Best Shower Tankless Water Heater

Buying the best shower water heater is not a simple thing. You need to consider many elements before making a final decision. You can be tempted and search for an affordable solution by buying a point of use water heater that is easy to install. Before you do that, you should know that the point of use water heaters are usually not powerful and they don’t work well in some situations. 

Best Shower Tankless Water Heater

To avoid unpleasant scenarios, you should carefully go through this review and carefully read and weight everything that is said. Only that way you can avoid making a mistake and actually buy a water heater that you need. 

For a start, you should know that showering uses more hot water per minute than a simple sink. Because of that, from the beginning, you should look at more powerful water heaters. Although if you are living alone, maybe you can get away with a simple and affordable solution but to know that you need to go through this water heater buying guide and decide on your own.

What Is A Shower Water Heater?

Before anything else, we need to say a few words about what exactly is a shower water heater. Any water heater can be used in a bathroom for showering. But you need to know that a simple water sink uses 3GPM while showering uses around 8GPM. As you can see, you will need a water heater that can provide as almost as a double amount of hot water that the usual under sink water heater can do.

That is the primary and most crucial difference between the sink water heater and the showering water heater. However, in a hot climate where winter temperature rarely drops below 20°C, a less powerful tankless water heater can be used. 

TOP 9 Best Shower Water Heaters

Now that we know that for a decent shower water heater, we need to look at a more powerful device, let’s see which are the best tankless water heaters that can be an ideal solution for heating showering water.

EcoSmart ECO 27

EcoSmart ECO 27 is a powerful water heater with a maximum capacity of 27Kw. That is a serious power, and without a doubt, this water heater can provide a whole house with hot water. However, many homes that do require such power usually use a more affordable gas-fueled water heater. But in a bathroom, it is not wise to install a gas-fueled water heater for many reasons. The main reason is the danger of leaked gas and CO2 accumulation. 

Because of that, electric powered water heaters are the number one choice for a bathroom installation. ECO 27 is simple to install a water heater, but still, you will need to have a decent electrical infrastructure to run this monster. You will need 3x 40AMP breakers and 3x 8 AWG cable. In total, ECO 27 needs up to 113 AMPs. This is a lot and many homeowners that didn’t think about that kind of power needs at the time they were building houses simply did not place such demanding power infrastructure.

Save SpaceTraditional tank heaters take up a lot of space. But EcoSmart’s sleek, wall-mounted design frees up floor space for more storage.
Save EnergyEcoSmart features the most advanced self-modulating technology, only using the amount of energy needed.


  • Powerful
  • Cool Design
  • LCD Display
  • Simple Temperature Control
  • Saves Money on Water Heating Costs
  • Robust Design
  • Durable
  • Replaceable Parts


  • Needs Electric Infrastructure That Can Provide 113 AMPs

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Stiebel Eltron Tempra 24 Plus

For many bathrooms, a 27Kw is overkill, and you may be looking for a weaker water heater. Stiebel Eltron Tempra 24 Plus can provide 24Kw, which is not much less than 27Kw, but it is less. It means that less electricity will be used and you can get away with much weaker electric infrastructure. 

Just like with all other tankless water heaters, you are saving money because there is no standby loss. However, with an advanced flow feature, this water heater is capable of reducing a flow if the demand for hot water is great. This is very useful in wintertime when tap water temperature drastically drops. However, in a hot climate, this water heater is capable of supplying several sinks and showers simultaneously. Because of that power, it can be used as a water heating solution for a whole house. 

If you decide to place it in the bathroom, you will not make a mistake because the installation is simple, and by design, this water heater is not large, and it has beautiful decor. No need for ventilation just makes it perfect as a bathroom water heater solution.

Constant Energy Savings99% Energy Efficiency plus intelligent self-modulating technology continually ensures the least amount of energy used.
Smaller Electric BillsSave at least 15-20% on the hot water portion of your electric bill.


  • Cool Design
  • Simple to Use
  • Simple to Install
  • Lots of Power
  • Advanced Water Flow
  • German Quality


  • 24Kw of Power Still Requires a Decent Electric Infrastructure

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Rheem RTEX-13

Rheem is, without a doubt, a leader in home appliances. Rheem provides many tools and devices. Rheem stands for a high-quality brand. Almost 100 years old company is the leader in providing home appliances to customers in North America.

