Best Indirect Water Heater for Your Home in 2022


Best Indirect Water Heater Img

So you’ve decided that you want the best indirect water heater for your home. But now what?

Well, there are many reasons to install an indirect water heater.

First, it provides hot water on demand, which means there are no standby losses for fuel or electricity. Also, you no longer have to worry about the inconvenience of waiting for your hot water to reach your faucet or running out of hot water in the middle of a shower.

But tell you what, there are so many different types of indirect water heaters on the market, each with unique pros and cons.

So, how do you know which heater is best for you?

That’s where this article comes in! We’re going to go into detail about 10 of the best indirect hot water heater units available today. Also, we’ll cover all of the important considerations when purchasing an indirect water heater for your home.

10 Best Indirect Water Heater Reviews

Table of Contents

1. EcoSmart ECO MINI 2.5 Electric Mini-Tank Water Heater

Sometimes, good things come in small packages. The same is true for the ECO MINI 2.5 electric water heater.

This indirect water heater allows you to enjoy endless hot water without bulky heaters.

EcoSmart ECO MINI 2.5 Electric Mini-Tank Water Heater Img

Yes, you heard it right. This nifty water heater weighs only 17.6 pounds. And would you believe? It measures only 17 x 10.94 x 10.91 inches.

The benefit of such a small, sleek size is that it can fit virtually anywhere, at home or in the office. Also, it’s a breeze to mount on the wall with little to no complications.

Nevertheless, it dispenses 2.5 gallons, enough for booster and point-of-use applications. Such capacity also means it can run two faucets and a shower simultaneously.

Did you know that ECO MINI 2.5 is also many times more energy-efficient than your average electric tank heater?

Yes, this heater has 99.8% energy efficiency. So, it not only provides optimal heating but also reduces your electricity bills significantly.

The temperature is adjustable from 50-140 degrees Fahrenheit. In addition, it has a digital temperature display that indicates the temperature of the water coming out.

Unlike other electric heaters out there, ECO MINI 2.5 saves you the frustrations of a hardwired installation. Instead, it plugs into your standard 120V outlet, eliminating the need for an electrician.

The package includes an extra-long cord so you can take it just about anywhere you need it to go. What’s more, you’ll get a bracket for floor or wall mounting. However, you’ll need additional parts to complete the installation.

With the ECO MINI 2.5, you’ll feel reassured that you’re getting a durable product with single weld construction. Also, it includes 6-year leak protection and 2-year parts warranty for your peace of mind.

For your attention, this water heater works with ½-inch top-mount water connections.


✅ Lightweight and compact

✅ 99.8% energy efficient

✅ Digital temperature display

✅ Easy plug-in installation


✖️ Requires additional parts when installing

2. Reliance 6 6 SOMS K – 6 Gallon Compact Electric Water Heater

Reliance 6 6 SOMS K water heaters offers smart, practical design for reliable heating.

It’s a 6-gallon heater, small enough that it doesn’t take too much space. At 14 inches in diameter and 15.25 inches tall, you can tuck it under cabinets or squeeze it into tight spaces.

Reliance 6 6 SOMS K – 6 Gallon Compact Electric Water Heater Img

In addition to the compact size, this water heater has side-mount plumbing. So, there’s nothing much coming in the way of your pipes, making it even better for tight spaces. However, it also includes optional ¾-inch top-mount connections.

So, how much are 6 gallons?

Well, such size works well for most homeowners looking for a small water heater. Moreover, it’s just the perfect size for RV or mobile homes. Also, it works perfectly for a recirculation setup.

This water heater also uses 1650 watts copper heating element for fast heating and temperature recovery. Plus, it meets NAECA codes. So now, you can enjoy more hot water while using less energy.

What’s more, Reliance 6 6 SOMS K has 1-inch foam insulation. For this reason, it retains more heat.

Also, this electric heater stands out because of its long life. For instance, it has built-in anode rods that prevent any possible corrosion. Not to mention this water heater has a glass-lined tank for additional durability.

The installation is pretty side. Even better, the unit comes with factory-installed temperature and pressure relief valves for safe use.

You can purchase a cord for plug-in installation. But, conversely, you can hardwire it – whatever is easier.

