Bosch Tankless Water Heater (2020 Review)

Bosch Tankless Water Heater (2020 Review)

Sometimes, renovating or moving means buying new appliances that bring comfort and convenience and, even hot water, into the home. A Bosch tankless water heater usually falls on the list of what people replace once they move. Considering that there are a myriad of Bosch tankless water heaters are out there today which one should you choose?

With this question in mind, we will show you why you may opt for a tankless water heater instead of the traditional heater, and introduce you to Bosch’s tankless water heater line. While there are many good brands in the home appliance industry, Bosch appliances have continued to maintain a high standard of quality that distinguishes them as one of the best brands out there. There are certain essential factors you need to consider before making this purchase, and we’ll discuss how Bosch has incorporated this in their line of tankless water heaters.

What is a Tankless Water Heater?

Do you know that water heaters consume about 20% of your entire energy use at home? Traditional water heaters are built to heat and store water for later use, which accounts for the enormous energy consumption. That’s one of the advantages tankless water heaters have over the traditional ones. In essence, they save you a lot of money in energy bills.

But that’s just one of the advantages of tankless water heaters. Good water heaters are also compact to fit into small spaces while offering a decent water flow rate. Bosch tankless water heaters are equipped with high-quality heat exchangers to reduce the wait time, and their performance has been very reliable.

What are the Benefits of Bosch Tankless Water Heaters?

Here are some reasons why you should consider a tankless water heater instead of the traditional water heaters:

  • Reduction in overall energy costs. Tankless water heaters provide hot water “on-demand” and only work when needed. This can potentially reduce your total energy spending by 15% in a year.
  • They are installed at the point of use. Traditional water heaters are typically placed in strategic locations, which may be far from your point of use. Tankless water heaters are small and built to be installed where you need them.
  • They provide cleaner water even with prolonged use. Traditional water heaters eventually build up rust and scale as a result of storing water. Tankless heaters do not store water and therefore provide cleaner water.
  • They last twice as long as traditional water heaters. While the lifespan of a traditional water heater is between 6 -12 years, tankless water heaters can last up to 20 years.

Bosch Tankless Water Heater (2020 Review)

What to Consider Before Buying a Tankless Water Heater

Before you purchase your tankless water heater, there are some crucial factors you should consider.

Heating Performance

Tankless or instantaneous water heaters do not store water, but instead, heat water that is flowing through it when the tap is turned on. The water either passes through a gas-fired burner or an electric heating element that heats it and sends it through to the tap.

Inferior water heaters may have faulty heating elements that develop hot spots at some point in their lifespan. This will lead to an increase in wait time or the water produced not being hot enough. Premium water heating brands utilize quality heating elements or heat exchangers to ensure a continuous supply of hot water.

Energy Efficiency

One of the highlights of tankless water heaters is the low energy use compared to the traditional water heaters. But this advantage is lost if your tankless water heater still consumes as much energy as the typical storage water heater.

The energy efficiency of a water heater is indicated by its energy factor (EF) rating. Water heaters with higher EF ratings have better thermal efficiency. Bosch tankless water heaters typically have a 95 – 98% thermal efficiency. It’s best to choose water heaters with an EF that is above 90%.


Tankless water heaters do not store water and are meant to provide hot water at the point of use. With this in mind, they have to be small enough to fit into small places where they won’t stand out. Bigger tankless water heaters (without a higher GPM rate) may be hard to fit into small spaces. Opt for compact tankless water heaters that can fit into the available spaces.

Bosch Tankless Water Heater (2020 Review)

Flow Rate

The flow rate or the gallons-per-minute (GPM) measures the rate at which a tankless water heater sends hot water to the tap. A 1 GPM heater is suitable for handwashing, but will not be so great for bathing (which typically requires about 2.5 GPM).

Typically, the average water heater has a flow rate of 2.5 GPM. But this may not be enough, especially if more than one person is bathing at the same time. In this case, you may need a central tankless water heater with a flow rate of 4 GPM or two tankless 2.5 GPM water heaters.