RTEX-13 is a unique model that can be used as a point of use water heater. It is a very small water heater that has the power of 13Kw. 13Kw is more than enough power for showering. You will only need one 60 AMP breaker and 6 AWG wire to power this little monster. 

By design, this water heater is at the top. It has an LCD display for temperature and a knob that you can use to turn the temperature up or down. On hot days you really don’t need near-boiling water to take a shower. In fact, warm water is more than enough. While in the wintertime, even if you put the knob to the maximum, you will get pleasant water for showering.

Easy InstallationThreaded for easy replacement, simple installation, digital temperature display 54 A. 13kW Model Flow Rate: up to 3.17 GPM.
Energy Efficient99.8% energy efficient. External controls to adjust temperature in increments of 1°f. Water-Saver Shower Head – 1.5 GPM


  • Well Done Design
  • LCD Temperature Display
  • Simple To Use
  • Only 13Kw
  • Energy Efficient
  • Popular Brand


  • In some big homes in a cold climate, this water heater is simply not an option.

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Instant Electric Hot Tankless Water Heater by Dltsli

Dltsi builds a decent point of use water heater, which can provide instant hot water for showering. Dltsi has only 5.5Kw power. That power is more than enough for one showering. Usually, this device is used in a kitchen, bathroom, or hair salon. In a hair salon, it is a perfect solution if you need cheap hot water. One of the most significant advantages that this model offers is a digital temperature display. You can choose the maximum temperature for hot water, and by that, you can be sure that the water in pipes will never get too hot. For hair salon, that is a fantastic feature.

Dltsi temperature is adjustable between 25°C and 55°C. Small temperature range and inability to go near-boiling temperatures is one problem which in hot climates should not be big. However, in cold climates with snow and temperatures below zero, lack of power may be a significant problem. If you live in such a cold environment, then I highly suggest to get a more powerful water heater or else you will be showering with cold water.

Multiple security protection for your familyThe water heater is equipped with electricity leakage protector, safety thermal cut-off, and dry heating protector. Which make it works safely for your family.
Mini sized and compact design of water heaterSuper compact and lightweight designed to save space for your bathroom or kitchen.


  • Small
  • Cool Design
  • Digital Temperature Display
  • Low Energy Consumption
  • Ideal For Showering in Hot Climate


  • Weak for Cold Climate

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Marey ECO110

Marey ECO110 is a german product that uses patented technology, which prevents hard water build-up from chlorine and calcium. It has 11Kw power, which is enough to provide hot water for a shower even if the outdoor temperature is low. But at the same time, this product is easily installed even in low space compartments. It can easily go undetectable under the sink. 6 AWG wire is required as well as 60 AMP breaker. 

Marey is a company that is in business for over 60 years, and they are a well-known manufacturer of tankless water heaters. It is no surprise at all that they give a five-year warranty on this product. Customer support is also on a high level, and you won’t have any trouble connecting it top the pipes in your home. The only concern can be electric installations, which you need to check with your electrician.

SMART TechnologyEasy management and simple adjustments on a LCD Panel allows you to program the exact desired water temperature thereby optimizing electricity consumption.
Endless hot water on demandActivated by water pressure (5 to 85 PSI) from the moment the faucet is opened.


  • Small and Compact
  • Good Design
  • Powerful
  • Point of Use Solution for Showering
  • German Quality
  • 5 Year Warranty


  • You Can be Tempted to use it as a whole house water heater, but for that purpose, it may be too weak, especially if you live in a cold climate area.

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Sio Green SIO18 v2

Sio Green SIO18 v2 won’t be declared as a best-looking water heater. However, 18Kw power and anti-corrosion features put this water heater on a most-wanted list of water heaters for showering. It is a compact water heater which can be placed in the bathroom or kitchen without a problem. Since this device doesn’t have a tank, you can easily install it in a small place like a cabinet. Putting it inside the cabinet is a good strategy since I already said that the looks of the Sio Green SIO18 v2 are not the best.

Still, with a not so attractive design, this water heater has a digital temperature display, which will tell you the exact water temperature. You can easily adjust the water temperature with buttons on display. This water heater uses quartz elements and infrared rays, which prevent corrosion and calcium deposit. In other words, no maintenance is needed. This water heater can further save you money by saving on maintenance costs.

