Bosch Tronic Electric Water Heaters
Review and Buying Tips

Bosch electric water heaters from the Tronic series 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 a higher water flow rate can be used for whole-house water heating. Explore the best models to buy and features to look for.

Bosch Tronic heaters are 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 grouped into 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 models are designed with enough power and water flow to heat potable water efficiently and deliver hot water to a single or multiple fixtures.

One of the advantages is the small, compact, and lightweight design of a maximum of 26.5 lbs., making 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 increased comfort.

When compared to the tank-type units, Bosch electric water heaters also heat water with a high 97% efficiency, but this time heating is on-demand, there is no storage tank, and standby 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 power from 17.25 kW for WH17 to 36 kW for the 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 heaters 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 the point-of-use group. The efficiency is a little higher than on the previous models; 99% vs. 97%, while the flow rate is much lower; it goes from 0.5 GPM for the 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 the 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 the 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 so that it can be delivered to the fixture fast. It can be used as a 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 a maximum size of approximately 17"x17"x14" and weigh 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 the simple plug-in type.

Bosch electric water heaters from the 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 comes with 5 years only.

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