Fuel Source (Electric vs. Gas)

There are two types of tankless water heaters (according to fuel source) – gas tankless water heaters and electric water heaters. Gas water heaters make use of burners to heat the water while electric water heaters make use of heating elements.

Gas tankless water heaters generally require additional special measures for health safety, and they may lead to additional up-front costs. Electric water heaters have lower up-front costs but may accrue higher operating costs (for maintenance) with time.

Bosch Tankless Water Heater (2020 Review)


One of the advantages of tankless water heaters is their versatility; they have a more extensive range of applications. An excellent tankless water heater should be easy to install and can be plugged into a standard electric outlet. That means it can serve not just the kitchen, but also the patio, pool house, garage, attic, and even boats.


Traditional water heaters have a 6 to 12 years lifespan, thanks to rust, scale, and other maintenance issues that wear down the units over time. Tankless water heaters are designed to be free from rust and scale, which means they are meant to have a higher lifespan than the storage ones. Bosch tankless water heaters have a 20 years lifespan.

Bosch Tankless Water Heater (2020 Review)

Best Bosch Tankless Water Heaters

Bosch is a premium home appliance brand with high-quality products. There are two types of Bosch tankless water heaters (by design) – on-demand water heaters that are placed at the point of use and whole house units that are placed at a central location for hot water to be distributed to other parts of the house.

Bosch has both gas tankless water heaters and electric tankless water heaters, which are grouped in series. The 3000T series and the 6000C series are for the electric tankless water heater series, while the gas models fall into the Greentherm, Therm, and the ProTL series. Bosch gas tankless water heaters make use of the robust gas condensing technology for ultra-efficiency.

1) Bosch Tronic 3000T Series

Bosch Tronic 3000T series has three point-of-use compact-size tankless water heater models – the Tronic 3000T ES2.5 (2.5 gallons), the Tronic 3000T ES4 (4 gallons), and the Tronic 3000T ES8 (7 gallons).

Thanks to their compact size, they are designed to fit under the sink, in a cabinet, floor-mounted, or hung on the wall. When installed in noticeable locations, the 3000T series models have attractive designs that easily blend into any décor.

In terms of performance, the 3000T series units have a temperature range of 65 – 145⁰F and are very reliable. For maximum energy efficiency, the units have CFC-free thick foam insulation to keep heat in. The energy efficiency (98%) and heating performance make them perfect for cold water sandwiching – acting as a buffer for other tankless water heaters. The tanks are also glass-lined for durability.

2) Bosch Tronic 6000C Series

The Tronic 6000C series (e.g., the Tronic 6000C WH17) are compact whole house tankless water heater units designed to provide on-demand water circulation for your home. A Tronic 6000C unit has a 95% thermal efficiency, optimally eliminating possible energy losses stemming from its systems.

The Tronic 6000C series are equipped with modulating elements that ensure a constant temperature output to needed locations around the home. The unit itself has a knob for temperature adjustment and a LED display for monitoring and control.

The Tronic 6000C WH17 requires about 9 sq ft of space and professional installation. The unit is designed to supply water to about 3 or 4 different locations in the house at the same time. The whole house unit is perfect for a large household that may require multiple and simultaneous hot water needs.

3) Bosch Greentherm 9000 Series

The Greentherm 9000 gas-powered tankless water heater series has some of the best and sophisticated tankless water heaters (like the T99001 SE199) in the industry. Besides utilizing the unique Bosch condensing gas technology, the Greentherm 9000 series units have other exciting features.

The units collectively have a temperature range of 100 - 140⁰F and an average uniform energy factor (UEF) of 0.96. This means the units are designed to churn out hot water at 96% thermal efficiency. The units are equipped with combustion management sensors to ensure optimum performance and recirculation pumps that make gas recirculation easy.

