Best Bosch Hot Water Heater

Aquastar 2700ES, Aquastar 1600H and
Therm C 1210 ES Review

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So, what is the best Bosch hot water heater for your residential water heating needs? Is it a heater from Aquastar series 125, 1600, 2400, 2700; or a tankless gas model from Therm series? Let's find out.

What to look for when searching for the best water heater

In order to find out which is the best tankless water heater from Bosch, we have reviewed every single gas unit Bosch has to offer. We used the following criteria and directions in choosing the best Bosch model:

  • What are the most advanced and useful features, Bosch tankless water heater has to offer?

  • The best Bosch tankless heater is one that provides savings on gas, uses green technology and contributes in the reduction of greenhouse gases.

  • Does the unit provide an innovative design?

  • What are the specifications?

  • The best Bosch hot water heater has to provide flexibility in installation.

  • The water heater has to be versatile so it can work in different applications.

Once the best Bosch hot water heater is chosen, I will do the detail review; see what it has to offer, what are your benefits there, how much money does it cost and show the summary of what other users are saying.

I will also review Bosch heater's specification for every single gas tankless water heater, does it provide enough hot water for a family of 4, as the standard family size, and can it support hot tubs and multiple applications.

The Best Bosch Tankless Water Heater is...

In this article about the best Bosch hot water heater, I have found few gas tankless models, which are per my opinion, worth being the best.

Bosch 1600H is an affordable heater with great and unique features and I have included it for budget oriented families. Bosch hot water heater from the 2700 series is the best of all the available models of Aquastar series, but is expensive. These two models, which are reviewed below, are coming from the Aquastar series, while the condensing model, which will also be reviewed, is from the new Therm series.

Aquastar 1600H review


aquastar 1600h with the hydro-generatored feature

Bosch Aquastar 1600H model is the best Bosch water heater in the category of cheap or budget friendly models.

I personally like Bosch Aquastar 1600H model as it is affordable and offers an innovative technology, using the energy from the water flow to ignite the spark. This is called hydro-generated ignition where the small turbine is used to generate the electricity.

The patented feature allows the water heater to operate without a standing pilot, electricity, or a battery. Similar model from newer Therm series is a model Therm 520 HN.


The disadvantage is that it provides only 4.3 gallons per minute of hot water, which is enough for one bath home only. Too bad, as many modern homes, with standard family size have two bathrooms. Also, it doesn't offer the display panel on the front cover, which is very beneficial to monitor the temperature and to diagnose if there is a problem.

As it has only 0.8 EF, energy factor, Bosch Aquastar 1600H is not qualified for Energy Star, or high efficiency recognition. That means no government tax breaks.

User Reviews

  • Bosch hot water heater 1600H provides decent savings when compare to the standard tank type water heaters.

  • This Aquastar model is easy to install; it provides hot water fast, runs quiet and smooth.

  • Minimum pipe size for maximum performance is a must. Otherwise, you will not have the water hot enough.

  • It requires a minimum flow to operate. If you have a screen on the faucet you might have to remove it. It doesn't work well with the flow restrictors.

  • Hot-cold sandwiches when the water flow inside the home plumbing fluctuates and when the unit turns off often. It has to be reset it manually.

The price

You can buy Bosch Aquastar 1600H model online for approximately $700, as brand new, or $400 factory-reconditioned.

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Aquastar 2700ES review


bosch aquastar 2700 es

Aquastar 2700ES model, is the best Bosch water heater from this series, and top of the line tankless model.

2700ES model is the wall mounted, power vent model that allows flexible installation with the horizontal and vertical venting. This is an indoor unit, but with a purchase of the outdoor installation kit, 2700ES heater can be installed outdoors also.

The unit is approved for installations up to 8000 ft.

Bosch Aquastar 2700ES uses the electronic ignition, has a powerful burner, sealed combustion chamber, is equipped with a primary fan, mixer, and secondary fan, for better water heater performance and efficiency, so it can meet the Energy Star requirements. This is a high efficiency, eco-friendly heater, which operates with the reduced NOx gases.

With its 7 gallons per minute of hot water, Bosch Aquastar 2700ES is designed to supply your shower, washing machine and dishwasher simultaneously, and even for variable flow applications.

One of the great features 2700ES offers is the LCD display. It shows the temperature, you can set the temperature, it has a flame indicator, power bar indicator, error indicator; you can use it to measure CO2, but with the installed combustion cover, to program the unit, control board diagnostics, fan speed adjustment and troubleshooting.


Aquastar 2700ES model, as the best Bosch hot water heater with the sophisticated technology, is also the most expensive one. You have to pay $400 more that what would you pay for Bosch Aquastar 1600H model. The price range is between $1100 and $1500, depends on the store.

User Reviews

  • One of the complains was that Bosch Aquastar 2700ES didn't perform well in colder climates.

  • Hard to find replacement parts.

  • Expensive vent kit.
  • Silent and space saver.

  • Plenty of hot water.
  • Expensive unit.

  • Great on gas.
  • Easy installation with many options.

  • This product qualifies for up to $1500 Federal Tax Credit (30% of purchase and installation).
  • 2700 ES is eligible for rebates from the utility company.

  • It is not that good for hand-washing and short bursts.

Bosch Therm C 1210 ES review

Bosch Therm C 1210 ES

Bosch Therm C1210 ES is the gas and condensing tankless water heater, which comes with the highest efficiency and performance of all models from Therm and Aquastar series.

The condensing technology is what makes this Bosch hot water heater unique as it increases its efficiency and lowers the emission of greenhouse gases. After reviewing all its features I can say that Therm C1210 ES is the best Bosch hot water heater.


  • ASME certified - complies with the relevant standards and specifications.

  • Ultra efficient water heating with over 94% efficiency.

  • Cheaper vent pipe is used (such as PVC or CPVC), as the water heater releases gases with the lower exhaust temperature.

  • Up to 24 units can be linked into one system for high demanding homes or commercial applications.

  • Flexible installation; vent pipe can run horizontally or vertically by using the vent system wit the concentric or two separate pipes.

  • Suitable for heating potable water and living space.
  • Great warranty of 15 years.


  • High initial costs that includes the prices and installation.

Features and specs

  • LCD display with the power bar, temperature, error code, flame, solar mode and remote control indicators.

  • Program button (to adjust the temperature, fan speed...)

  • The diagnostic system with the error codes for easy troubleshooting and fixing. Diagnostic menu also shows the fan speed, temperature, power, water flow and other important parameters.

  • 225,000 Btu gas input.

  • 12.1 gallons per minute water flow rate.

  • Low minimum water flow needed for activation - 0.5 GPM.

One is for sure: the best Bosch hot water heater is usually the most expensive, which also uses the latest technology, materials and the most advanced features.

My recommendations, based on the experience in water heating, is to go with one that meets the demand, provides flexible installation and offers modulation for steady work and reduced temperature fluctuation... everything else is extra. If you are budget oriented, buy a 1600 series (or newer Therm 520 HN); if looking for more gadgets, any Energy Star model (2700 or 2400 series) is good enough.

For those who prefer top of the line water heater, which utilizes the condensing technology, heats the water with the ultra high efficiency and low heat loss, is green or environmentally friendly, the above Therm 520 HN as the best Bosch hot water heater, is the perfect choice.

(Pictures courtesy of Bosch)

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