Automatic Modulating TechnologyIn Automatic mode, the software is using smart modulating technology and formula to calculate the difference between the desired temperature and current temperature, then predicts how much power it requires to ensure the process temperature remains as close to the set point as possible.
Temperature AdjustmentOur premium Sio18 designed for high performance usage in Residential operating 24h/a day for 365 days a year.


  • Advanced Technology
  • No Corrosion
  • No Calcium Deposits
  • No Maintenance
  • Compact
  • Affordable
  • Superior Heating


  • Design

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Mini Instant Tankless Water Heater by Lyty

Just like Dltsi, this water heater is also in its own category. We can agree that these low power water heaters are only good for point of use. You can place it under a sink or near a shower and have hot water on demand. If your needs are high, it is highly possible that this low powered water heater won’t be able to supply. It can also have some troubles during the winter when the outside temperature drops. 

It can provide hot water up to 55°C without a problem, that is the maximum temperature setting. For a pleasant shower, that temperature is more than enough. You can install this water heater on your own since it can probably use the current electric infrastructure. It only needs a 25AMP breaker, which a decent house should have by default.

Without a doubt, this is one of the most energy-efficient water heaters on the market. It can be installed close to the shower, which means that the hot water will flow in a matter of seconds.

Request Breaker30A and Standard Pipe Section G1/2″ water connection (Very important: You must run this heater on 220 or 240 Voltage).
Constant TemperatureConstant temperature function with touch control digital LCD temperature dispaly in 1-degree increments allows control of hot water.


  • Compact
  • Easy to Install
  • Easy to Use
  • Digital Temperature Display
  • Low Power Consumption
  • Safety Protocols


  • Weak for Heavy Hot Water Demands

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Eemax EEM24018

Eemax EEM24018 is at the top if we rate only design. Blue front panel fits almost any bathroom. By the looks, this tankless water heater is the number one choice for a bathroom. It can easily be placed near the shower because of its compact size. LED display will tell you in real-time exact water temperature. 

Adjusting the temperature is very easy, you use knob which you turn left or right depending on if you want higher or lower water temperature. This tankless water heater can be used as a point of use system in any place in your home as well as a tank booster to help existing water heater or stand-alone whole house system. For a whole-house system, you need to check it in detail because if you have high demands for hot water, it is possible this water heater will not be powerful enough.

Your house needs to have two 40AMP breakers and 8AWG wire to supply this water heater with electric power. Some people got away with 6 AWG wire, but I am recommending 8 AWG, better to be safe than sorry.

Continuous Water SupplyTankless water heaters provide a continuous Supply of hot water and only heats the water you need, when you need it.
Self-modulating TechnologyThe most advanced, self-modulating technology available, meaning the unit will adjust how much energy needs to be input based on how much hot water is needed.


  • Cool Design
  • Powerful Enough
  • Digital Temperature Display
  • Low Energy Consumption
  • Durable
  • Robust
  • Affordable


  • Not For Cold Climate

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iHeat Tankless S-12

iHeat Tankless S-12 is one of the most affordable tankless water heaters on the list. It is the small but mighty water heater that can be installed under a sink, near the shower, or even in a cabinet. 12Kw power is good enough for a whole house system if your demands for hot water are not significant. However, it is best used as a point of use device which works very good at supplying a shower with hot water. In a hot climate can serve as a whole house system while in a cold environment, it is best to be used as a point of use system.

Design is not a revolutionary, standard box with buttons to control temperature and display, which provides real-time water temperature. Only 7.5lb allows this water heater to be used on boats, yachts, cottages, and other properties that don’t require a more powerful water heater.

Use It In Highly Sterile ApplicationsHeat tank less s series can also be used in highly sterile applications like commercial kitchens, hospitals, clinics, and even schools where cleanliness is of the highest importance.
Water Proof ConstructionWater proof construction allows you to easily and safely control the temperature by using our water proof interactive touch pad.


  • Affordable
  • Compact
  • Lightweight
  • Saves Energy
  • Stainless Steel


  • Design

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How Shower Water Heater Works?

The shower water heater needs to be placed near the shower. It needs to be small because many bathrooms have very little space. In other words, it needs to be a tankless water heater because they are much smaller than the ordinary tank-based water heaters.