Another benefit of buying this water heater is that it comes with a generous warranty. You get a 6-year warranty that covers both parts and tank failure.


✅ Compact and space-saving

✅ Resistant to corrosion

✅ Easy side-mount plumbing

✅ Meets NAECA codes


✖️ A bit difficult to change to the top fittings

3. American Standard CE-12-AS 12-Gallon Point of Use Electric Water Heater

Are you looking for the best indirect water heater that assures you of a compact design without being overly small? If so, consider the American Standard CE-12-AS water heater.

This 240V electric water heater is 15.88 inches wide and a bit taller at 21.88 inches. Still, 21 inches is low enough for tucking under cabinets.

American Standard CE-12-AS 12-Gallon Point of Use Electric Water Heater Img

Like Reliance 6 6 SOMS K, this water heater includes both side and top-mount water connections. Hence, it offers flexible installation, especially in tight spots.

But while small, this water heater has a 12-gallon capacity. It isn’t much for a family with high hot water demand. However, it’s enough for couples or RV use.

This immersion heater draws only 1500 watts. Yet, surprisingly, it heats as fast as most 4800 watts models, making it perfect for rapid hourly hot water recovery.

For your attention, this unit generates over 71,600 BTUs per hour with a recovery time of just over half an hour. Also, it offers variable temperature control of up to 160 degrees Fahrenheit.

This electric water heater also prides itself on the longevity of its tank.

Firstly, it has a heavy-gauge steel interior enameled in a fiberglass filler. Secondly, the tank has life-long anode rods. Such a combination offers ultimate protection against corrosion.

Moreover, the tank offers easy maintenance.

It has a brass drain, which helps prevent sediment buildup. For this reason, it makes maintenance easier and helps increase the tank’s lifespan.

Also, American Standard ensures that this electric water heater meets all criteria. For instance, it complies with NAECA and Energy Efficiency requirements. In addition, it’s UL listed.

The CE-12-AS water heater also holds up well in high-pressure applications for leak-free performance. It’s certified to 300 psi with a maximum working pressure of 150 psi.

You get an impressive warranty, too. There’s a choice of a 6-year warranty for residential use or a 3-year tank warranty for commercial use.


✅ Space-saving design for mobile homes and small households

✅ Non-CFC Foam Insulation

✅ Heavy-gauge corrosion-resistant steel tank

✅ Offers high thermal efficiency with more energy savings

✅ High-quality brass relief valve

✅ Easy installation and maintenance


✖️ Some components have slightly shorter warranties

✖️ A few packaging concerns

4. Westinghouse WEC080C2X045 80-Gallon 4500-Watt Electric Water Heater

Do you want a higher output with the least amount of maintenance? Say hello to Westinghouse WEC080C2X045 electric water heater.

Westinghouse’s motto has always been to ensure remarkable durability. And tell you what, this electric heater lives up to the hype.

Westinghouse WEC080C2X045 80-Gallon 4500-Watt Electric Water Heater Img

First, it has a laser-welded 316L stainless steel tank that’s remarkably sturdy and durable. It’s more durable than traditional water heaters and offers more corrosion resistance without anode rods.

Also, unlike most water heater tanks, it doesn’t have a glass lining. Hence, it offers significant weight savings, weighing only 151 pounds. For comparison, most models in this class weigh over 200 pounds.

It’s for this reason that Westinghouse offers a lifetime warranty, knowing well it will provide years of enjoyment and value.

Given the 23.25-inch diameter and 69-inch height, this electric water heater isn’t that compact. However, the 80-gallon capacity is a good tradeoff that can cater to five people or more. Such capacity makes it a cost-effective solution for commercial or residential use.

But even with such a large capacity, the Westinghouse water heater still offers 98% thermal efficiency. In fact, it only allows 0.57 degrees Fahrenheit heat loss per hour.

Westinghouse WEC080C2X045 electric heater heats up to 170 degrees Fahrenheit. Also, it has a maximum and minimum delivered temperature of 150 and 110 degrees Fahrenheit, respectively.


