Bosch Tankless Water Heater Reviews [2022]

| Last Updated: September 2, 2021

Hot water can be a luxury for most people, especially in winter. Nothing can make you feel more relaxed than a nice, hot shower or bath. But for all this, you need to have hot water in the first place, which is not possible without a water heater.

There are different types, such as gas or electric, which get the job done.

In this article, we will be discussing details about the different types of water heaters manufactured by Bosch, and which one is best for you and meets your requirements.

How Does Bosch Compare to the Competition?

Bosch is a company renowned all over the world for their technology and services, which started out all the way back in 1886 and is still not just going strong, but is actually even better than ever. It is able to hold a strong list of clientele, some would say, unlike its competitors. Some things that make Bosch a better company than its competitors are:

Old and Experienced

Bosch was born back in 1886, and that makes it over a century-old company. It has been providing people with what they want and need for a long time now. Its old age makes it a sort of pioneer, a beacon for the other companies, and new younger competitors.

In addition to that, it has remained solid and standing for so long, with the wishes of the customers always being met and the people always being satisfied with their service. It is a conglomerate, which has been here for a long time and will probably be here in the many years to come as well.  

On Top of the Game

Bosch being an older, more experienced company, knows the ins and outs of the business. As part of a business in which you can be a king one moment and an outcast the other, they have set an example and stood tall through all kinds of good and bad times. The result of their steadfastness and the steady climb is that now they are fully aware of how to tackle even the most difficult of circumstances, which cannot be said for most of their competition. They have experience behind them and, as such, are on top of their game.

Know What People Want

Being an experienced company has its perks, what with knowing the ins and outs of the business, with which friends are actual friends and which are hidden enemies who want to steal your ideas. You get to know and understand all of this. And not just get to know the friendly faces, but to know your own customers and what they want too. If you want a list of prominent clientele and satisfied clients, you need to know your people and what they want from you. And Bosch so far has nailed this.

Comparison of the Best Bosch Tank-less Water Heaters

  • Highest performing and fully condensing
  • Uses heat from the exhaust gas to preheat cold water
  • Has electronic ignition and direct vent
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  • A range of power outputs, from 3.4Kw to 12kW lets you have hot water without any amount of wait
  • Comes with thermostatic control
  • Activation flow rate ranges from 0.5 to 0.75 gallons (GPM)
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  • Has maximum input of 175,000 (BTU)
  • Intelligent cascade of up to 24 units
  • Best for the money
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  • Activation flow rates of 0.6 and 0.8 gallons (GPM).
  • Has thermal efficiency of 95% and a built-in inlet water filter
  • Best Bosch Electric Tankless Water Heater
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  • Has maximum input of 199,000 (BTU)
  • Intelligent cascade of 24 units
  • Best Bosch Gas Tankless Water Heater
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To be certain of your choice, it’s better to compare the different options available and see which one is the most suited for you. Thus, here’s a comparison of Bosch’s top models. 

Model Name


Unit Size (L”xW”xH”)


Energy Efficiency (SEER)


Condenser Fan Motor


Cost of Unit Only


Installation Cost


Bosch 830 ES LP Therm


 0. 82


$1,050 – $1,175

$600 – $1,500

Bosch 940 ES NG 


 0. 82 


$1,250 – $1,575

$600 – $1,500

Bosch Therm C 1210 ESC 

17.87×30.x 4.25



$1,875 – $2,200

$600 – $1,500

Bosch Tronic 3000 Point-of-Use 

6.5×12.25x 3



$160 – $225


Bosch Tronic 6000 




$600 – $715

$600 – $1,500

Review of the Best Bosch Tank-less Water Heaters

As you might have already gathered, there are several different kinds of tank-less heaters put out by Bosch. We’ve categorized them according to their kinds to make it easier for you to pick one.

Gas Water Heaters

The gas water heaters from BOSCH are discussed below:

Best Overall

Bosch Therm C 1210 ESC Condensing

Why it Stands Out to Us

It stands out to us because it is a highly efficient and fully condensing tank-less water heater. It is great that a product like this has been manufactured by BOSCH because it is like nothing else. It has some amazing features, such as built-in freeze protection to keep it from the cold environment in case of snowfall.

Plus, the design of the device itself is space-saving. It takes up only a small amount of space in your home and doesn’t get in the way. It also consists of serviceable parts so that the device can be used for years to come, etc.

Bottom Line

It is a really great product that should definitely be given a try. It is time-saving, and a great help to you as you won’t have to wait for hot water and will get it instantly. It saves energy as well, being near 98% efficient when it comes to saving gas and electricity.

It is also their highest performing condensation device, which takes and recycles the emitted gas so that the least amount of NOX is released into the environment. And all of these are just the tip of the iceberg.


Has up to 98% thermal efficiency

Two pipe venting options, concentric and twin

The minimum activation flow is 0.5 gallons per minute

Comes with built-in freeze protection and precise controls

Design is space-saving, and the parts are 100% serviceable


Does not work on a low gas supply

Difficult to reset after error code display

Only works well when there is a high supply of gas


Bosch Tronic 3000 Point-of-Use Electric Tank-less Water Heater

Bosch Electric Tankless Water Heater - Eliminate Time for Hot Water - Easy Installation, 17.3 kW

Why it Stands Out to Us

It stands out to us because of its great performance and amazing features. First of all, it is completely different from the gas tank-less water heaters and functions differently as well. It can be installed anywhere inside the house and does not hold water in a storage tank, making it easy to handle.