Placing the shower water heater as close to the showering cabin as possible will make sure that there is not wait for hot water. Water is not preheated and is heated only on demand. This way, you save money.

The heating process is simple; cold water goes through a water heater, which then uses electric power or gas to heat it.

Choose The Right Size of Shower Water Heater For Your Bathroom

Some bathrooms are small, and only little devices like Lyty or Dlsti may fit in. Other homes have a large bathroom where you can place a whole house water heating system. You need to do the measurement on your own and choose the one that fits inside your bathroom but also supplies all the hot water demands.

What Type of Water Heater is Best For Your Shower

If you don’t have a whole house water heating system, then without any doubt, the best water heater for the shower is a point of use. On the list above, you can find nine shower water heaters powered by electricity and one powered with propane

Tankless water heaters have a clear advantage over tank water heaters. It is highly recommended that you get a tankless water heater.

How Long It Takes To Heat Water?

Water is heated instantly as soon as there is a demand for hot water, the water heater will start heating it. However, there can be a wait time for hot water, which depends on how far is the water heater from the sink. Usually, people place the point of demand water heaters close to the shower, which means that hot water will be available in a second.

What Are The Benefits of Using Shower Water Heater

Shower water heaters have many advantages that every homeowner appreciates.

Low Initial Investment

The initial price you pay for a decent shower water heater is way smaller than you would pay for a whole house system. Why spend more if you only need hot water while showering.


The majority of water heaters in the bathroom are powered by electricity. There are no gases, no carbon dioxide releases. The heating process is safe for you as well as for nature.

Easy to Install

If you are somehow decent with tools, you can probably install it on your own. Even if you hire someone to install a shower water heater, I am sure you won’t spend a lot of money on that.

Saves Energy

Tankless water heaters use energy only when there is a demand for hot water. In that way, you are saving money and power. If nobody showers for a long time, your bills will be zero.

No Need For Ventilation

There is no carbon dioxide leak, no gas leak, no other dangerous fumes in the system that may harm you. Because of that, there is no need for ventilation. In the end, that is the main reason why people choose electric tankless water heater for showering.


Some water heaters are easily installed, while others will require lots of work. Some small, low power water heaters can be installed on your own. On the other hand, a powerful water heater will need a new electric infrastructure, which means lots of work not only by plumber but also by an electrician.

DIY – Install Shower Water Heater – Step By Step

For the brave ones, here is a step-by-step guide on how to install a shower water heater on your own.

Pick Up The Location

First, you need to find the right spot that is near the shower. Make sure there is enough room so all pipes and water heater can fit.

Choose The Right Size

You must be careful and make sure you don’t buy a too large water heater. Make sure the water heater is the right size, and that there is enough room for pipes and all the connections that need to be done.

Test Electric Installation and Proper Wiring

Now, this part is hard to do on your own if you are not an electrician. You need to make sure that your house has proper breakers and proper wire for the wanted electric water heater. 

If you have all that is required already installed, then you can probably connect the water heater to the power supply. Some water heaters are so simple that all you need to do is plug them in. On the other hand, some of them will require a real electrician work which I don’t recommend to do it on your own if you are not an electrician.

Fitting The Pipes

The next step is simple on paper but hard in practice. Connect the pipes. Sounds easy, but you need to make sure that there is no leakage. You will probably need to use particular tools like heat guns and soldering wire to make sure joints don’t leak water.

Check Everything

Before you let it run, make sure everything is connected and ready for a test run. For few minutes, watch if there is water leakage; if everything is working as it should, you can relax and forget about it because many of the advanced tankless water heaters are set and forget machines that require very little to no maintenance.

Installation Cost

It is hard to say how much will installation costs you. If you pick a simple water heater which you can install on your own, then there are no costs. While some big water heaters that require lots of electric power will need a huge investment since you will need to install new, more powerful breakers and drag new robust wires.

Exact installation costs can be measured only by the professional who will visit your home and put everything down on paper.

Choose The Right Water Heater For Your Shower

By going through this buying guide for the best shower water heater, I am sure you will pick the right water heater for your needs. Remember, size matters as well as power and climate. If you calculate these three factors together, you are on the right path to make the right decision.


I hope this buying guide will help you in spending the money in the right way. If you bought any of the mentioned water heaters on this best shower water heater list, let me know what you think about it in the comment box below.

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