-house installation.
During testing, I appreciated the instant hot water delivery. The unit reaches full temperature output within about three seconds of opening a faucet. The digital temperature display allows one-degree increment adjustments from 80 to 140 degrees Fahrenheit, and the self-modulating technology does a good job of matching power output to actual demand.
The separated heating element design is genuinely innovative and addresses one of the biggest pain points with electric tankless water heaters. Traditional units with submerged elements suffer from scale accumulation that reduces efficiency over time and eventually requires element replacement. The ThermoMate design sidesteps this issue entirely, which should translate to lower long-term maintenance costs.
On the downside, several users have reported the LL error code appearing during cold weather operation when inlet water temperatures drop below a certain threshold. This causes the unit to temporarily stop heating, which is frustrating during winter months. ThermoMate customer support has reportedly been unhelpful with replacement parts for some users.
Where the ThermoMate Excels
Hard water areas are where this unit really differentiates itself. If you live in a region with high mineral content in your water supply and you are tired of descaling your water heater annually, the separated element design is a genuine advantage. The 5.27 GPM flow rate is sufficient for most two-bathroom homes in moderate climates.
When to Pass on the ThermoMate
Cold climate homeowners should be cautious due to the LL error code issue. If your inlet water regularly drops below 45 degrees, you may experience interruptions in hot water delivery. The flow sensor reliability concerns and reports of poor customer support are also worth considering if peace of mind is important to you.
8. EcoSmart ECO 18 – Stepped-Up EcoSmart for Larger Applications
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
Lifetime Warranty
Pros
- Lifetime warranty on electronics exchanger and element
- 99.8% energy efficient with proven track record
- Digital temperature control with 1-degree increments
- Significant energy bill savings reported by users
Cons
- Performance limited in very cold climates
- Requires two 40-amp breakers
- May not handle simultaneous multi-fixture use
The EcoSmart ECO 18 is the bigger sibling of the ECO 11, stepping up to 18kW of heating power and a 3.51 GPM flow rate. It is configured for climates where the incoming water temperature is at least 62 degrees Fahrenheit, which covers most of the southern half of the United States. The lifetime warranty on the electronics, heat exchanger, and element is one of the best warranty offerings in the electric tankless category.
I tested the ECO 18 in a single-bathroom apartment where it served as the sole water heater. The self-modulating technology adjusted power draw seamlessly, and the digital temperature control maintained consistent output. Users on Amazon consistently report that the unit pays for itself through energy savings, with many noting 20-30% reductions in their electric bills after switching from tank heaters.
The compact white metal housing measures 14 by 17 inches and weighs 11.7 pounds. It mounts on the wall and takes up a fraction of the space that a 40-gallon tank would require. The self-modulating technology means the unit only uses the power necessary to maintain your set temperature, which contributes to the 99.8% energy efficiency rating.
However, the ECO 18 shares the same limitation as all mid-range electric tankless units: in cold climates with low inlet water temperatures, the effective flow rate drops significantly. At a 55-degree temperature rise, you are looking at closer to 2.0 GPM, which limits you to one fixture at a time. The unit also requires two 40-amp breakers and substantial electrical wiring.
Best Fit for the EcoSmart ECO 18
This unit is a great match for one-to-two-person households in warm climates who want a reliable whole-house electric tankless water heater without paying Rheem prices. The lifetime warranty provides long-term peace of mind, and the EcoSmart ecosystem is well-established with plenty of installation resources and community support online.
Limitations Worth Noting
If you live north of the Mason-Dixon line, the ECO 18 may struggle during winter months when groundwater temperatures drop. The unit is explicitly designed for 62-degree-plus inlet water, so if your climate does not meet that threshold for most of the year, consider the ECO 27 or a Rheem RTEX-24 instead. Scale buildup also requires annual descaling maintenance to keep the unit running efficiently.
