Indirect water heaters are also often called the integrated water heating system or combination space and water heating system. This is mainly because they use the existing heating system of the house. Moreover, the working mechanism is pretty straight forward. Thus, the best indirect water heater does not require much maintenance.
They have proven to work really well without breaking for a prolonged period of time. The cold water is heated as it passed through the household heating system, particularly the heating coil. Sometimes, the water can be heated in a separately installed boiler that is usually placed adjacent to the household heating system.
Best indirect water heaters are used during the colder months of the year. That’s when the household heating system is being used throughout the house. Before buying and installing the best indirect water heater, think about whether you would want a traditional water heating system. That way, you could rely on it throughout the year even in warmer months.
Overall, indirect water heaters have been around for decades and are much easier to use. Additionally, with indirect water heaters, you would not have to worry about maintaining a stand-alone heating system. That would involve flushing the tubes and cleaning the heating coil, to say the least. Also, with the best indirect water heaters, you would only have to turn on the water tap.
There’s no need to wait for the water boiler to heat the water. Sadly, with indirect water heaters, you have less control over the temperature of the water coming out of the hot water tap. Obviously, if you have a large home and family then you need to look for a larger indirect water heating system that will be able to meet your needs.
Table of Contents
Comparison of 7 Best Indirect Water Heaters in 2021
| Image | Product Name | Features | Price |
|---|---|---|---|
 | Stiebel Eltron Tankless Water Heater |
| |
 | Rinnai Indoor Water Heater |
| |
 | Rheem Marathon Tall Water Heater |
| |
 | Westinghouse Water Heater |
| |
 | Triangle Tube Indirect Water Heater |
| |
 | Burnham Indirect-Fired Water Heater |
| |
 | EZ Supreme Tankless |
|
Top 7 Best Indirect Water Heater Reviews in 2021
1. Stiebel Eltron Tankless Water Heater
- Voltage: 208 V
- Wattage: 28.8 KW
- Temp. Range: 86°F – 140°F
- Water connections: 3/4″ NPT
When you see a nearly endless procession of five stars and lines and lines of praise about one single product, you know it has to be a great contender to be the best indirect water heater that’s available right now. And this Stiebel heater certainly takes the crown. There’s not a lot that an indirect water heater has to do to gain customer satisfaction.
It should heat water fast and hot enough, it should be a compact unit, and it should be easy to install and maintain. Does the Tempra 29 Plus model take care of all that? In short, it does. First of all, the thing that seemed to charm so many users is that it’s a small unit, but heavy and sturdy enough that the good quality shines through.
For such an efficient heater it also runs near silently. Moreover, the user interface on this heater is exceptionally friendly. A heater would not be a heater no matter how good it is if it doesn’t heat water well. Thankfully, this heats up water pretty well.
You might have to wait for 30-40 seconds for the water to heat up, but the flow and the volume of heater water are great, as seen in the indirect water heater reviews. As with any other device, this also has some small downsides. The installation is fast but might cost you a bit. The circuit board needs some adjustment to sit right. Also, the flow sensor is made of plastic, which leads to durability issues.
- Easy to use interface
- Runs very quietly
- Compact design
- Water gets super hot
- Easy and quick installation
- Reduced power consumption
- Flow sensor tends to wear down over time
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2. Rinnai Indoor Tankless Hot Water Heater
- Tank Capacity: 7.5 gallon
- Technology: Circ-Logic Capable
- Included: Valve Kit & Tankless Hot Water Heater
If you’re looking for a good, efficient, and high-performing indirect water heater, you can’t get it wrong with Rinnai. This Japanese multinational company makes heaters that are some of the best in the market, and so this heater has some of the best indirect water heater reviews.
Rinnai RL75IP is a tankless water heater that runs on gas and uses up so little fuel that you’ll notice a distinct drop on your gas bill. It heats the water up to 120℉, which is hot enough for showers and dishwashers. If you want it hotter, you might need to buy extra accessories with the heater.
