Bosch Tronic Electric Water Heaters
Review and Buying Tips
(updated 2017)

Bosch electric water heaters, named Tronic, are small and compact products, designed mainly for point-of-use water heating in residential and light commercial applications. Bosch electric models with more power and higher  water flow rate can be used for the whole-house water heating too. Explore the best models to buy and features to look for.

Bosch Tronic is designed to supply hot water to distant fixtures in the kitchen, bathroom or offices and where it is not economical to run long pipes from the central water heating system. Point-of-use water heaters are also used in cottages, apartments, pool houses or as a supplement for other systems, such as solar, or installed in line for one fixture. These are also called under-sink water heaters.

Model review

Bosch electric water heaters are designed in several sizes that are grouped in three categories; Tronic 5000 C / 6000 C, Tronic 3000 and Tronic 3000 T.

Bosch Tronic 5000 C / 6000 C

Bosch WH27 tankless whole house water heaterBosch WH27

This is the most powerful group of all Bosch electric water heaters. There are two series to choose from; Tronic 5000 C which has one but the largest model - WH36 and Tronic 6000 C with two smaller ones; WH27 and WH17, all designed with enough power and water flow to heat potable water efficiently and deliver to a single or multiple fixtures.

One of the advantages is the small, compact and lightweight design of maximum 26.5 lbs, making the handling and installation easier almost anywhere inside the house.

Another advantage is the modulating power on some models, so depending on the hot water demand, the unit can use more or less power, resulting in reduced temperature fluctuation and an increased comfort.

And when it compares to the tank-type units, Bosch electric water heaters also heat water with the high 97% efficiency, but this time heating is on demand, there is no storage tank and stand-by heat loss is minimal. Other quality features include the electronic flow sensor and the scale prevention technology, both working for the enhanced performance.

All three Tronic models work in the voltage range from 208 to 240, providing a power from 17.25 kW for WH17 to 36 kW for WH36 model, and water flow rate from 2.6 GPM to 5.4 GPM, suitable for homes with up to 3 showers.

Bosch Tronic 3000

Bosch Tronic 3000Bosch Tronic 3000

Bosch electric water heater from Tronic 3000 series are found in five sizes; US3, US6, US7, US9 and US12 - and are usually called under-sink water heaters as they are installed mainly in the bathroom or kitchen sink. With the smaller output and water flow, series 3000 is known as point-of-use group. The efficiency is little higher than on the previous models; 99% vs. 97%, while the flow rate is much lower; it goes from 0.5 GPM for US3 model to 1.8 GPM for the US12 model. Most models require voltage from 208-240 V while the model US3 120 V.

Electric water heaters from Tronic 3000 series utilize tankless technology for on demand water heating mainly to one fixture. The models are small and lightweight, equipped with the copper heat exchanger and heating elements, where only the model US12 features the thermostatic control. Another difference from the above whole-house models is that 3000 series allows installation horizontally or vertically.

Tronic 3000T

Bosch Tronic 3000T water heaterBosch Tronic 3000T

The last category of the Bosch electric water heaters is the Tronic 3000T, a group that consists of the three models; ES 8, ES4 and ES2.5. As opposed to the above electric and tankless models, Tronic 3000T utilizes a small storage tank where hot water is always ready to be delivered fast to the fixture. It can be used as the stand alone or in recirculation systems reducing the wait time for hot water delivery.

All the 3000T electric heaters have a compact and lightweight design,with the  maximum size of approximately 17x17x14” and weights close to 30 pounds, for easy installation either on the wall or mounted on the floor. 

Tronic 3000T uses one 1440 W heating element for easy hot water supply mainly to one fixture with the maximum temperature of 145 F, while the largest model ES 8 can be used for delivering hot water to 2 sinks at a time. Also, model ES8 is hardwired, requiring some hands-on skills for installation, while ES4 and ES2.5 are simpler plug-in type.

Bosch electric water heaters from Tronic series are sold in the US and Canada, except the group 3000T that is sold in America only. The warranty is 6 years for tank-type heaters, while the tankless come with the 5 years only.

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