✅ Sleek, ultra-modern design

✅ A low standby heat loss

✅ Lightweight-in-class construction

✅ Superior corrosion resistance

✅ Lifetime warranty


✖️ Minor durability issues with the heat exchanger

5. Rheem MR50245 Marathon Tall Electric Water Heater

Can a water heater last for as long as you own a home?

That might seem a big statement for most models out there. However, for Marathon water heaters, that’s the norm.

Rheem MR50245 Marathon Tall Electric Water Heater Img

Say hello to Rheem MR50245 Marathon electric water heater, one of the most durable water heaters ever made.

It’s easy to mistake it for stainless steel models, but no. Instead, Rheem MR50245 Marathon is a non-metallic water heater but with a lifespan of over 40 years.

Yes, that’s right. This electric heater comes in the toughest molded plastic materials that resist salt, scratches, and dents.

It has a polyethylene shell and polybutene tank. In addition, it has fiberglass reinforcement for unmatched strength.

But this 50-gallon water heater isn’t all about durability.

It also has 90-94% energy efficiency. Well, it isn’t the best energy-efficiency rating. Still, it’s higher than most models. In fact, the yearly operating cost is $28 less than similar models.

The best part? It has the lowest standby heat loss, thanks to the polyurethane insulation. At just 0.5 degrees, it’s par with leading indirect water heaters.

Rheem also designs this electric water heater to provide easy maintenance. This is because of the full-flow, recessed drain valve that makes it easier to clear sediments completely.

Did you know that this electric water heater also has dry firing protection? Well, this ingenious feature prevents the heater from running without water.

Rheem offers a lifetime warranty for the tank. In addition to that is a 6-year parts warranty.


✅ Light and compact enough to set up

✅ Negligible standby heat loss

✅ High energy efficiency rating

✅ Dry-firing protection

✅ Superior corrosion resistance

✅ Strong fiberglass reinforcement


✖️ Quite expensive

6. General Electric GEH80DFEJSR 80-Gallon Hybrid Water Heater

Do you want the most energy-efficient water heater? Look no further than the GeoSpring hybrid water heater.

But what makes it the most energy-efficient water heating system on the market?

General Electric GEH80DFEJSR 80-Gallon Hybrid Water Heater Img

Well, it uses advanced heat pump technology alongside traditional electric elements. For this reason, it offers significant energy savings.

For instance, the best electric water heaters have an average energy factor of 95%. But for the GeoSpring hybrid water heater, you get an energy factor of 290%. Hence, it’s three times better than your standard electric water heater.

Also, by extracting free heat from ambient air, this hybrid water heater can help dehumidify damp spaces.

In addition, it has a programmable “vacation mode.” Hence, it helps save energy while you’re away and ensures that you have enough hot water on your return.

The best part? General Electric offers a 10-year warranty for this hybrid water heater.

Because of the heat pump, this unit is a bit loud. Plus, it requires considerable space around it. But all-in-all, the cost savings are worth it in the end.


✅ Energy Star certified

✅ 2.9 energy factor

✅ Can double as a dehumidifier for damp spaces

✅ Vacation setting


✖️ A bit loud

✖️ Requires more open space

7. HTP SuperStor Ultra 45 Gallon Water Tank

Are you still wondering about the most energy-efficient way to store water? Don’t hurt your head anymore. The SuperStor Ultra stainless steel tank is the answer.

But what makes it so special?

Foremost, the SuperStor Ultra water tank has been a market leader for over 25 years. That’s more than enough reason to trust its products.

HTP SuperStor Ultra 45 Gallon Water Tank Img

Also, this tank has a low standby heat loss, thanks to the environmentally safe, CFC-free 2-inch thick foam insulation. With this insulation, the tank loses less than 0.5 degrees per hour.

In addition, this hot water storage tank has a high output heat exchanger. In fact, it offers a higher BTU output per foot than other heat exchangers on the market.

What’s more, this tank has a durable construction.

It uses 316L stainless steel for superior temperature and corrosion resistance. So, no need for anode rods. Also, the stainless steel exterior offers an attractive, dent-free finish.

Well, this hot water storage tank has a 45-gallon capacity. However, it’s available in other sizes for residential and commercial applications.

Moreover, HTP shows confidence in its product by offering a 10-year warranty.