To mention a few downsides, some customers complained about it making some noise. However, if it’s installed correctly, it should only make a negligible amount of noise when running. In a similar vein, let me advise you to get a professional to install this heater.
Although if you’re handy with machinery, you could install it yourself, and save yourself some money. Lastly, let me point out that Webstone service valves come included with the package, so don’t buy any extra when you’re buying parts to install it.
- Lowers gas bill
- High-performance indirect heater
- The low noise level when installed correctly
- Provides high water flow
- Equipped with Wi-Fi monitoring
- Doesn’t come with an auto-cleaning feature
3. Rheem Marathon Tall Electric Water Heater
- Voltage: 240 volts
- Efficiency: 0.90-0.94 EF
- Certification: GAMA/UL
- Recovery Rate: 20-Gallon GPH at a 90-Degree rise
A very easy to use an indirect water heater that is made from cast iron and is glazed in sleek silver color that will fit right in with any bathroom interior you have. Moreover, the manufacturer has used new technology that makes the heater weigh up to 40% lighter without losing its airtight heating coil compartment properties.
Plus, it features a great exterior paint finish that is easy to clean while the heater is large enough to quickly heat up enough water for a medium-sized household. The temperature is very easy to control and maintain as this heater has a built-in thermometer while the side thermostat makes controlling the temperature easily with the press of the bottom.
- Built-in thermometer
- Easy to control the temperature
- Made out of durable materials
- Beautiful design
- Lightweight and easy to install
- The exterior paintwork was reported to chip off with time
- Expensive
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4. Westinghouse Electric Water Heater
- Voltage: 240 volts
- Tank Capacity: 80 gallon
- Thermal Efficiency: 98%
- Recovery Rate: 90 degrees F is 20 GPH
Westinghouse 80 Gallon Indirect Water Heater is made from cast iron body and painted in the shiny silver finish while the interior is also made from cast iron and has been reported to be easy to clean with a soapy solution and hot water once in a while so as to prevent hard to clean build-up.
The temperature is very easy to control thanks to the thermostat and auto turn off once the needed temperature is reached hence you would not need to worry about the heater overheating. Plus, the manufacturer offers great customer service and lifetime technical support that has reported to be helpful and friendly.
Also, customers can choose from two different sized indirect water heater depending on the size of your home and family. Lastly, the lid can also be used to reach the heating coil for cleaning purposes during regular maintenance. The color of this best indirect water heater will fit right in plus it comes in a packaging box with a clear instruction booklet
- Compact yet big enough to store 80 gallons
- Lux silver design with a shiny exterior finish
- Warranty
- Easy to use and clear video installation instructions
- Good customer support
- Pricey
- The paint was reported to be easily scratched and scuffed
5. Triangle Tube Phase III Indirect Water Heater
- Self Cleaning: Yes
- Tank Capacity: 36 gallon
- Insulation: 2″ of Polyurethane foam
- Technology: Exclusive “Tank-in-Tank” Technology
This model of Triangle Tube Phase III indirect water heater is made with a much better water flow system than its previous Phase II version. As a result, this model is the best indirect hot water heater recommended by home improvement specialists.
Moreover, this Triangle indirect heater has a powder-coated finish that will ensure you can clean with ease. This device also makes use of a self-cleaning heat exchanger, therefore you wouldn’t have to worry a lot about cleaning or descaling it.
It is also really easy to install thanks to the clear instruction booklet included in the packaging box. More importantly, customers have noted how easy it is to maintain for years and years. I should also mention that the manufacturer offers a 2-year warranty and great customer support.
- Exclusive tank-in-tank technology
- Removable top for easy cleaning
- Hooks on the side for the electrical cord
- Great for medium-sized households
- Clear installation instructions
- There have been some concerns about leaking
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6. Burnham Alliance SL Hydrastone-Lined
- Coil included: Yes
- Tank Capacity: 35 gallon
- Other: Seamless hydrastone-lined tank
Burnham 35 Gallon Indirect Water Heater is made from durable materials and very thought through construction. Therefore, it will last for generations to come provided you pay attention to its maintenance and regularly clean the heating coil from buildup.