It works at 97% thermal capacity, which eliminates any chances of standby hot water loss, thus being efficient and saving you money and energy. It is space-conserving since it is compact and lightweight and doesn’t even need a specific area to function. It can be mounted on a wall or even outside.

Bottom Line

It is a great product that can benefit you in many ways. It can conserve energy and money as it works at 97% thermal capacity and doesn’t hold water in a storage tank. It takes up little to no floor space as it can be mounted on walls or outside of the house.

Moreover, it gives you hot water on demand, meaning you don’t have to wait around for a shower or a bath, especially if you are in a hurry. It has a long life, as unlike other heaters, it can work for up to 20+ years. It needs to be connected to copper or stainless steel plumbing, rather than plastic or PVC, as the hot water exposure may damage them. Overall, it’s a great product that needs to be commonly used by the people.


Can be used in RVs and boats as well

98% efficient with minimal to no stand-by loss

Voltage requirements of 120V, 240V, and 277V

Very low maintenance with no venting required

Takes up far less space than regular water heaters


No temperature adjustment

Needs constant flow sensor resetting

No temperature change no matter how much the flow rate is increased

Best for the Money

Bosch 830 ES LP Therm Tank-less Water Heater

Bosch ProTL 175L (Therm 830ES-LP) Tankless Water Heater, Liquid Propane

Why it Stands Out to Us

It stands out to us because it is a reliable product with great features. It is capable of giving so many benefits like low NOx emissions that can lead to cleaner air in our environment. What we love is that it is a burner that is specifically designed to keep on giving out hot water.

Endless hot water supply would make anyone fall in love with this product! Plus, the unit comes with easy maintenance because the inlet water system has external excess, so it will be super easy to clean.

Bottom Line

It is a really good product that deserves to be at least given a try. It gives you the luxury of instant hot water when you do not want to or have the time to wait for it to heat up. Plus, it is again very easy to handle, compact and lightweight, with the added ease of installation.

It is an advanced product with better software and safety controls, which only requires an input of 175,000 per hour. It is the ideal product for a busy household, and with the intelligent cascading of 24 units, it can even become a part of larger homes.


Has ultra-low NOx emission certification

Durable heat exchanger with copper pipes

Digital display for precise temperature setting

Patented burner design generates endless hot water

Has external access to the inlet water system for maintenance purposes


False error code display in some cases

Complaints of water temperature fluctuations

Water heaters found with leaks that ruined the entire machine

Best Bosch Electric Tankless Water Heater

Bosch Electric Tankless Water Heater

Bosch 940 ES NG Tankless Water Heater, Natural Gas

Why it Stands Out to Us

It stands out to us because it is a very good product with a lot of great features that make it that way. It has an activation flow of up to 0.8 gallons with a thermal efficiency of 95%, which saves you both money and energy. It also has a knob for the adjustment of temperature, which is a big improvement from the previous model.

It is compact and easy to handle and can be mounted on walls or outdoors, as per your preference. An LED display is also present to make sure you know exactly what the temperature is set at. Overall, it’s a simple and effective product that should definitely be given a chance.

Bottom Line

It is a great product and deserves to be recognized as such. It has a number of great features that make it top of the line and easy to handle for the people who buy it. It gives you immediate access to hot water, and it doesn’t take running water to get the hot water to come out.

It has an LED display to show the temperature and a knob to adjust it to your liking. It also saves you money and energy, being 95% thermally efficient, and a whole lot of other features that you will discover when you give this a try yourself.


It is compact, easy to handle and lightweight

A knob is present for the adjustment of temperature

Thermostatic modulation provides a constant output temperature

Great for small dwellings where normal heaters just take too long to function

An LED display is there to make sure the precise temperature is set every time


Product quality has dropped

Will not give hot water even though the light is on

After resetting the product a few times, it completely stopped working

Best Bosch Gas Tankless Water Heater

Bosch 940 ES NG Tankless Water Heater

Why it Stands Out to Us

It stands out to us because it can be used as an indoor heater and can be fitted outdoors as well. It hardly takes up any space, so it is good for either of them. It also has other features such as 3 to 4-inch vents that can be arranged horizontally or vertically to get rid of excess gases.

There’s also a durable heat exchanger design in which all the pipes are made of copper. The unit also features a fully modulating burner, which generates a lot of hot water. Other features include a digital control panel that helps you control the temperature settings and maintain stability, etc. All this and many more make this product really stand out from its competition.

Bottom Line

This is a good product that is highly recommended for use. It gives you the benefit of not having to wait for hot water to take a shower or a bath because it instantly warms up the water. Also, it takes up little to no space in your home or outside, so you can have it mounted on a wall even, and it will still function just fine.

