Our Top Picks
- Flow rate of 4.4 GPM
- Easily replaceable parts
- Sleek metal design
- Handles 37 degree inlet water
- 27 kW of whole-home power
- Digital control in 1 degree steps
- Compact 10.9-inch body
- CSA-approved safety
- 0.4 GPM low-flow activation
Our Review Criteria: Flow rate only means something when it is sized against real groundwater temperature, so that pairing led our comparison of electric tankless heaters. We weighed the electrical service each unit demands, its temperature range, and its warranty, following ENERGY STAR and Department of Energy sizing guidance. We checked each manufacturer’s published figures against verified owner feedback. We confirm every pick is currently sold and in stock and swap out any model that goes out of production.
Running out of hot water halfway through a shower ranks high on the list of small daily miseries. If you are tired of fighting over the last warm gallon, an electric tankless water heater solves it at the source.
These units heat water on demand, which saves energy, frees up closet space, and eventually reduces your utility bills. However, shifting from a traditional tank to a tankless system requires the right knowledge, especially regarding electrical requirements.
To help you navigate the options, we researched the market to find the most reliable models available. Here are our top picks for the best electric tankless water heaters to keep your showers warm and your energy usage low.
Types of Electric Tankless Water Heaters
Selecting the right heater isn’t just about picking the highest rating. You need a unit that matches your specific lifestyle and plumbing setup. Whether you are camping off-grid or renovating a family home, there is a specialized unit for the job.
We broke down the three main categories to help you identify which style fits your needs.
Portable heaters are the ultimate travel companion. If you love festivals, camping, or staying at RV parks, these units ensure you can scrub off the dirt with a warm shower. Most kits come with a showerhead attachment included.
You simply plug them into a standard outlet or connect them to a vehicle battery.
Pros
- Space-saving design: These units are lightweight and compact, so you can toss them in the trunk and store them easily when you get home.
- Weather protection: Manufacturers build these for the outdoors. Many feature freeze protection or durable casings to handle temperature drops.
- Safety features: Since you move these around, they often include tilt-switches that shut the unit off if it falls over, as well as auto-shutoff timers.
Cons
- Power limitations: You may need to connect to a car battery or specific power source, which requires preparation before your trip.
These small units fit directly inside cabinets or under sinks. They are designed to boost temperature for a single faucet or a distant bathroom that takes too long to get hot water from the main tank.
If you wash dishes and run out of hot water, or just hate waiting for the tap to warm up, this is your solution.
Pros
- Budget-friendly: These are significantly cheaper than whole-home systems and use less energy since they only heat water for one specific fixture.
- Instant results: Because the heater is inches away from the faucet, you get hot water immediately without the wait.
- Efficiency: You eliminate the heat loss that occurs as water travels through long pipes in your house.
Cons
- Limited capacity: These cannot run a shower or supply a whole house. They are strictly for sinks or single low-flow appliances.
Whole-Home Electric Tankless Water Heaters
This is the focus of our reviews below. These powerful units replace your old 40 or 50-gallon tank. Provided you choose one with the right Gallons Per Minute (GPM) rating, they can supply endless hot water to showers and sinks simultaneously.
Pros
- Long-term savings: While electricity costs vary, these units eliminate “standby loss” because they do not keep a tank of water hot 24/7.
- Eco-friendly: They only consume significant power when you turn the tap on.
- Hygiene: You get fresh water instantly rather than using water that has been sitting in a rusty tank.
Cons
- Initial investment: The unit cost and the potential need for electrical panel upgrades make these more expensive upfront than tank heaters.
Things to Consider: Buying Guide
Before you buy, you need to understand the specs. Buying the wrong size is the most common mistake homeowners make with tankless systems. Here is what you need to look for.
Durability and Materials
Look for internal components made of copper or stainless steel. These materials resist corrosion and transfer heat efficiently. High-quality heating elements ensure you won’t be taking cold showers a few years down the road.
Some modern units feature digital displays and modulation technology, which extends the lifespan of the unit by preventing it from working harder than necessary.
Product Reviews
We compared flow rates, power requirements, and reliability to bring you these top five recommendations.
Rheem RTEX-18 Residential Tankless Water Heater
Easiest to Install
The Rheem RTEX-18 balances power and usability perfectly. It sits in the “sweet spot” of the market, powerful enough for small-to-medium homes (up to 4.4 GPM) but easier to manage electrically than the massive units.
It features an external digital thermostatic control with an LED display, making it incredibly easy to set your exact preferred temperature. The heating elements are durable copper immersion types, which are field-serviceable.