Subsequently, it is built from a triple-walled metal and 22 gauge steel. It easily retains heat but prevents it from escaping very quickly. Moreover, customers have reported that it quickly and evenly warms water for medium to large households.
Furthermore, testing of this best indirect water heater has revealed that it uses much less electricity as compared to other similar models. That is thanks to the construction and materials used thus it is much more eco-friendly and economical. Lastly, the exterior is powder-coated while the interior is porcelain finished for easy cleaning and maintenance.
- Durable cast iron and stainless steel construction
- Uses less electricity than other similar models
- Porcelain finish for easy cleaning
- Easy indoor installation
- The heating coil included in the packaging
- Available in one size only
- Some indirect water heaters reported arriving with scratched or scuffed surface
7. EZ Supreme Tankless Water Heater
- Tank Capacity: 100 gallon
- Natural Gas Model: 165,000 BTU
- Control: LCD control, Constant temperature
- Warranty: 1-year replacement warranty
Supreme White Indirect Water Heater will be great for small households plus, this heater has two hooks on the sides that can be used to store the electrical cord when the heater is not in use. Moreover, recent testing of this indirect water heater has revealed that it uses much less electricity as compared to other similar models thanks to the construction and materials used thus it is much more eco-friendly and economical.
Also, the exterior is powder-coated while the interior is porcelain finished for easy cleaning and maintenance. Furthermore, it is made from a rust-proof stainless steel body that has great heat retention and easy to clean.
Plus, this best indirect water heater comes with a thermostat that will help you regulate optimal temperature plus this model has an automatic turn-off option once the heater will reach its assigned temperature. Lastly, make sure the electrical cord is always stored properly because otherwise, you will risk it getting tangled and damaged in the process.
- Stainless body
- Great design that is easy to use
- Compact
- Built-in thermometer
- Affordable
- Provides Enough Hot Water For up to a 4 Bath Home
- Arrives without a handle or mounting hardware
- Comes without any manual or instructions
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Frequently Asked Questions (FAQs)
Q: Is It Cost-Effective to Buy an Indirect Water Heater?
A: Yes, it is. If you have a big-sized family that frequently uses a heater, you need an indirect water heater. Indirect water heaters can last for a long time, and they save you lots of money because they are energy-efficient.
Also, they have boiler systems, and they are fortified with an insulator- a thick polyurethane material that reduces heat loss by the hour. This feature helps to reduce the volume of energy used.
Q: How Does an Indirect Water Heater Work?
A: The water in the best indirect water heater passes through the inbuilt heat exchanger before it is taken to the inner tank. The energy is sapped from the boiler and the inner tank, making the indirect water heater super energy-efficient.
Q: What Differentiates a Direct Water Heater From the Indirect Model?
A: Direct water heaters come with an inbuilt boiler that heats the water, and they are bigger than the indirect model, having more parts too. In comparison, indirect water heaters use a boiler or a different furnace to heat the water. They do not have any inbuilt heating mechanism except for the heat exchange coil that draws heat from the outside burner to raise the water temperature.
Conclusion
Another thing that a potential buyer of an indirect household water heaters would definitely want to look at is how easy the heater will be to clean. Especially, you need to think about cleaning the heating coil which is located inside in the middle of the tank. Honestly, cleaning will always be the most daunting thing to do.
Porcelain and ceramic finishes are great because dust and dirt particles are less likely to stick to them. So, they can be easily cleaned with little effort and a mild soap solution. Although, they can easily scratch and scuff so you should be careful when handling them.
Additionally, it might make sense to regularly check the indirect water heater for any damages and leaks. Taking care of a problem immediately will save you from a lot of headaches. Why? Because leaving the problem to fester for a long time will only make things worse. Lastly, always look for the best indirect water heaters that come with a warranty and clear instructions.
You did not rate a Techtanium 40 Gallon Indirect Hot Water Heater. Why? Product issues? This is what my contractor is suggesting.