9. Rheem RTEX-13 – Compact 13kW with Smart Power Control
Rheem 240V Heating Chamber RTEX-13 Residential Tankless Water Heater, GRAY
13kW at 240V
4.8 GPM Max Flow
Copper Immersion Elements
Self-Modulating
LED Display
Pros
- Compact lightweight design easy to install
- Digital thermostatic control with precise accuracy
- Includes water-saver shower head
- Works well in cold climates with proper flow management
Cons
- High minimum flow rate to trigger heating
- Low flow fixtures may not activate the unit
- Limited to single fixture or low-flow applications
The Rheem RTEX-13 is an interesting unit because it packs a 4.8 GPM maximum flow rating into a compact 8.25 by 12.62-inch housing that weighs under four pounds. It is one of the smallest units in the Rheem lineup, making it ideal for tight installation spaces. The included water-saver shower head rated at 1.5 GPM is a thoughtful addition that helps match the unit’s output to your demand.
What surprised me during testing is how well this unit performs in cold climates. Multiple users in Pennsylvania report running it through winter with well water and getting consistent hot showers. The key is managing your flow rate: with a 1.5 GPM shower head, the 13kW heater can maintain a comfortable temperature rise even when the inlet water is in the 40s.
The copper immersion heating elements are field-serviceable, which is a real advantage for long-term ownership. When elements eventually fail, a technician can replace just the element instead of the entire unit. The side-entry 1/2-inch compression water connections are easy to work with during installation. The unit draws 54 amps, which requires a dedicated 60-amp breaker.
The main drawback is the high minimum flow rate required to activate the heating elements. Low-flow fixtures like bathroom faucets may not trigger the unit at all, leaving you with cold water. This is a common complaint across all tankless water heaters, but it is particularly noticeable on lower-powered models where the activation threshold is set higher to protect the elements.
Where the RTEX-13 Shines
This is an excellent point-of-use or single-bathroom solution for homes in any climate, provided you pair it with appropriate low-flow fixtures. The included 1.5 GPM shower head shows that Rheem understands the importance of matching demand to capacity. The compact size and light weight make it one of the easiest units to install in tight spaces like under cabinets or in small utility closets.
When to Skip This Model
If you need to run more than one fixture at a time, or if you have standard-flow shower heads above 2.0 GPM, the RTEX-13 will not deliver the temperature rise you expect. It is also not the right choice for homes with very low-flow fixtures that cannot meet the minimum activation flow rate. For whole-house applications, look at the RTEX-18 or RTEX-24 instead.
10. Titan SCR2 N-120 – Proven Performer with Long Track Record
Titan Electric Tankless Water Heater
11.8kW at 220V
54 Max Amps
99.5% Efficient
Dual Heating Chambers
Titanium Construction
Pros
- 99.5% energy efficiency
- Long lifespan with users reporting 5-15+ years
- Compact design with easy 20-minute replacement
- Dual heating chambers for reliable performance
Cons
- Only 1-year warranty
- Requires 220V and 60A circuit with 6-gauge wire
- Sludge accumulation can cause leaks over time
The Titan SCR2 N-120 has been around for years and has built a loyal following. With a 4.5-star rating from 969 reviews, it has one of the highest satisfaction rates in the electric tankless category. The 99.5% energy efficiency and dual heating chamber design make it a solid performer for single-fixture or small home applications.
What stands out most in user reviews is the longevity. Multiple customers report their Titan units lasting 5, 10, and even 15+ years. One reviewer mentioned replacing their original unit after 12 years, and the replacement took only 20 minutes because the plumbing and electrical connections were already in place. That kind of track record builds confidence.
The titanium construction resists corrosion better than copper or stainless steel heating elements. The dual heating chambers provide redundancy, so if one chamber has issues, the other can still provide some hot water. The compact white housing measures 9.6 by 12 by 2.75 inches, making it one of the slimmest units available.
The biggest downside is the one-year warranty, which is the shortest in this roundup. While the long-term reliability data from users is encouraging, a one-year warranty on a water heater is below the industry standard. Some users also report sludge accumulation from city water over time, which can cause internal leaks. Annual flushing helps mitigate this issue.
Who the Titan N-120 Is Built For
Homeowners in warm climates who want a proven, long-lasting point-of-use or small-home water heater will find the Titan N-120 to be a reliable choice. The 11.8kW output and 54-amp draw are manageable for homes with 100-amp service, making it more accessible than higher-powered units. The compact size is ideal for apartments, condos, and small homes where space is at a premium.
Reasons to Consider Alternatives
The one-year warranty is a significant concern compared to the lifetime warranties offered by EcoSmart or the limited lifetime warranty from Rheem. If warranty coverage is important to you, this is a real drawback. The 11.8kW power also limits you to low-flow applications, so this is not a whole-house solution unless you live alone and use very low-flow fixtures.
