Today:16 July, 2024

5 Best electric tankless water heaters

Time and time again, electricity is providing us with solutions to our slow running gas machine problems. This is no less the case for the water heater. In fact, you might say the best electric tankless water heaters solve all of the problems. It is more energy-efficient, cheaper to install and run, better for the environment, has a longer lifespan and they provide you with an endless supply of hot water.

However, there are a few factors that need considering when looking at electric tankless water heater reviews. The following is a simple but comprehensive rundown of review comparisons. So if you want to make sure you can jump into that nice warm shower whenever the wind takes you or wash your dishes all day long, be sure to read on.

Best electric tankless water heaters in 2022

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Electric tankless water heater reviews

Ecosmart 11 – A whole house electric tankless water heater

 EcoSmart ECO 11 Electric Tankless Water Heater

  • Whole house coverage
  • Lifetime warranty
  • Self-modulating technology
  • Digital display and temperature control via dial
  • 99.8% energy efficiency

The purpose of an electric water heater is that it is more energy efficient than gas, which means more money saved on your water bill, and more time. Ecosmart gets its name for precisely this reason. Its smart technology ensures that the unit has an energy efficiency rate of 99.8% and still heats up your water to optimal temperatures as soon as you want it. You won’t have to wait forever as you do with a tank water heater. Just turn it on and there your preferred temperature comes gushing out immediately.

In addition to this, the Ecosmart boasts a very attractive flow rate of 2.0 GPM. IT also has a great warranty and innovative ergonomic design. Keeping all this in mind and given its value for money, we would say this is the best electric tankless water heater for many homes.

Lifetime warranty

So, we’re saying this is one of the most powerful heaters and there’s an everlasting promise of a free replacement? This cannot be! But it is. It’s not often you get this lucky. A lifetime warranty is a sign of a successful company with a good reputation. You should be able to rely on this machine lasting a very long time, otherwise, the company would surely stand to lose a lot of money.

High flow rate

The more gallons powered per minute, the more water appliances can run at any one time, for longer. Ecosmart’s 2 gallons per minute flow rate is enough to cover the whole house for those living in warmer climates. In colder climates (below 67°F incoming water temperature), you may struggle to get many appliances running at the same time at your desired temperature. All you would need to do though is turn the temperature setting down or make sure you don’t clash your showering schedule with anyone’s laundry schedule.

Digital display

A digital display allows you to adjust the output temperature more precisely with the use of a dial. For this heater, you can set it at increments of 1°F. That’s great for when you like your shower not too hot, not too cold but just right in the middle somewhere.

Energy efficient smart design

The manufacturer tells us you could save up to 60% on your water bills with the Ecosmart. The heater then essentially pays for itself in under a year. Somewhat intelligently, the heater knows not to turn on unless you have turned on a water outlet. Amazingly, it also ignores faucet dripping, which can lead to huge savings if there is a leak or a loose tap.

The Good:

  • Saves a lot on bills
  • High flow rate for a single point of use heater
  • Lifetime warranty
  • Only turns on when water does

The Bad:

  • Expensive installation by a plumber
  • In colder climates, you may need to reduce water flow to get the same temperature

Rheem RTEX-13

Rheem tankless water heater reviews

  • Single point of use
  • 99.8% energy efficient
  • Two heating elements
  • Digital temperature display

The Rheem RTEX -13 is relatively small and super-efficient. Though users report it is mostly only suitable for a single point of use, it really depends on the climate you live in. In warmer climates, it can max out at a 4.8 GPM which could power multiple faucets in a small apartment. However, on average its output is 1.5 GPM, suitable for 1 shower and 2 faucets in one room. It would be very appropriate for places like an RV, a small shop or garage.

Simple installation

Once you have bought your water heater and the day finally comes for it to arrive, you may then realize you don’t know anything about how the thing works or even where to put it. With the Rheem water heater, this is not something you need to worry about as it is very simple to install and comes with all the things you need to install it. That also means no need to spend extra money on a plumber or electrician.

Single point of use water heater

Unfortunately, this unit is more suited for use in only one place, for one to three faucets. You’ll find this is the case for a lot of electric water temperature heaters with lower flow rates. Especially in colder climates, as you’ll have to heat up water that is already pretty cold which takes more power and more energy. You might get away with using it for multiple faucets near each other though if you live in a warmer climate. This would be suitable then if you live in a small apartment.

Heating elements

The RTEX-13 has long-lasting copper immersion two heating elements. Maybe you are not sure what that is. It doesn’t matter, the important thing is that this helps to ensure your water is heated instantly. You don’t even have to wait a minute, which honestly wouldn’t be that much of a bother but it’s always nice to save a little more time.

Energy efficiency

Rheem tankless water heater reviews and users alike swear by how much this one saves on the water bill. The word is that it can save 30% or more while still providing that instant hot water fix you need. This is exactly the reason why the tankless water heater has become so popular because you’re not wasting that huge big tank of water, which also wastes a lot of space, but just heating the water you’re using directly.

