I first encountered Bosch tankless water heaters when a client wanted to replace their old, bulky water heater with something more energy-efficient and space-saving. Bosch has been around for a while, and their reputation for German engineering intrigued me. After installing a few different models, I had the chance to see how well these units performed under real-world conditions. Spoiler alert: Bosch doesn’t disappoint.
In this review, I’ll break down the top Bosch tankless water heater models, their pros and cons, and whether they’re the right choice for your home.
Why Go with Bosch Tankless Water Heaters?
Bosch tankless water heaters are known for being highly energy-efficient, compact, and durable. Instead of keeping a tank of water heated all day, a tankless system heats water only when you need it. This can save you a significant amount on your energy bills, especially if you have a busy household with varying hot water demands.
The Bosch models I’ve installed deliver consistent performance and come with features that make them some of the most reliable units on the market.
Top Bosch Tankless Water Heater Models
| Model | Fuel Type | Flow Rate | Efficiency Rating | Warranty | Ideal For |
|---|---|---|---|---|---|
| Bosch 940 ES | Natural Gas/Propane | 9.4 GPM | 0.92 EF | 15 years (heat exchanger) | Large homes with multiple water demands |
| Bosch 830 ES | Natural Gas/Propane | 8.3 GPM | 0.83 EF | 15 years | Medium to large homes |
| Bosch Therm 520 HN | Natural Gas | 5.3 GPM | 0.79 EF | 12 years | Small to medium homes |
| Bosch Tronic 3000 US12 | Electric | 1.8 GPM | 0.98 EF | 5 years | Point-of-use applications (bathroom, kitchen) |
1. Bosch 940 ES Tankless Water Heater
If you have a large home and need a lot of hot water simultaneously, the Bosch 940 ES is a great option. I installed one of these in a 4-bedroom, 3-bathroom home where the family needed hot water for multiple showers, laundry, and the kitchen—all at the same time.
Key Features:
- High Flow Rate: With a 9.4 GPM (gallons per minute) flow rate, this unit can easily handle multiple fixtures simultaneously.
- Energy Efficient: It has an Energy Factor (EF) of 0.92, which means it’s 92% efficient. This helps cut down on energy consumption compared to a standard tank heater.
- Durability: The heat exchanger comes with a 15-year warranty, which speaks to the build quality and reliability of this model.
- Environmentally Friendly: This unit is low-NOx, meaning it produces fewer harmful emissions.
Pros:
- Excellent for large homes with high hot water demand.
- High efficiency and low operating costs.
- Durable with a long warranty.
Cons:
- Price: It’s on the higher end for a tankless water heater.
- Installation Complexity: This model is more complex to install and may require professional installation, especially for homes that need venting upgrades for gas models.
2. Bosch 830 ES Tankless Water Heater
The Bosch 830 ES is a step down from the 940 ES but still powerful enough for medium to large homes. I’ve recommended this model to clients who don’t quite need the capacity of the 940 ES but still want reliable performance for a family of 4-5.
Key Features:
- Flow Rate: With 8.3 GPM, this model can handle 2-3 fixtures simultaneously without running out of hot water.
- Energy Efficiency: It has an EF of 0.83, making it slightly less efficient than the 940 ES, but still a great performer for its class.
- Durability: Like the 940 ES, it comes with a 15-year heat exchanger warranty, so you know it’s built to last.
- Compact Design: The 830 ES is much more compact than a traditional water heater, saving space in your home.
Pros:
- Great for medium-sized homes.
- Very reliable and energy-efficient.
- Compact and space-saving.
Cons:
- Lower Efficiency: The EF is lower compared to the 940 ES, which means slightly higher energy bills.
- Water Flow Drop: If multiple fixtures are running at the same time, the flow rate can drop.
3. Bosch Therm 520 HN Tankless Water Heater (Non-Condensing)
For smaller homes or apartments, the Bosch Therm 520 HN is a solid choice. It’s a non-condensing unit, meaning it’s not as efficient as the Bosch condensing models, but it’s still reliable for homes with lighter water demands.
Key Features:
- Flow Rate: At 5.3 GPM, it’s perfect for smaller homes with 1-2 bathrooms or point-of-use applications.
- Standing Pilot Light: This model uses a pilot light instead of electric ignition, which makes it a bit less efficient but useful in areas where power outages are common.
- 12-Year Warranty: A decent warranty on the heat exchanger gives peace of mind for longevity.
Pros:
- Ideal for small to medium homes.
- Compact and easy to install.
- Lower price point compared to larger models.
Cons:
- Lower Efficiency: With an EF of 0.79, it’s less efficient than the Bosch condensing models.
- Pilot Light: The standing pilot light means it uses a small amount of gas even when not in use.
4. Bosch Tronic 3000 Electric Tankless Water Heater
The Bosch Tronic 3000 US12 is a point-of-use electric tankless water heater designed for small, specific applications like sinks, bathrooms, or kitchens. I’ve installed this in homes that needed instant hot water for a particular fixture without heating a whole tank.
Key Features:
- Flow Rate: It delivers up to 1.8 GPM, which is sufficient for a single sink or bathroom.
- Energy Efficiency: With an EF of 0.98, it’s almost 100% efficient, meaning nearly every bit of electricity used goes to heating water.
- Compact Design: Its small size makes it perfect for under-sink installation or tight spaces.
Pros:
- Highly efficient for point-of-use applications.
- Compact and easy to install.
- Inexpensive upfront cost.
Cons:
- Limited Capacity: Not suitable for whole-house use.
- Flow Rate: Can only support one fixture at a time.
Pros of Bosch Tankless Water Heaters
- Energy Efficiency: Most Bosch models are highly efficient, with condensing models reaching up to 0.92 EF. This means more savings on energy bills, especially if you have a high hot water demand.
- Durable and Reliable: Bosch’s German engineering is well-known for durability. Most of their tankless models come with long warranties, especially on the heat exchanger (up to 15 years).
- Compact Size: Whether it’s a small electric point-of-use model or a large natural gas model, Bosch water heaters save a significant amount of space compared to traditional tank water heaters.
- Environmental Friendliness: Many Bosch models are low-NOx, meaning they emit fewer pollutants than standard gas heaters, which is a huge bonus for eco-conscious homeowners.
Cons of Bosch Tankless Water Heaters
- Higher Upfront Costs: Bosch tankless water heaters tend to be on the more expensive side. However, the long-term savings on energy can make up for the initial investment.
- Installation Complexity: For gas models, installation can be tricky and may require professional help, especially with venting requirements and gas line upgrades.
- Flow Rate Drops: In some of the smaller models like the Bosch 830 ES, you might notice a drop in water pressure if too many fixtures are in use simultaneously.
Final Thoughts: Is Bosch the Right Tankless Water Heater for You?
If you’re looking for a durable, energy-efficient, and compact water heating solution, Bosch tankless water heaters are definitely worth considering. The Bosch 940 ES is a powerhouse for larger homes, while the Bosch Therm 520 HN and Bosch Tronic 3000 are excellent choices for smaller setups.
The initial cost may be higher compared to other brands, but the long-term energy savings, reliability, and space-saving design make Bosch tankless water heaters a smart investment. Plus, with their strong warranties, you can count on them to deliver hot water for years to come.
For a busy family or eco-conscious homeowner, Bosch offers some of the best-performing tankless water heaters on the market today.