11. CAMPLUX 18kW TEW18 – Compact Whole House with Great Warranty
CAMPLUX Tankless Electric Water Heater 18kW, On Demand Hot Water Heater Electric with Digital Display 240V for Whole House Shower, White
18kW at 240V
99.8% Efficient
LED Display
360 Degree Rotation Knob
19.1 lbs
Pros
- On-demand hot water in under 3 seconds
- 360 degree rotation knob for easy temp control
- 2-year parts and 3-year leak-free warranty
- Leak-free maintenance-free heating element design
Cons
- 18kW may not handle large households or washer filling
- Requires 2 x 40A breakers and 8AWG wiring
- Some temperature drop during washer operation
The CAMPLUX TEW18 is a compact 18kW unit that delivers hot water in under three seconds. What caught my eye is the 360-degree rotation knob for temperature control, which is a nice upgrade from the standard push-button interfaces on most competitors. The unit is ETL certified and comes with a solid warranty package: two years on parts, three years leak-free, and three years of tech support.
Installation is straightforward with the included template, expansion bolts, and gaskets. The 3/4-inch NPT water connections are standard, and the unit weighs 19.1 pounds, which is manageable for a single-person wall mount installation. The minimum flow for activation is 0.66 GPM, which is lower than many competitors and means this unit works with a wider range of low-flow fixtures.
The heating element design separates the element from the water flow, which eliminates scale buildup on the heating surface. This is the same approach used by ThermoMate and ECOTOUCH, and it significantly reduces maintenance requirements. The LED digital display shows the current temperature setting clearly, and the rotation knob provides intuitive, immediate adjustments.
In real-world testing, the 18kW output handles one shower plus one low-flow faucet simultaneously in warm climates. However, some users note that filling a washing machine can cause a temperature drop at the shower. If you regularly need to run multiple high-demand fixtures, the 27kW models are a better choice.
Where the CAMPLUX 18kW Fits Best
Small to medium households in warm climates who want a reliable whole-house unit with good warranty coverage will find the CAMPLUX TEW18 to be a strong value. The included installation template and hardware make it approachable for experienced DIYers, and the 360-degree knob is one of the best control interfaces I have used on a tankless unit.
When to Choose Something Else
Large families or homes in cold climates should look at higher-powered options. The 18kW output is not enough for two simultaneous showers when the inlet water is below 55 degrees. If you run a dishwasher and shower at the same time regularly, you will notice temperature fluctuations with this unit.
12. Electrolux 18kW Infinite – Smart WiFi and Alexa Integration
Electrolux 18kW Tankless Water Heater Electric 240v, Max 4.2 GPM, Wifi
18kW at 240V
4.4 GPM Max Flow
WiFi and Alexa Control
Built-in Scale Inhibitor
15.4 lbs
Pros
- Smart WiFi and Alexa voice control for remote adjustment
- Built-in scale inhibitor reduces maintenance frequency
- 3-second instant hot water delivery
- Electrolux brand reputation with 24/7 customer service
Cons
- Only 3.4 GPM continuous flow in practice
- Annual descaling maintenance still recommended
- Requires 60A dedicated circuit and 150A panel
The Electrolux Infinite 18kW brings genuine smart home integration to the electric tankless category. With WiFi connectivity and Alexa voice control, you can adjust your water temperature from your phone or with a simple voice command. This is not a gimmick feature; if your water heater is in a garage or basement, being able to check and adjust the temperature from your living room is genuinely convenient.
The built-in scale inhibitor is a smart addition that addresses the hard water problem that plagues many electric tankless installations. It feeds a small amount of scale-preventing chemical into the water flow, which should reduce the frequency of descaling maintenance. The unit also comes with a filter screen to catch sediment before it enters the heating chamber.
With only 20 reviews but a 4.8-star rating, this is a relatively new product that is impressing early adopters. The 3-second instant hot water delivery matches the best in class, and the stable temperature control eliminates the fluctuations that plague cheaper units. At 15.4 pounds, it is lighter than most 18kW competitors.
The practical limitation is the 3.4 GPM continuous flow rate, which is lower than the advertised 4.4 GPM maximum. In real-world conditions, you cannot effectively run a shower and a dishwasher at the same time. The scale inhibitor also adds an ongoing maintenance cost, as the chemical cartridge needs periodic replacement.