Apart from the dual placement of indoor or outdoor installation, you have both options open for you so you can just get it done to your liking. Bosch tries to satisfy its customers in every way, and with the use of this product, they can surely count you as one of their regulars.


Can be installed outdoors or indoors

It is the highest capacity non-condensing model

Has sealed combustion and dual-fan technology

Has electronic ignition and a patented burner design

Vents both vertically and horizontally with 3-inch or 4-inch stainless steel


Constant error codes being given in some cases

Incorrectly wired control panel has been reported

Flow rate needed to be higher for water heating in some cases

What Kind of Warranty Does Bosch Offer?

The warranty that Bosch offers can be divided into two parts:

Manufacturer’s and Extended Warranty

Bosch offers manufacturer’s as well as extended warranty after the payment of an additional fee. It is very helpful in long term cases because you never know what may happen down the road. Its customer service is also very accommodating and will change your damaged product or device, within the limits of the warranty, for a new one. Generally, a manufacturer’s warranty lasts only 2 to 3 years, so it is good to get an extended warranty so that the company may be able to recompense you for damages that may come under the warranty limits.

Warranty for BOSCH Tankless Water Heaters

Now, generally, tankless water heaters have a lifetime of 20+ years. This is because unlike normal water heaters with storage tanks, they do not corrode or rust because of water damage over the years. It makes them last for up to or more than 20 years, whereas normal water heaters only last for 6 to 12 years.

Bosch gives warranties based on different aspects and is divided into a heat exchanger, all other parts, and labor. Usually, the heat exchanger warranty is from 5 to 15 years based on the model. The warranty for all other parts is from 2 to 5 years, but the model and the labor warranty is for one year. 

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Who is Bosch?

Bosch is a globally known multinational German company famous for its technology and services. It has been leading in operations of the automotive, industrial, and building technology, as well as consumer goods, for a long time.

The company was founded in Stuttgart, Germany, all the way back in 1886, by Robert Bosch. Nowadays, it is owned 92% by Robert Bosch Stiftung, a charity named after him. It also has a few subsidiaries such as the BSH Hausgeräte, which is the largest manufacturer of home appliances in all of Europe and was started in 1967 as a joint merger between Bosch and Siemens. 


Bosch is a world-renowned company that has dabbled in everything from automotive to home appliances and is still a leading company in all these things. Its tankless water heaters are a great home appliance that meets the requirements of the customers and make sure that they are satisfied with the product provided. 

People Also Ask

Now, some people may still not understand a few things and may become confused. For such people, we have compiled a list of commonly asked questions, which we hope will be helpful for them in finding out their required answers.

How Do You Flush a Bosch Tankless Water Heater?

The steps to flush a Bosch tankless water heater are as follows:

1. Shut the unit and the water supply OFF.

2. Release the water pressure by opening hot water taps.

3. Disconnect the water inlet and outlet and drain the water.

4. Take one of the three hoses, connecting it with the inlet of the water heater and outlet of the pump.

5. Take the second hose, connecting one end to the water heater outlet and submersing the other end in the bucket with the descaling solution.

6. Take the third hose, connecting one end to the inlet of the pump, and putting the other in the bucket. This will act as a filter to keep the larger particles from entering the system again.

7. Check to make sure all the connections are tight and that there is no leakage.

8. Run the pump through the tankless unit and its heat exchanger. Depending on the lime build-up, the returning solution might be quite dirty. It will take a while for it to come out fully clear.

9. After you are done with flushing out the heat exchanger, it is time to connect with the cold water line and flush the unit with clean water.

10. Connect the hot water line and open all the valves. Turn the power back on and run the unit like normal.

How Long Do Tankless Water Heaters Last?

Unlike other water heaters that store water in a tank and corrode and rust over time, tankless water heaters are able to last nearly 20 or more years, depending on the make of the product.

Do Tankless Water Heaters Run Out of Hot Water?

In a tankless water heater, the water is heated up as it is used. There is no place to store the water, like a storage tank in some water heaters. For example, if you turn on the shower for hot water, the heater system will detect the movement of water in the pipelines and begin heating it through a heat exchanger. It will keep doing this for as long as the water is needed, so in this sense, no, tankless water heaters do not run out of hot water.

How Do I Choose the Right Size of a Tankless Water Heater?

The following steps will be helpful in choosing the right size of a tankless water heater:

1. Calculate the maximum number of taps you want to run and their total flow rate. Then, add them up (gallons per minute). This is the flow rate you will want for the water heater.

2. Calculate your required temperature rise. To do this, subtract the incoming water temperature from the desired output temperature. You will get your temperature rise value.

3. How much hot water is needed at a time? Do you need to run 2 showers at the same time? Or a shower and a sink? Flow rates will determine this point.

4. Remember, gas tankless water heaters are able to have a larger temperature rise than electric ones, according to the flow rate.

These are just a few pointers to make sure you buy the perfect product for you and your family. You may use the calculator below to check your flow rate.

My name is Bob Wells and I am a retired HVAC tech from Washington state. I am currently retired and no longer do much with HVAC, however, I feel like I have a lot of knowledge in the subject and I wanted to create a website where I could talk about what I've learned and help upcoming HVAC techs. Find more info about me and HVAC Training 101.