The Good:

  • Simple do it yourself installation
  • Heats up water instantly
  • Saves a lot on bills

The Bad:

  • Can only be used in one room
  • Flow rate not that high


 ECOTOUCH Electric Tankless Water Heater

  • Single point of use
  • Smart self adjustment of power input
  • Digital display and touch control
  • Small and sleek design
  • Multiple protection measures

ECOTOUCH is another one of those ECOnomical heaters. It is of course partly a branding technique to use the term ‘ECO’ in the name but in all honesty they’re not wrong to. This one saves not quite as much as our first two listings but still amounts to a 98% energy efficiency, saving a significant amount on your bills. It does this via a smart modulated temperature control that reacts in real time to waterflow level.

It is another one of those single points of use water heaters with a 1.5 GPM though, so make sure not to buy this if you’re looking to cover more than two to four faucets, depending on climate.

This is also the smallest water heater on our list and its design isn’t too shabby either. So it can really be placed anywhere without becoming an eyesore as many older models do.

Smart self-adjustment

Probably its finest feature is its intelligence. The heater device can calculate the exact amount of power input it needs according to the change in flow rate, so the temperature stays the same regardless of how much is coming from the tap. You can also adjust the temperature yourself on the heater within a range of 70°F to 131°F. The heater is not maxing out at 131°F because it cannot physically go any higher but for safety reasons, so you don’t scald yourself on the water.

Small and sleek

The dimensions of the ECOTOUCH are 11” x7.5” x 2.35” which means if you really didn’t want anyone to know you owned a water heater you could hide it under the sink easily. However, with its modern, sleek and shiny design, you may just want to show it off anyway. The smaller size also gives you more versatility as to where you can put it, as long as it’s near the faucet. This makes it ideal for a bar, a hospital, a classroom sink or maybe a hair salon.

Digital display and touch control

For some, this feature won’t make that much of a difference. The touch control panel though is smooth and easy to use and the sleek design will blend with the room’s surrounding décor. You can also precisely set your temperature in increments of 1°F.

Water and electricity line separated

The heater also comes with a lot of protection innovations. Firstly the water and electricity pipes are well separated which avoids any calcium deposit build up or leakage. Normal water heaters always had issues with this, as water builds up in the tank, so can bacteria and rust. Additionally, the ECOTOUCH features dry heating protection, over temperature protection and leakage protection. Hopefully, this all means a more durable and long lasting heater.

The Good:

  • Small and looks good
  • Constant temperature regulation via smart adjustment
  • Durable due to protective innovations
  • Economical and energy efficient

The Bad:

  • Can only be used in one room
  • Relatively small flow rate

Stiebel Eltron 24 Plus Tempra – A whole house electric tankless water heater

Stiebel Eltron Water Heater

  • Whole house coverage
  • High flow rate
  • Steel casing
  • Advanced flow control
  • Digital display
  • Silent operation

Stiebel Eltron has become a household name and the 24 Plus Tempra does not disappoint in its ability to heat a whole house full of water outlets. This heater tops our list as the most powerful, being that it has an amazing flow rate of 5.5 GPM! Of course, you will have to pay a lot more for the product for this precise reason.

You are paying as well for the wonderful freedom of having hot water on demand, as well as energy efficiency, durability, and smart temperature modulating. Price tag ignored, this one comes out as the best electric tankless water heater.

Efficient performance

The 5.5 GPM ensures that this water heater will work in both cold and warm climates for homes with two bathrooms. Compared to a regular water heater with a tank, you are looking at a 20-30% reduction in energy consumption and a total energy efficiency of 99%. That’s speed, power and money saved all rolled into one.

Durable materials

The materials used to make a tankless water heater also are innovative and much more durable than those used for the conventional tank water heaters. The Stiebel Eltron 24 Plus has a steel casing that is pretty heavy duty and therefore bolsters its sturdiness, while also giving it an attractive finish. Furthermore, it has a copper-sheathed heating element with a copper cylinder which aids greater water heating efficiency.

Silent operation

If you are planning to use this in your place of work where there may be customers, like a shop or hair salon, any sort of noise is likely to put off customers. Even for personal use, a heater that makes noise is not just off-putting but makes it feel cheap or makes you wonder if it’s faulty. It’s not like there’s an engine in there, you just want your water to be heated. So the silent operation of the Stiebel Eltron certainly signals a more advanced and developed design.

Advanced flow control

This is an industry-unique feature which automatically reduces the flow if the hot water demand exceeds capacity, in order for it to remain at constant temperatures. This specifically, results in longer shower time! It’s the worst when you’re half way through shampooing and you have to jump out because there’s no more hot water. This feature is great for those who like to have eternal showers without thinking about the time passing.

