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Bosch is one of the most popular engineering companies in the world.

It is a multinational company founded in 1886 and currently headquartered in Gerlingen, Germany.

Industrial automation, power tools, security technology, thermo technology, and household appliances are some of the products and services offered by Bosch.

Bosch was established in North America in 1906 and is based in Farmington Hills, Michigan. The company excels in a variety of different field and is able to provide cross-domain solutions from a single source to its customers.

Over its years of operation, Bosch has employed renewable technologies to improve the energy efficiency of its products.

Bosch Tankless Water Heater Reviews


The tankless water heaters by Bosch can be widely classified into electric and gas types. These can be further classified into a number of series of products depending on the features they offer.

Let us take a look at the different model series of tankless water heaters produced by Bosch.

Now we shall discuss these models and their distinct characteristics in detail.

Greentherm 9000 Series

Bosch C 1210 ES NG 225,000 BTU Natural Gas Indoor Condensing Tankless Water Heater

The Greentherm T series from Bosch offers gas tankless water heaters that are available in different models for indoor and outdoor installation.

The series consists of condensing gas tankless water heaters with copper primary heat exchangers and stainless steel secondary heat exchangers. This series consists of models that have thermal efficiencies of more than 99%.

The different models in this series are T9800 SEO and T9900 SE. The T9900 models are meant for only outdoor installations, whereas the T9800 models are to be installed indoors.

Each of these two models is available in two different capacities. These models have separate units that can provide maximum flow rates of 11.2 GPM and 9 GPM.

These are residential models that have a maximum temperature setting of 120˚F. The heaters under this series can be field converted from natural gas to propane and vice versa.

These units are also heavily equipped with a lot of safety devices such as temperature and scaling detection sensors to ensure secure operation.

These models are equipped with an advanced but simple touch and a display screen that make them extremely user-friendly.

  • The excellent energy efficiency of more than 99% is provided by these models.
  • These models have an integrated Wi-Fi control feature that allows the user to monitor and control them remotely using their smartphones or tablets.
  • Comes with brackets for easy installation.
  • The advanced features in these units make their operation and maintenance simple as well.
  • Replacing tank-style units with these models is a simple process.
  • These units come with a built-in recirculation pump.
  • The models under this have high purchase prices.

Greentherm C Series

Bosch Greentherm C 950 ES NG Tankless Water Heater, Natural Gas

These are gas tankless water heaters that are meant for installation in places with moderate to warm climates.

The units contain high-quality copper heat exchangers that are capable of providing thermal efficiencies of 94%.

There are two models available in this series, namely, C950 ES and C1050 ES. The former is capable of producing a maximum flow rate of 13.1 GPM and the latter can provide up to 14.9 GPM.

These models feature high-efficiency Ceramat burners that improve the efficiency of operation.

These units come with several real-time diagnostic features and failure codes that make troubleshooting of these units a simple process. The heater also comes equipped with a freeze protection kit.

For indoor heaters, these units have vent terminations kits that make the venting installations easy.

These are powerful units that can be used for residential as well as commercial purposes with the help of a cascade kit.

  • These units are incorporated with several safety features for better maintenance procedures.
  • These units can be easily installed with the help of the wall hanging brackets that come with the units.
  • Outdoor units can be installed without using installation kits in areas where the average annual temperature is 15˚F.
  • These units have simpler features compared to the 9000 series. The 9000 series was launched to overcome the limitations of this series.
  • Cannot be used in regions where temperatures are constantly low.
  • Not meant for installation in manufactured homes and boats.

Therm Series

Bosch 830 ES NG Therm Tankless Water Heater, Natural Gas

The Therm series consists of a wide range of non-condensing gas tankless models that can be used for small, point-of-use applications to large whole-house applications.

Only one model in this series – C1210 is a condensing type unit.

The various sub-series in the non-condensing type include 330, 520, 830, and 940. Of these, 330 and 520 are available as indoor units only and are mainly applicable for single dedicated applications.

The energy efficiencies of these models are also not high.

940 is the largest non-condensing tankless water heater from Bosch with a maximum flow rate of 9.4 GPM. 940 and 830 models are available for installation outdoors as well as indoors.

The only condensing unit in this series is C 1210. This model has an energy efficiency of 98% and is the largest model available in this series.

This unit has can provide up to 12.1 GPM. This heater can be used for large applications or multiple application simultaneously.

  • Up to 24 units of the 1210 model can be cascaded for commercial applications.
  • The control boards of the Therm series are waterproof.
  • These units are capable of accurate and safe operations with good efficiency.
  • The wide range of models allows the user to choose one that is best suited to their hot water needs.
  • None of the units are Energy Star certified.
  • The non-condensing models are among the least efficient tankless units manufactured by Bosch.

Tronic Series

Bosch Electric Mini-Tank Water Heater Tronic 3000 T 4-Gallon (ES4)  - Eliminate Time for Hot Water - Shelf, Wall or Floor Mounted

Tronic series consists of electric tankless water heaters that are primarily meant for point-of-use applications. There are 3 sub-series and each has an energy efficiency of 98% with extremely low stand-by losses.

These sub-series are 3000, 5000, and 6000 respectively.

The 3000 series consists of US models and the 5000 and 6000 series consist of WH models. From the 3000 series, the maximum available flow rate is 2 GPM.

The 5000 series has only one model – WH36 which has a maximum flow rate of 6 GPM. The 6000 series has 2 models, WH17 and WH27, which have maximum flow rates of 3 GPM and 4 GPM respectively.

The Tronic 3000 units are ideal for point-of-use applications. The Tronic 5000 and 6000 units are capable of single or two bathroom applications as well as small whole-house applications.

The number in every unit represents the kW requirement of that unit. For instance, WH17 requires a 17 kW electrical supply.

  • These units are extremely energy efficient.
  • The Tronic 3000 consists of ultra-compact and lightweight units that can be installed in very small spaces.
  • These units have horizontal or vertical mounting options.
  • Indoor installation only. These units cannot be fixed in external spaces.
  • Not applicable for large applications and houses.


Although tankless water heaters are a very small portion of the vast range of products offered by Bosch, these units can easily compete with other brands that specialize in tankless water heating products.

Bosch is continuously improving their products and there are several features in their tankless water heaters that are not available in other brands.

The efficiencies of the tankless water heaters offered by Bosch are some of the highest in the market.

Although their initial prices are quite high, the quality and high performance of the units make them worth the user’s consideration.

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