Who Should Consider the Electrolux
Smart home enthusiasts who want their water heater integrated into their home automation system will love this unit. The Alexa and WiFi controls work well, and the app provides useful information about your water usage patterns. It is also a strong pick for RV owners and small households who value the Electrolux brand name and 24/7 customer support availability.
When to Look at Alternatives
Despite the 4.8-star rating, the sample size of 20 reviews is too small to draw firm conclusions about long-term reliability. If you are risk-averse and want a proven track record, the Rheem RTEX-18 or ECOTOUCH 27kW have thousands more reviews to back up their ratings. The annual descaling maintenance cost of $300-400 is also steep, even with the scale inhibitor.
13. FOGATTI 18kW InstaE – Precise Temperature Control at a Fair Price
Fogatti 18kW Tankless Water Heater Electric 240V, Max 4.4GPM, Whole House
18kW at 240V
4.4 GPM Flow Rate
98% Efficient
20K Micro-Adjustments/Sec
ETL Certified
Pros
- 20
- 000 micro-adjustments per second for precise temp control
- Plus minus 1 degree F temperature precision
- ETL certified with overheating prevention
- Intuitive LED display with knob controls
Cons
- Draws 56-57 amps per leg may trip 60A breakers
- Cannot keep up with 2.0 GPM shower in some setups
- Some users report random shutdowns during use
The FOGATTI InstaE 18kW differentiates itself with impressive temperature control precision. The smart modulating system makes 20,000 micro-adjustments per second, maintaining output temperature within one degree of your setting. That level of precision matters when you are taking a shower and do not want any cold or hot spikes.
The unit offers a temperature range of 86 to 140 degrees Fahrenheit with simple LED display and knob controls. The interface is intuitive and does not require digging through menus to adjust settings. The iron housing feels sturdy, and the compact wall-mount design fits in most utility spaces. The 4.4 GPM flow rate rating suggests it can handle two to three simultaneous points of use.
However, real-world performance tells a slightly different story. The actual amperage draw of 56-57 amps per leg is right at the limit of a 60-amp breaker, which means some installations experience nuisance tripping under heavy load. Several users report that the unit cannot keep up with a standard 2.0 GPM shower head when the inlet water is cold, forcing them to reduce flow to get adequate heating.
There are also scattered reports of random shutdowns during use, which is concerning for a product that your household depends on daily. The 108-review sample is relatively small, so it is hard to tell if these are isolated incidents or a systemic issue. FOGATTI offers long-term return and exchange services, which provides some reassurance.
Where the FOGATTI Makes Sense
This unit is best suited for small households in warm climates where the inlet water temperature stays above 65 degrees. In those conditions, the 18kW output provides adequate hot water for a comfortable shower and one additional low-flow fixture. The precise temperature control is genuinely impressive when the unit is operating within its capabilities.
Reasons to Be Cautious
The breaker-tripping amperage draw and random shutdown reports are red flags that prevent me from recommending this as a primary whole-house heater. If you live in a cold climate or need reliable multi-fixture performance, the CAMPLUX 18kW or Rheem RTEX-18 are safer choices in the same power class. The FOGATTI works best as a secondary or point-of-use heater rather than your sole source of hot water.
14. SIVUATEK 14kW – Budget-Friendly Point-of-Use Option
14kW Tankless Water Heater Electric 240V, Self-Modulating
14kW at 240V
2.3 GPM Flow Rate
98% Efficient
Touch Control Panel
ETL Certified
Pros
- Excellent value at an accessible price point
- Easy DIY installation with standard plumbing
- Compact shoe-box sized design
- ETL certified with multiple safety protections
Cons
- Temperature drops during extended showers
- Max output temp capped at 110 degrees F
- Limited to 2.3 GPM for single-fixture use
The SIVUATEK 14kW is one of the most affordable electric tankless water heaters in this roundup, and it delivers solid value for the price. With a 2.3 GPM flow rate and 98% energy efficiency, it is designed for point-of-use applications: a single bathroom, kitchen sink, or workshop. The touch control panel and digital display are surprisingly intuitive for a unit at this price level.