The Good:

  • Very high flow rate
  • Can be used for a whole house
  • Water remains hot for a long time
  • Silent
  • Durable and long lasting

The Bad:

  • Expensive
  • Needs a lot of power to keep it going


Bosch tankless water heater reviews

  • Single point of use
  • Series of 4 models with different power inputs and flow rates
  • Lightweight and small

The Bosch tankless water heater, Tronic 3000 series are a small bunch of heaters that are known as the point-of-use series. This implies that they are usually good for heating water to one fixture. It is an under-the-sink type. The tankless technology always delivers the on-demand water you’re looking for and they work with a decent, though not chart-topping, 98% efficiency.

The series is made up of 4 models, all with kW input and flow rate capabilities. Just have a look at the Bosch tankless water heater reviews and capabilities below and you can pick which one best suits your situation and how high of a flow rate you require.

4 different models-reviews and flow rates

Each model is appropriate for different situations and requirements. In warmer climates (necessitating a 45°F rise), the US3 model has a GPM output of 0.5, for the US7 it is 1.1, for US9 1.4 and for US12 it is 1.8. In climates where the water needs to be heated by 75°F, all of these GPMs decrease by a bit more than a 3rd.

The price increase for GPM is not much and the size of each model stays the same. Most of these GPMs are suitable for one or two faucets at a single point of use. The US9 and US12 could facilitate the use of three or four faucets at the same time though. With the US12, in warmer climates, you may even get away with using it to power water outlets in different rooms.

Size and placement

The Bosch tankless water heater is very small and lightweight, weighing in at only 5lbs so it’s easy to mount on a wall in a sink cabinet, or anywhere else for that matter. It can be placed vertically or horizontally so if you’re in a cozy little boat or RV, you can certainly fit it in somewhere not too conspicuous. It is a bit frustrating that you cannot put it in another room though, it has to go near the outlet of water or you won’t get the instant heating you want.

Lacks modulation control

This unit is not the best electric tankless water heater in terms of smart technology. Though the materials are sufficient for durability including a copper heating element, there is no automatic modulation control. It is set to raise the temperature of your water by the same amount every time. So if you’re using water that is already hot, then careful you don’t get scalded. It also doesn’t have the safety control of maxing the temperature of that water to 140°F. This could be quite unsafe in environments with vulnerable people. You can still, of course, set the thermostat lower.

The Good:

  • Can be placed in a variety of locations
  • Small and lightweight
  • Has a variety of models for your choosing

The Bad:

  • No modulating controls
  • Can only use in one room
  • Relatively low flow rates

Things to consider when looking for the best electric tankless water heater

Climate and flow rate

To guarantee you get the best electric tankless water heater for your home, you definitely will need to consider what flow rate suits the climate you live in. Generally, a higher flow rate results in more heated water that stays hot for longer in your desired location. However, if you are in a colder climate, you will need to round up the specs by at least 30%, closer to 50%. This is because a colder climate means the water needs more heating up. If you are in a warmer climate, you benefit from not having to spend as much on lower flow rate heaters. Most manufacturers should provide a guide, telling you which location of the country requires what temperature rise and subsequent flow rate.

How many outlets do you need powering?

Sinks, dishwashers, washers, showers? However many you want running at the same time will decide how much of a flow rate you need. This is also linked to the climate you live in as in a warmer climate, more outlets can run at the same time. For example, a 2.0 GPM would be alright for multiple outlet use in warmer climates but not colder ones. There should be guides and charts provided to help you work out what you need with the manufacturer’s listing.

Energy efficiency

Energy efficiency is great for the environment, but for a little more incentive, how about huge savings on your bills? All electric tankless water heaters are designed with this goal in mind but some do it better than others so it’s worth looking at the energy efficiency percentage. Every penny counts after all. 99% and above is ideal.


This one can often be overlooked but it’s also an important feature that makes the electric tankless better than conventional heaters, as it’s always much more compact. Compact doesn’t necessarily mean it’s suited to your tiny boat’s bathroom though. Make sure you look at the dimensions and see if it fits in your desired location.


The materials of the unit can contribute to a more efficient heater and/or a more durable unit. Copper is a great heat conductor so will make sure your water is heated in a flash. For durability, look for materials such as steel which are sturdy but not too heavy. Infrared builds up much less limescale and requires less maintenance but results in a lower flow rate and is more expensive.

Does it make a noise?

Noise is mostly an unnecessary flaw in a water heater. There are not many mechanics going on inside, so a little bit of design development and it should be quiet enough not to interrupt a sing-song in the shower. You might not mind whether there’s noise or not though, especially if you’re putting it in a location where it’s already noisy so the water heater will be drowned out.

Michael is our staff writer. He has a diploma in journalism and also works in an IT company. His hobbies are gadgets, devices, and new technologies, which in turn are his favorite topics for research and writing articles.

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