✅ A low standby heat loss

✅ Thick CFC-free insulation

✅ Higher BTU heat exchanger

✅ Available in different gallon sizes

✅ Superior temperature and corrosion resistance


✖️ Shallow threads on stainless steel ports

8. A.O. Smith SUN-80 Residential Solar Water Heater

Do you want a smart system that will reduce your grid-energy consumption? A.O. Smith has the answer, the SUN-80 Residential Solar Water Heater.

The problem with most solar heaters is that they heat only in the daytime. But that’s not a problem with the SUN-80 water heater.

A.O. Smith SUN-80 Residential Solar Water Heater Img

It doesn’t rely solely on solar panels, which you have to purchase separately. Instead, it has a supplementary 4500 watts electric heating element to maintain the temperature when solar energy isn’t available.

Also, you’ll appreciate that it has 2-inch thick CFC-free foam insulation that meets standby heat loss requirements. In addition, this solar water heater meets Federal Energy Efficiency Standards.

The 80-gallon steel tank, too, is designed for superior corrosion resistance. It achieves this through PermaGlas lining and CoreGuard anode rods. What’s more, it has a DynaClean diffuser dip tube to reduce sediment and scale buildup.

Moreover, this water heater has top and side connections. Such multiple connections offers= much-needed flexibility for both closed and open-loop setups.

Plus, this unit is pre-wired for mounting surface temperature sensors. However, you’ll have to purchase the sensor separately.

A.O. Smith offers a 6-year warranty on this solar water heater. Furthermore, you also get it in a 120-gallon size.


✅ Multiple connection options

✅ Meets energy standards

✅ Supplementary electric heating element

✅ Thick CFC-free foam insulation

✅ Superior corrosion resistance

✅ Mounting surface for temperature sensors


✖️ Doesn’t include solar panel

✖️ A bit hefty in size

9. Amtrol BoilerMate WH-41Z Indirect-Fired Hot Water Heater

May you want something more efficient than your typical electric or gas water heater? If so, I give you the Amtrol BoilerMate WH-41Z.

It’s quite unlike any other water heating system you might have experienced before.

Amtrol BoilerMate WH-41Z Indirect-Fired Hot Water Heater Img

First, it provides hot water by using boiler energy as the source. Hence, it minimizes fuel use while maximizing hot water output.

Also, the placement of the heat exchanger is different. Instead of having it on the sidewall like other water heaters, BoilerMate WH-41Z has a top-mounted heat exchanger.

Such a design provides more efficient heat transfer. Moreover, it’s removable and allows you to get hot water faster.

Also, this unit has mechanical temperature control instead of digital temperature control like in other water heaters. As a result, it’s more fast-acting and offers better temperature and pressure control.

This water heater achieves energy efficiency using molded insulation. It seals the gaps entirely, hence minimizing heat loss.

The shell comes in stronger deep-drawn steel. The base, too, is of heavy-gauge steel for tip-free performance.

What’s more, this water heater promises corrosion-free performance. This is because it uses a more corrosion-resistant HDPE tank that eliminates scale buildup.

BoilerMate WH-41Z has top connections to maintain a compact footprint. It’s available in 41 and 80-gallon sizes, each with 6-year warranty coverage.


✅ Uses the energy of an existing boiler system

✅ More efficient top-mount heat exchanger

✅ Fast-acting mechanical control

✅ Excellent corrosion resistance

✅ Stable steel base


✖️ Might leak if not installed correctly

10. A.O. Smith ENS-50 ProMax Electric Water Heater

The Pro-series is the latest addition to Smith’s water heater lineup.

And if you’re looking for a 50gallon electric water heater, then the ENS-50 ProMax is your best choice. This commercial-grade residential water heater offers cutting-edge features and enough capacity for a family of five.

A.O. Smith ENS-50 ProMax Electric Water Heater Img

This water heater has one of the best anti-corrosive technologies.

Foremost, it uses patented blue diamond glass coating that offers superior corrosion resistance than the industry-standard glass lining.

Also, instead of standard anode rods, this water heater uses stainless steel rods. For this reason, it provides superior corrosion resistance and extends the tank’s life more than standard anode rods.

The cutting-edge features don’t end there.