What We Like
Great for Medium Homes
This 18kW unit handles everyday tasks with ease. It can support one shower and one sink simultaneously in colder climates, or two showers in warmer southern states.
Easy Installation
The unit comes with 3/4 inch NPT water connections on the bottom and allows for simple electrical hookups. It’s a favorite among DIY-savvy homeowners because the instructions are clear and the form factor is manageable.
Durable Components
Rheem uses two copper immersion heating elements. Copper is excellent for heat transfer and durability. Plus, if an element ever fails, you can replace just that part rather than the entire unit.
What We Don't Like
Standard Warranty
The warranty is decent but not industry-leading. You get 5 years on the heating chamber and 1 year on parts. Given the repairability of the unit, this is acceptable, but less generous than EcoSmart.
Product Specs
| Dimensions | 4 inches by 15 inches by 19 inches |
|---|---|
| Weight | 8.5 pounds |
| Flow Rate (Gallons Per Minute) | 4.4 GPM |
| Activation Flow | 0.3 GPM |
| Output Temperature Range | 59 to 140 degrees Fahrenheit |
| Volts Required | 240 |
Stiebel Eltron Tempra 36 Plus Tankless Water Heater
Highest Flow Rate
The Stiebel Eltron Tempra 36 Plus is the most powerful unit in this roundup. At 36kW it delivers up to 7.03 GPM, enough to run two showers and a sink at once even where the groundwater runs cold. This is the heater for a large household that refuses to ration hot water.
It pairs German engineering with Advanced Flow Control and a digital display for dialing in the exact temperature. The trade-off is electrical: it draws 150 amps and wants a 300-amp household service, so it belongs in homes that can feed it.
What We Like
Highest Flow in the Group
With up to 7.03 GPM on tap, the Tempra 36 Plus outpaces every other heater here. It comfortably supplies a busy three or four bathroom home, even in northern winters where a smaller unit would turn lukewarm.
Advanced Flow Control
If demand briefly exceeds capacity, the unit trims the flow a touch to hold your set temperature instead of sending a cold slug down the line. That ends the cold water sandwich that plagues weaker tankless heaters.
Quiet and Efficient
Self-modulation matches the power draw to the moment, so you only pay for the heat you use, and the heater stays close to silent in a utility room or basement.
What We Don't Like
Demands Serious Power
Three 50-amp double-pole breakers and a recommended 300-amp service put this unit out of reach for many older panels. Budget for an electrician, and possibly a panel upgrade, before you buy.
Product Specs
| Dimensions | 16.6 inches by 14.5 inches by 4.6 inches |
|---|---|
| Weight | 19 pounds |
| Flow Rate (Gallons Per Minute) | 7.03 GPM |
| Activation Flow | 0.77 GPM |
| Output Temperature Range | 86 to 140 degrees Fahrenheit |
| Volts Required | 240 |
EcoSmart ECO 27 Electric Tankless Water Heater
Best For Cold Climates
The EcoSmart ECO 27 is the unit to look at if your groundwater runs cold. EcoSmart configures it for incoming water as low as 37 degrees Fahrenheit, which is the situation that defeats most electric tankless heaters in northern homes.
It draws 27kW at 240 volts and uses patented self-modulating technology, so it only pulls the power the current flow and temperature actually need. Output lands between roughly 2.7 and 6.5 GPM depending on how cold the inlet water is, which is enough for a shower and a sink together in most of the country, and close to 3 GPM in the depths of a northern winter.
The trade-off is the electrical service. This is not a unit you slot into an old panel without checking the numbers first.
What We Like
Built For Cold Groundwater
The ECO 27 is rated for inlet water down to 37 degrees. Southern-configured heaters lose most of their advertised flow when the ground gets that cold, so this rating matters more than a headline GPM figure.
Precise Digital Control
The thermostat adjusts in 1 degree increments across an 80 to 140 degree range. You can dial in a shower temperature and leave it there rather than fiddling with the mixer every time.
Slim Wall Footprint
At 3.5 inches deep, it hangs flat against a wall where a 50 gallon tank used to stand. The floor space you get back is usually the whole reason people go tankless.
What We Don't Like
Serious Electrical Demand
At 112.5 amps, the ECO 27 needs three dedicated 40 amp double-pole breakers, 8 gauge copper wire, and a panel with room to spare. Budget for an electrician, and confirm your service can carry it before you order.
