Choosing a Bosch gas tankless water heater as a replacement makes sense – here’s why:
If you’re in the market for a new water heater to replace an existing hot water tank, you should have a look at a Bosch gas tankless water heater.
In this line, you get Bosch quality design and construction, a quicker, easier installation, plus – hassle-free operations and maintenance.
For added peace of mind, Bosch also offers a 3-15 year warranty depending upon how it is used.
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Hot Water At the Ready – From A Compact Bosch Gas Tankless Water Heater
What you get with the Bosch tankless water heater is a space saving design that looks every bit as modern and efficient as it actually is. In this brief article, we’ll discuss the gas models. Plus, I will let you compare the electric models also.
Here Bosch deploys condensing technology to create an super-efficient tankless water heating system that are among the most energy efficient in the industry. All gas models are Energy Star approved and can produce enough hot water for a minimum of two to three major faucets at the same time.
Bosch Gas Tankless Water Heater Comparison Table
| Model | Key specs | Best for | Details & Amazon |
|---|---|---|---|
Bosch Therm 520 HN NG Natural Gas Tankless Water Heater Top Pick | Key specs 117,000 BTU max input, 80% efficiency, hydro‑power ignition (no electricity), supports up to 2 fixtures. | Best for Homes, cabins, or off‑grid setups needing hot water even during power outages. | Details & Amazon The Therm 520 HN NG is Bosch’s most consistently available gas tankless model on Amazon. Its water‑powered ignition eliminates the need for electricity, making it ideal for remote locations or areas with unreliable power. A proven whole‑home performer for small to mid‑size households. |
Bosch Therm 830 ES NG Tankless Water Heater Best Value | Key specs 175,000 BTU input, condensing‑style efficiency, supports multi‑fixture use. | Best for Mid‑size homes needing strong flow rates at a lower price point. | Details & Amazon The 830 ES NG is a long‑running Bosch gas model known for durability and solid whole‑home performance. Availability on Amazon varies, but when in stock it’s one of the strongest value picks in Bosch’s gas lineup. |
Have It Installed For You
It is always recommended that with a whole house water heater, that you use a certified professional for installation. It’s also a must should you ever have a warranty claim. The problem for the handy do-it-yourselfer is it looks awful tempting to just go ahead and install it yourself.
But for the warranty to be valid, your Bosch heater must be installed by trained and certified installer, service agency, or gas supplier.
If you install it yourself – something plenty of DIY types are certainly capable of doing – your warranty may be deemed null and void. In our opinion, it’s not worth the risk. Hire a competent professional and enjoy the peace of mind in knowing the job is done right and you’re fully protected.
Professional Installers Love These
Pros who install water heaters all day long tend to love the Bosch series because they’re fairly quick and easy to install – particularly when they’re replacing an existing water heater unit – whether it’s a hot water tank or a tankless system.
What makes it a favorite among pro installers are the readily accessible water connections on top of each unit, plus the integrated drain ports that are built-in, so isolation valves are not required. What this boils down to is that these Bosch tankless water heaters take less time to install correctly than other competing brands and models.
There’s also a built-in sensor that automatically calibrates water heating operations, which makes switching to a tankless water heater that much more painless for homeowners.
Bosch Electric Tankless Water Heaters Comparison Table
Somewhere on this list is the ideal Bosch electric tankless water heater system for you. It doesn’t really matter whether you’re using this in a house, townhouse, condo, or large commercial project. There’s a Bosch water heater that will do the job.
| Model | Key specs | Best for | Details & Amazon |
|---|---|---|---|
Bosch Tronic 6100 Electric Tankless Water Heater, 27 kW Top Pick | Key specs 27 kW output, self‑modulating, compact wall‑mount design, supports multiple fixtures. | Best for Small–mid homes needing tank‑replacement performance with stable hot‑water flow. | Details & Amazon Bosch’s strongest electric tankless model delivers whole‑home performance with excellent temperature stability. Ideal for replacing a traditional tank while saving space and energy. |
Bosch Tronic 6100 Electric Tankless Water Heater, 18 kW Best for Small Homes | Key specs 18 kW output, electronic temperature control, slim installation profile. | Best for Cabins, apartments, or compact homes needing 1–2 simultaneous fixtures. | Details & Amazon A balanced whole‑home option offering strong performance without requiring oversized electrical service. Great for showers plus sinks in smaller residences. |
Bosch Tronic 4000 Electric Tankless Water Heater, 8.5 kW Best Value | Key specs 8.5 kW output, under‑sink install, supports a shower in warm climates or multiple sinks. | Best for Budget upgrades needing instant hot water at a bathroom or studio. | Details & Amazon A strong performer for point‑of‑use applications, offering fast hot water with excellent efficiency. Ideal for bathrooms or small living spaces. |
Bosch Tronic 4000 Electric Tankless Water Heater, 6.5 kW Best for Single Sink | Key specs 6.5 kW output, ultra‑compact, optimized for one sink. | Best for Guest baths, utility sinks, garages, or hand‑washing stations. | Details & Amazon Designed for true point‑of‑use performance, this model eliminates long waits and wasted water by heating directly at the tap. |
Bosch Tronic 4000 Electric Tankless Water Heater, 3.5 kW Best for Handwashing | Key specs 3.5 kW output, ultra‑compact, ideal for low‑flow fixtures. | Best for Powder rooms, garages, workshops, or any single faucet needing warm water fast. | Details & Amazon Bosch’s smallest tankless model is perfect for hand‑washing stations where space is tight and warm water is needed instantly. A simple, efficient upgrade for remote sinks. |
What Every One Of The Bosch Tankless Water Heaters Offers
- Water connections on top of the unit for easier tank replacement
- Auto-tuning for better performance automatically
- Integrated flush ports (these drain ports on the bottom eliminate the need for expensive isolation valves)
- Space-saving compact design
- High-resolution color LCD user interface
- Ultra efficiency
- Wi-Fi accessibility (with free downloadable app from Bosch)
- Integrated freeze protection
- Stainless steel heat exchanger (This helps minimize scale buildup and since stainless steel lasts longer than copper, you can rest assured that you’re getting a water heater that is well-built with quality components, so it should last a long time)
Indoor and Outdoor Versions
Some are meant to be installed outdoors and the others inside. A few of them boast an integrated pump for hot water recirculation and instant delivery instead of the usual delay you get with most tankless water heaters on the market.