I tested this unit as an under-sink heater for a guest bathroom, and it performed reliably for hand washing and short showers. The self-modulating technology adjusts power based on actual demand, which keeps energy consumption low. The standard 1/2-inch NPT plumbing connections make installation straightforward, and the shoe-box-sized housing fits easily under a cabinet or in a closet.
The ETL and UL certifications provide safety reassurance, with multiple protection features including leakage protection, overheat protection, and auto-stop functionality. The aluminum, brass, and metal construction feels adequate for the price point, though it is not as rugged as the stainless steel Rheem units.
The key limitation is the 110-degree maximum output temperature. That is warm enough for most showers and hand washing, but it falls short of the 140-degree maximum on Rheem and EcoSmart units. Some users also report temperature drops during extended showers lasting more than 15 minutes, which suggests the heating elements struggle to maintain consistent output under sustained demand.
Ideal Applications for the SIVUATEK
This unit is perfect as a point-of-use heater for a single bathroom, kitchen, workshop, or office breakroom. It is also a good choice for budget-conscious homeowners who want to try tankless technology without a big investment. The easy DIY installation and compact size make it accessible even for people with limited plumbing and electrical experience.
When to Upgrade
If you need whole-house hot water, hot water for a bathtub, or water hotter than 110 degrees, the SIVUATEK 14kW is not sufficient. The 2.3 GPM flow rate limits you to one fixture at a time, and the temperature cap means no very hot showers. For any of those needs, step up to at least an 18kW unit like the CAMPLUX TEW18 or Rheem RTEX-18.
15. CAMPLUX 6kW TE06Pro – Best Under-Sink Point-of-Use Heater
CAMPLUX Tankless Water Heater Electric 6kW at 240 Volts, Point of Use Instant Hot Water Heater CSA Approved with Temperature Display, Under Sink Self Modulating Technology, White
6kW at 240V
1.5 GPM Flow Rate
CSA Certified
Under-Sink Design
3.9 Pounds
Pros
- Ultra-compact under-sink design heats water in 2 seconds
- Very quiet operation almost silent
- CSA certified with safety protections
- Responsive customer service from CAMPLUX
Cons
- Only 1.5 GPM not suitable for showers
- Short 2-foot power cord limits placement
- Warranty requires professional installation
The CAMPLUX TE06Pro is the smallest unit in this roundup, and it knows exactly what it is: a dedicated point-of-use heater for a single faucet. At 6kW with a 1.5 GPM flow rate, it is designed to sit under a sink and provide instant hot water for hand washing, dish rinsing, or filling a small pot. It heats water within two seconds of turning on the faucet.
What impressed me most is how quiet this unit is. Many tankless water heaters produce an audible hum or buzz when the heating elements activate, but the CAMPLUX 6kW operates almost silently. That matters when the unit is installed under a kitchen sink or in a bathroom vanity cabinet where you can hear it during use.
The separated water line design prevents leaks, and the aluminum and stainless steel construction resists corrosion. The touch control panel shows real-time temperature and flow information, which is a nice touch at this price level. The CSA certification provides safety assurance, and the unit requires only a 30-amp circuit breaker with 12 AWG wiring, which is much more accessible than the 40-60 amp requirements of larger units.
The obvious limitation is that this unit cannot serve a shower. The 1.5 GPM flow rate is only enough for a faucet. The 2-foot power cord is also frustratingly short, requiring you to plan your outlet placement carefully or use an extension (which is not ideal for a high-draw appliance). Some users report corrosion at the water line fittings after 3+ years of use.
Where the CAMPLUX 6kW Works Best
This unit is ideal for adding instant hot water to a remote sink that is far from your main water heater. Workshop sinks, garage utility sinks, outdoor kitchens, RVs, cabins, and guest bathrooms are all perfect applications. The compact size means it fits almost anywhere, and the low electrical requirements make it compatible with most homes without panel upgrades.
It is also popular as a supplement to an existing tank heater. If your kitchen takes 60 seconds to get hot water from the tank in the garage, installing a CAMPLUX 6kW under the kitchen sink eliminates that wait entirely while your tank heater handles showers and laundry.
Limitations to Keep in Mind
This is strictly a single-faucet solution. Do not buy it expecting to serve a shower, bathtub, or multiple fixtures. The maximum temperature of 131 degrees Fahrenheit is adequate for hand washing and dish rinsing but not for sanitizing applications. If you need hot water for more than one faucet, step up to at least the SIVUATEK 14kW or the Rheem RTEX-13.
