Bosch Tankless Hot Water Heaters Review

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Explore the advantages of Bosch tankless hot water heaters. An expert review of gas and electric Bosch water heaters including popular series, Therm, Greentherm and Aquastar as the gas type, Powerstar and Tronic as the electric, all designed for residential applications and light commercial applications.

Bosch is a German manufacturer of HVAC products for residential and commercial applications, from 1886. In North America you can find several brands in tankless category, as mentioned above, while in Europe, Bosch tankless hot water heaters are known as Junkers. Keep in mind that Aquastar and Powerstar models are discontinued.

As you will see from the review below, the difference between new and old line of gas water heaters is that Greentherm and Therm new series are much more advanced, safe, reliable and durable, and with the greater energy savings.

Bosch Gas Tankless Review

Bosch Aquastar Review

bosch aquastar water heater 2400 es

While Bosch Aquastar water heaters are not in production any more, they are still available for purchase on some websites. As a reminder, this article will present a short review of the Aquastar models and its main features.

Aquastar tankless water heaters are wall-mounted gas appliances that utilize both natural gas and propane gas in residential and light commercial applications, where can be installed either indoor or outdoor.

The tankless technology, ensures the continuous water flow and on demand, while modulating gas valve allows stable hot water temperature with minimal fluctuations.

Aquastar models are designed in several sizes:

  • Bosch Aquastar 2700ES - is the largest model, and with the flow rate of 7.5 GPM is used for up to three applications.

  • Bosch Aquastar 2400ES - with the flow rate of 6.4 GPM, 2400 ES is ideal for homes with up to two baths.

  • Bosch Aquastar 1600 (H, P and PS models) - these are designed for providing hot water to one application as its water flow is low 4.3 GPM. Those who are looking for a gas water heater for point-of-use service, such as small apartments, small offices or cottages, these models are perfect. Aquastar 1600H is the unique product as it uses the hydro-generated ignition system, which makes it independent of the electricity.

  • Bosch Aquastar 1000

  • Bosch Aquastar 125

Bosch Therm Series Review

Therm series

Bosch Therm series is the new line of the advanced condensing and non-condensing tankless water heaters, which are replacing Aquastar models. The main difference is that the new line has several condensing models whose energy factor is ultra high, 0.95 vs. 0.82 found on conventional tankless models from Aquastar group.

Our focus will be on water heaters for residential use. Most of the models are non-condensing and they come with the power range from 74,900 to 199,000 Btu, while there are only three condensing models whose power is from 175,000 to 225,000 Btu. All models and its reviews are shown in the list below and via the appropriate links.

Bosch Greentherm Series Review

The Bosch Greentherm models are tankless and condensing water heaters that are operating with the ultra high thermal efficiency of over 94% and utilize several innovative features such as the modulating gas valve and intelligent electronics for the maximum performance, stability and reliability.

Bosch Electric Tankless Review

Bosch Tronic

Bosch Powerstar are electric tankless water heaters that are also discontinued as the above gas series Aquastar.

The new Bosch series of the electric tankless water heaters is called Tronic, also designed for the whole house and point-of-use applications. The largest model provide endless hot water up to 3 major applications.

See the reviews and prices on

Bosch tankless hot water heaters from above, with its advanced features and latest technology, are providing superior water heating, while saving the valuable floor space, lower the energy cost and provide the ultimate comfort with an endless supply of hot water.

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Here's a story from the great Canadian north. I live in Alberta where winter can be severe. About 10 years ago, I had a tankless Bosch water heater installed …

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Hi, I live in Montreal, Canada and I just bought the house with the Bosch tankless water heater, model 520 installed, which uses the hydro generator feature. …

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What do I have to do to protect my Bosch water heater from freezing during the winter time. I have try to winterize it but obviously I am missing something. …

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During a large remodeling project we purchased two Aquastar GWH2700 NATURAL GAS TANKLESS WATER HEATERS. After they were installed outside they froze and …

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I understand that the reviews for the Bosch hot water heaters are fairly poor and wish I had seen them before we purchased. We have a unit which doesn't …

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