You’ll also appreciate that it has a longer-lasting stainless steel element instead of a copper element. In addition to that, it has a DynaClean diffuser tube that minimizes sediment and limescale buildup for maximum hot water output.

The ENS-50 uses high-efficiency CFC-free foam insulation to ensure low standby heat loss. This technology contributes to a 0.92 uniform energy factor, which reduces operating costs.

Just for the record, this water heater has a short form factor for space-saving installation. In addition, it includes a 6-year warranty for the tank and parts.


✅ Excellent anti-corrosion technologies

✅ Space-saving short form factor

✅ Tamper-resistant drain valve

✅ Energy-efficient design

✅ Meets NAECA standards


✅ Tends to leak if poorly installed

How to Choose The Best Indirect Water Heater

Type of Indirect Water Heater

Tank vs. tankless indirect water heaters, which one is right for you?

If you have adequate space and a large household, then a water heater with an integrated tank is better.

On the other hand, a tankless water heater will suffice if you have a small household and need an “on-demand system” that doesn’t require too much space.

But whichever water heater you choose, ensure it works with the existing energy source in your house. Some will plug into electrical outlets; others will only work with gas-fired boilers.


Consider the gallon size of the water heater.

But the question is, how much do you need?

Well, the right gallon size depends on the average daily hot water consumption and the number of people in the household. The more the number of people, the more gallons you’ll need.

Also, I recommend a slightly higher capacity than the actual average daily consumption to cater to emergencies. For instance, if your average daily consumption is 35 gallons, then a 40-gallon water heater is the best option.

Often, the best way to figure this out is to add 10 gallons per additional person. Please, refer to the table below.

Family Size Water Heater Capacity
1-2 23-36
2-3 36-46
3-4 46-56
4-5 56-80


NB: The calculation doesn’t take into account peak hour demand. Hence, the table only provides a loose estimate.

Physical Size

Indirect water heaters are relatively small. Still, ensure that the dimensions fit the available space in your home. That’s not all; it should also have an allowance for connecting to your boiler.

So, ensure to measure the available floor area and vertical clearance to get an idea of the ideal water heater size.


Once you turn off the power source, the water will start getting cold. Hence, ensure the water heater has excellent insulation to retain the heat. Most water heater tanks have thick foam insulation to ensure low standby heat loss.

Efficiency Rating

A heater’s efficiency rating indicates how much energy it uses to produce hot water. The higher the rating, the less it costs to run it.

Often, we recommend an energy factor of at least 0.93 or 93%. It will help you achieve up to 10% more savings than a standard-efficiency water heater.

Customer Reviews

Yes, you heard that right. Customers often share their experiences regarding a particular product. In fact, it’s one of the best ways to get an insight into how a particular product works in real life.

Hence, take time to read indirect fired water heater reviews from qualified buyers. You’ll learn a few pros and cons of the product, which will help you choose wisely.

Indirect Water Heater FAQs

What is an indirect water heater? How does it work?

An indirect water heater is the most energy-saving water heating system available.

It uses the existing energy from the boiler or furnace to heat water that’s circulated through the heat exchanger in the storage tank.

Is an indirect water heater worth it? What are the advantages?

Indirect water heaters use less energy than other types of water heaters. They’re also the most eco-friendly option.

Another advantage is that they provide instant hot water whenever you need it, and their design makes them easier to maintain. Also, they take up less space and don’t require venting.

Overall, an indirect heater provides a lot of benefits when compared with other types of water heaters on the market today.

What is the first-hour rating?

It’s the maximum number of gallons a water heater delivers within an hour of usage.

To get the first-hour rating of your water heater, multiply the tank capacity by 70% and add the recovery rate.

How long do indirect water heaters last?

Indirect water heaters typically last 15 to 20 years. However, some brands will last 25 years or more.


With such resources at your disposal, you’ll be able to make an informed decision on the best indirect water heater for your home’s unique needs and lifestyle!

To find an indirect water heater that will work best for your home, you must know what size you need and how much hot water you use each day. Once you have this information, it’s a simple matter of finding a suitable model with the right features to match your needs.

Now that you know what an indirect water heater is and why they’re a good option for your home, it’s time to start shopping!

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