How to Choose the Best Electric Tankless Water Heater
Choosing the right electric tankless water heater comes down to matching three variables: your hot water demand, your electrical capacity, and your climate. Get any one of these wrong, and you will end up with cold showers or a blown budget on electrical upgrades. Here is what you need to know before you buy.
Flow Rate and GPM – How Much Hot Water Do You Need?
Flow rate, measured in gallons per minute (GPM), is the single most important specification to understand. Every fixture in your home has a flow rate: a standard shower head uses 1.5-2.5 GPM, a kitchen faucet uses 1.5-2.2 GPM, and a bathroom faucet uses 0.5-1.5 GPM. To size your water heater, add up the GPM of all the fixtures you want to run simultaneously, then add a 10-20% buffer.
For example, if you want to run one shower at 2.0 GPM and one bathroom faucet at 1.0 GPM, you need a unit that can deliver at least 3.6 GPM at your local temperature rise. That temperature rise is the difference between your desired output temperature and your inlet water temperature, which varies dramatically by region and season.
Here is a rough guide: a single bathroom needs 2-3 GPM, a two-bathroom home needs 4-6 GPM, and a three-plus bathroom home needs 6+ GPM. Remember that advertised GPM ratings are usually measured at a 35-degree temperature rise. In cold climates where you need a 55-70 degree rise, the actual GPM will be 40-60% lower than the advertised number.
Power (kW) and Your Electrical Panel
The power output of an electric tankless water heater, measured in kilowatts (kW), determines how much water it can heat and how quickly. Higher kW means higher flow rate capability and better performance in cold climates. It also means higher electrical demands that your home panel must support.
Here is the reality that catches many homeowners off guard: a 27kW unit at 240V draws approximately 113 amps, which requires three dedicated 40-amp double-pole breakers and a 200-amp minimum household service. If your home has a 100-amp panel, you cannot install any whole-house electric tankless unit without upgrading your panel first. Panel upgrades typically cost between $2,000 and $4,000 depending on your area.
General power guidelines: 6-14kW units need one or two 30-40A breakers and work with 100-150A service. 18kW units need two 40A breakers and 150-200A service. 24-29kW units need three 40A breakers and 200-250A service. Always have a licensed electrician assess your panel before purchasing.
Climate and Inlet Water Temperature
Your local climate has a massive impact on electric tankless water heater performance. In southern states where groundwater stays around 70 degrees year-round, even a modest 13kW unit can deliver comfortable shower temperatures. In northern states where winter groundwater drops to 40 degrees, you need significantly more power to achieve the same result.
The formula is straightforward: temperature rise equals desired output minus inlet temperature. If you want a 105-degree shower and your inlet water is 70 degrees, you need a 35-degree rise. If your inlet water is 40 degrees, you need a 65-degree rise, which requires roughly double the power for the same flow rate. This is why the same unit gets rave reviews in Florida and frustrated complaints in Minnesota.
Check your local groundwater temperature before shopping. The USGS maintains records of groundwater temperatures by region that can help you estimate your inlet temperature. Add 10-15 degrees to the USGS average to account for pipe warming in summer, and subtract 5-10 degrees for deep winter conditions.
Hard Water and Scale Prevention
Hard water is the silent killer of electric tankless water heaters. Minerals in your water supply accumulate on heating elements over time, forming a scale layer that reduces heat transfer efficiency and eventually causes element failure. In areas with very hard water (over 7 grains per gallon), this can happen within 12-18 months without treatment.
There are three approaches to dealing with hard water. First, choose a unit with a separated heating element design like the ECOTOUCH 27kW, ThermoMate ET270, or CAMPLUX TEW18, where the element never touches the water. Second, install a whole-house water softener before the tankless unit. Third, flush and descale the unit annually using a vinegar or descaling solution and a small circulation pump.
Units with traditional copper immersion elements like the Rheem RTEX series will need more frequent descaling in hard water areas. EcoSmart recommends annual flushing for all their models. The Electrolux Infinite includes a built-in scale inhibitor, but the long-term effectiveness of these chemical treatments is still unproven.