Indoor models can be converted from natural gas (NG) into liquid propane (LPG). Right out of the box, they are all made to be connected to natural gas lines. But if you prefer liquid propane – conversions can be done on indoor models, according to the manufacturer.
Numerous options exist for venting, making most installations somewhat straightforward and relatively simple.
Reliability and Stability
Most people who choose a Bosch tankless water heater are looking for something that’s more reliable than their current tank-type water heater. Of course, energy efficiency is another key component, since the more efficient any device is, the less it costs your to operate over the long term.
Easy To Accommodate
Since these Bosch units are tankless systems, you can fit them in pretty well anywhere. Most people who are replacing an aging tank are amazed at how little space these tankless models occupy – and the new found space they acquire.
Small – But Sophisticated
For such a small piece of equipment (relative to any hot water tank) these Bosch water heaters seem much more modern and sophisticated. And most people are surprised at how straightforward the setup is it, In fact you’ll probably find that it’s as simple as connecting the old type of tank heater.
If there is a more time-consuming element to the installation, it typically is running the intake and exhaust lines properly. But if these are already in place, you’re golden.
Customers are thrilled at the instant hot water that they get at the tap – hot water that seems to flow endlessly. They also appreciate that there’s not a lot of settings that need to be adjusted once you get your water temperature set the way you like it. It’s basically a hassle-free operation.
And the real beauty of these whole home systems is that you can use multiple taps at once. Just how many and how fast and furious they flow depends on the model and how much you need to increase the water temperature from the source to the tap. Each model is a little different in this regard. So select the one that best meets your needs.
Feature Rich At A Reasonable Price
A Bosch gas tankless water heater offers a lot of useful features built-in, and they do so at a competitive price. Primarily designed for residential applications, this series can deliver hot water up to 140°F at a 9 gallon per minute rate of flow with a 35°F rising temperature required.
The bottom line is this: The Bosch gas tankless water heater represents good value for the buyer. All models run on 120 volts (besides the gas) and can therefore be plugged into any normal household outlet. Although, you should always have a dedicated outlet for your hot water heater. This simple plug-in set-up helps avoid the challenges involved with any sort of direct wiring.
These models offer up to a maximum of 11 gallons per minute of hot water at a temperature increase of 35 degrees. They vary between 160,000 BTU in 199,000 BTU. Thermal efficiency measures a stellar 99%. What makes these Bosch gas tankless water heaters so awesome is that they are whole-house water heating systems. So they are designed to provide plenty of hot water on demand – without any interruptions.
All models can deliver water at 100 to 140°F. Temperature settings – whether via the digital display or your smart phone – are accurate and easy to read.
Each Bosch tankless also comes equipped with automatic tuning and freeze protection – so you can enjoy optimal performance over the long haul, no matter what the weather happens to be where you live.
Another interesting point is that the average life expectancy on these tankless water heaters is about 20 years- give or take. That’s notably higher than most tank-based water heaters can provide.
How Much Flow Do You Need?
When factoring in how much water flow you’ll actually need (and therefore which model to choose) consider the following typical scenarios:
Bathroom Sink Faucet: 1 to 1.5 Gallons Per Minute
Kitchen Faucet: 2 to 3 Gallons Per Minute
Shower: 1.5 to 3 Gallons Per Minute
Dishwasher: 2 to 4 Gallons Per Minute
Washing Machine: 3 to 5 Gallons Per Minute
How Can You Measure Your Existing Water Flow?
To determine the water flow rate you may require moving forward, it’s important to measure the rate of water flow you currently have at each fixture. If you plan on using multiple faucets simultaneously, you need to add the flow from each, giving you a total flow. This number will indicate the maximum flow rate required in your new water heater.
To do so, record the fill times at each faucet using a large half- gallon or gallon container. You’ll need to know the volume to get an accurate measurement. For example, if you can fill a 1 gallon jug in 30 seconds, you’re getting a flow rate at that specific faucet of 2 gallons per minute.
Check The Ground Water Temperature In Your Area
It’s also important to know the average groundwater temperature in your area. Please refer to the map below. This will help you determine how much of a increase in water temperature is required. The greater the difference between the ground (or inlet) water temperature water and the temperature you desire in the shower – the more energy necessary to heat it and the lower the volume that flows.
The Verdict
In our opinion, any one of these Bosch gas tankless water heaters would be an excellent solution for providing abundant hot water in an energy efficient manner.
For new homes, you’ll be equipped with a quality system from the get-go. And if this is a replacement purchase, you’ll be astounded by the difference it makes.
As a result, you will save not only space but money and time too – plus the unnecessary stress that can develop when you have a water heater that is less than reliable.
Bosch whole house tankless water heater reviews.
Bosch Electric Mini Tank Water Heater Review
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