Unlike other tankless water heaters, the Greentherm 9000 series units are equipped with Wi-Fi connectivity feature. You can remotely control the water heater, and also receive real-time notifications with the Greentherm 9000 app.

Other features of the Greentherm 9000 series include the stainless-steel heat exchanger, shatterproof glass cover, bottom drain ports, and user-friendly controls with LCD.

4) Bosch Therm Series

The Therm Series (Therm 830, 940, 950, 1050) are wall-mounted tankless water heaters with a UEF of 0.92. They also utilize the condensing gas technology, capturing the latent heat from the circulating gas and using the heat to preheat the water. This gives the condensing units a thermal efficiency of 98%.

The Therm series units run on versatile fuel sources (liquid propane or natural gas), have durable heat exchanger with copper pipes, and built-in digital control panel for better temperature stability. The units have a 180⁰F hot water output and support intelligent cascading for large homes (up to 24 units).

5) Bosch ProTL Series

The ProTL series models (ProTL 175, 175C, 199, 199C) are special editions of the Therm 830, 940, 950, and 1050 tankless water heater series. The models have a UEF of 0.95 and the ENERGY STAR rating. The different models have unique qualities and premium features.

The ProTL 175C is designed to offer maximum efficiency, the ProTL 199 offers the highest tankless water heater capacity, and the ProTL 175 has advanced software, supporting intelligent cascading for larger homes (up to 24 units).

Why Choose Bosch Tankless Water Heaters

Here are some reasons why you should choose a Bosch tankless water heater.

High-Quality Heat Exchangers

Bosch tankless gas water heaters are equipped with high-quality heat exchanging systems. The entire water path is made of corrosion-resistant copper and adds to the overall improved efficiency of the system.

Advanced Electronics and Diagnostic System

Bosch tankless water heaters come with advanced electronic controls and excellent diagnostic systems. The electric water heater models have a knob for adjusting the temperature and an LCD electronic display for temperature monitoring and control. The Greentherm models can be controlled remotely using the app for even more convenience.

Bosch Tankless Water Heater (2020 Review)

50% Energy Savings

Thanks to the condensing gas technology of the gas models and the foam insulation in the electric models, Bosch tankless water heaters offer ultra-efficiency, further cutting down your energy spending. This can potentially save more than 50% of overall energy costs in a year.


Thanks to the compact design of the electric models, the 3000T models have a wide range of applications. You could use install them under the sink in the kitchen, placed at a corner in your garage, or even in your RVs and boats.

20-Year Lifespan

Bosch water heaters are built to withstand rust and scale. The high-quality materials and glass covering increases their durability, reliability, and average lifespan. A typical Bosch tankless water heater can serve you efficiently for more than 20 years.

Bosch Tankless Water Heater (2020 Review)


Tankless water heaters save you a lot in energy bills, fit into small spaces, and are built to last longer. This makes them advantageous than the traditional water heaters. Bosch tankless water heaters are some of the best in the industry, offering premium features like better performance, better durability, and Wi-Fi connectivity, too.


What is the benefit of a tankless water heater?
Benefits of a tankless water heater include up to 50% in energy savings, cleaner water, versatility, and longer lifespan.

Where do I install my tankless water heater?
Bosch tankless water heaters can either be installed under the sink, in a cabinet, mounted on the floor, or hung on the wall – depending on your choice. The exterior appearance is attractive and will add to the overall appeal of your home décor if hung in a visible place.

What is Intelligent Cascading?
Intelligent Cascading allows units to be joined together.

What is GPM in a tankless water heater, and why is it important?
The GPM (gallons per minute) represents the flow rate of the tankless water heater. It is a measure of how fast the heater works on the water and sends it to the tap.

Where are Bosch water heaters made?
While Bosch is a German corporation, Bosch Thermotechnology, which manufactures water heaters, has a division in Bosch USA. Bosch USA has its corporate headquarters in New Hampshire.