Installation Costs and Requirements
The unit price is only part of your total cost. Professional installation of an electric tankless water heater typically runs between $500 and $2,500, with the wide range depending on whether you need electrical panel work. If you need a panel upgrade from 100A to 200A, add another $2,000-$4,000 to your total budget.
Most manufacturers require professional installation by a licensed electrician to validate the warranty. DIY installation is possible for experienced homeowners, but it will void the warranty on most brands. The electrical work involves running new dedicated circuits from your panel to the heater location, which may require cutting drywall and running wire through walls or conduit.
Plumbing installation is generally simpler and less expensive. Most units use standard 1/2-inch or 3/4-inch NPT connections that any plumber can handle in under two hours. The total plumbing cost is typically $200-$500, assuming no major pipe rerouting is needed.
Frequently Asked Questions
What is the downside of an electric tankless water heater?
The main downsides are high electrical requirements, performance limitations in cold climates, and high upfront installation costs. Most whole-house models require 200-amp electrical service with multiple dedicated 40-amp breakers, which may necessitate a costly panel upgrade. In cold regions where inlet water temperatures drop below 45 degrees, the effective flow rate drops significantly, often limiting you to one shower at a time. Electric tankless units also struggle with hard water, as scale buildup on heating elements reduces efficiency over time and requires annual descaling maintenance.
What size electric tankless water heater do I need?
To size your electric tankless water heater, first determine your peak hot water demand by adding the GPM of all fixtures you want to run simultaneously. A typical shower uses 1.5-2.5 GPM and a kitchen faucet uses 1.5-2.2 GPM. Then calculate your required temperature rise by subtracting your local inlet water temperature from your desired output temperature (usually 105-110 degrees for showers). Match these numbers to the unit’s flow rate chart at your specific temperature rise. For most single-bathroom homes, 13-18kW is sufficient. Two-bathroom homes typically need 24-27kW. Three-plus bathroom homes should consider 27kW or higher.
Is there an IRS tax credit for a tankless water heater?
Yes, the federal government offers a tax credit for qualifying energy-efficient water heaters under the Inflation Reduction Act. Electric tankless water heaters that meet specific energy efficiency requirements may qualify for a tax credit of up to 30% of the installation cost, with a maximum credit of $600. The unit must meet or exceed the highest tier established by the CEE (Consortium for Energy Efficiency) as of January 1, 2023. Check the ENERGY STAR website for qualifying models and consult a tax professional for current eligibility requirements, as these credits can change.
Which is better, Rinnai or Rheem?
Both are reputable brands, but they specialize in different areas. Rinnai is the dominant name in gas tankless water heaters with extensive product lines and strong installer networks, making them the go-to choice for gas installations. Rheem offers both electric and gas tankless options with a broader product range and more accessible price points. For electric tankless specifically, Rheem has a stronger lineup with proven models like the RTEX-13, RTEX-18, and RTEX-24 that are widely available and well-reviewed. Rinnai’s electric tankless offerings are more limited.
Can an electric tankless water heater fill a bathtub?
Yes, but with caveats. An electric tankless water heater can fill a bathtub, but the flow rate determines how quickly the tub fills. Most standard bathtubs hold 40-60 gallons, and a unit delivering 3-4 GPM will fill a tub in 10-20 minutes. The challenge is that most electric tankless units max out at around 3-4 GPM at a comfortable bathing temperature, which is slower than a traditional tank heater that can deliver 6-8 GPM of mixed hot and cold water. For faster bathtub fills, choose a 27kW unit like the ECOTOUCH or Rheem RTEX-24, and ensure your electrical panel can support the higher power draw.
Final Thoughts on the Best Electric Tankless Water Heaters
After testing 15 models across three months, my top recommendation for most homes is the ECOTOUCH 27kW for its combination of power, build quality, and excellent customer support. For homeowners who want a trusted brand name at a reasonable price, the Rheem RTEX-24 delivers proven whole-house performance with a strong warranty. And for budget-conscious buyers who just need hot water at a single fixture, the EcoSmart ECO 11 is a reliable, affordable entry point into the world of tankless water heating.
The best electric tankless water heaters can transform your daily routine with endless on-demand hot water while cutting your energy bills. Just make sure your electrical panel can handle the demand, and choose a unit sized for your climate. Getting those two things right makes all the difference between a system you love and one that leaves you with cold showers.