Product Specs
| Dimensions | 17 inches by 17 inches by 3.5 inches |
|---|---|
| Weight | About 11 pounds |
| Flow Rate (Gallons Per Minute) | 2.7 to 6.5 GPM |
| Activation Flow | 0.3 GPM |
| Minimum Inlet Temperature | 37 degrees Fahrenheit |
| Volts Required | 240 |
Camplux TE06Pro Point-of-Use Water Heater
Best Low-Cost Water Heater
The Camplux TE06Pro proves you do not need to spend a fortune for instant hot water at the sink. As the budget pick in this roundup, this 6kW unit mounts under a single faucet to wash hands, rinse dishes, or warm a far-off bathroom tap that the main heater takes too long to reach.
A digital touch panel shows the live water temperature, and the unit only fires when you open the tap, so it sips power compared to a small storage tank. It is CSA approved and uses self-modulating technology to hold a steady output.
What We Like
Tiny Footprint
At 10.9 by 7.08 by 2.5 inches and just 5.21 pounds, it tucks inside a vanity cabinet with room to spare for your cleaning supplies.
Low-Flow Activation
It starts heating at only 0.4 GPM, so even a gentle trickle at the faucet runs warm instead of waiting on the main tank across the house.
Safety Built In
The unit runs at 240 volts with over-temperature protection and a sealed design that keeps the water and electrical paths apart.
Simple to Wire
It needs one 30-amp breaker and 12-gauge wire, a far lighter load than any whole-home unit, so a point-of-use install stays manageable.
What We Don't Like
Strictly for Sinks
At 6kW and up to 1.5 GPM, this is not a shower heater. Camplux rates it for a single sink or low-flow fixture, not bathing. It also has to be hardwired, with no plug.
Product Specs
| Dimensions | 10.9 inches by 7.08 inches by 2.5 inches |
|---|---|
| Weight | 5.21 pounds |
| Flow Rate (Gallons Per Minute) | 1.5 GPM |
| Activation Flow | 0.4 GPM |
| Output Temperature Range | 85 to 131 degrees Fahrenheit |
| Volts Required | 240 |
Eemax EEM24018 Electric Tankless Water Heater
Most Aesthetically Pleasing
The Eemax EEM24018 is functionally very similar to the Rheem unit above (18kW) but comes in a distinct blue housing. It is a solid mid-range choice for families who need reliable hot water without a massive industrial-sized unit.
It requires two 40-amp breakers and delivers enough hot water for a 2-bathroom home in warm climates or a 1-bathroom home in colder areas. The self-modulating technology ensures it only draws the power necessary to heat the water to your set temperature.
What We Like
Stylish Design
While performance is king, looks matter. The bold blue casing adds a bit of flair to a utility room or garage. It looks modern and clean.
Consistent Performance
With a max flow of around 3.5 to 4 GPM (depending on conditions), it handles typical household loads well. It is an excellent choice for a washing machine or dishwasher supply, or for a standard family shower.
Simple Maintenance
Like its counterparts, it uses standard connections and accessible internal components. This makes flushing the system (to remove scale) or replacing sensors straightforward.
What We Don't Like
Cold Weather Limitations
In freezing winters where inlet water temperature drops significantly, this 18kW unit will struggle to run multiple fixtures. It is best suited for climates where the groundwater doesn’t get frigid, or for smaller households.
Product Specs
| Dimensions | 17 inches by 14 inches by 3.8 inches |
|---|---|
| Weight | 14.5 pounds |
| Flow Rate (Gallons Per Minute) | 3.5 GPM |
| Activation Flow | 0.5 GPM |
| Input Temperature Range | 55 to 105 degrees Fahrenheit |
| Volts Required | 240 |
| Product | Award | Dimensions | Weight | Flow Rate | Activation Flow | Input Temp. | Voltage |
|---|---|---|---|---|---|---|---|
| Rheem RTEX-18 | Easy To Install | 4″ x 15″ x 19″ | 8.5 lbs | 4.4 GPM | 0.3 GPM | 59 – 140 F | 240 V |
| Stiebel Eltron Tempra 36 | High Flow Rate | 16.6″ x 14.5″ x 4.6″ | 19 lbs | 7.03 GPM | 0.77 GPM | 86 – 140 F | 240 V |
| EcoSmart ECO 27 | Cold Climates | 17″ x 17″ x 3.5″ | 11 lbs | 2.7 – 6.5 GPM | 0.3 GPM | 37 F and up | 240 V |
| Camplux TE06Pro | Low-Cost | 10.9″ x 7.08″ x 2.5″ | 5.21 lbs | 1.5 GPM | 0.4 GPM | 85 – 131 F | 240 V |
| Eemax EEM24018 | Aesthetically Pleasing | 17″ x 14″ x 3.8″ | 14.5 lbs | 3.5 GPM | 0.5 GPM | 55 – 105 F | 240 V |
