Best Condensing Water Heaters of 2020

Categories Water Heating
Want to save energy and money on a water heater? We’ve got you covered.

Looking for an even more energy-efficient way to heat up the water in your home? Tired of the same old options? Condensing water heaters may be just the answer.

By saving lost energy while heating water appliances, they reduce your environmental impact. What more could you ask for, with our current state of earthly affairs?

So, if you want to know more about how condensing water heaters work, why they’re so beneficial, and more, read on. We even let you in on our top four condensing water heaters.

Our Top Picks

Real Talk: Sensible Digs earns a commission through the following independently chosen links at no additional cost to you.

What Are Condensing Water Heaters?

The average water heater is useful for heating the water appliances in your home. These include your morning shower, your dishwasher, and the like. But what makes a condensing water heater different from the usual water heaters?

When water heats up, it produces water vapor. This is the steam you may recognize from processes like boiling your kettle (1). When this occurs, latent heat of vaporization — which is the energy used to convert a liquid into gas — is lost.

However, in a condensing water heater, the latent heat of vaporization is recovered. This ensures that energy isn’t wasted, but is utilized within the water heater.

In fact, condensing water heaters retain around 90 percent of the energy that may otherwise be lost in the process. This makes for an efficient means of heating the water in your home.

Condensing water heaters are fuelled using either gas or oil. However, our top four, which you’ll find below, all use gas.

Types of Condensing Water Heaters

Before we go any further, we think it’s important that you know exactly what you’re getting yourself in for. This way, you can make the most informed decision. So, we’re going to let you in on the different types of condensing water heaters:

Tank vs. Tankless

Heaters with tanks are often found within the home, storing water ready for use. They’ll usually be hidden in a cupboard somewhere, away from the rest of the home.

Alternatively, tankless options require a little less space than tanks. These heat up water instantly within their mechanism.


A.O. Smith GPVL-50 ProMax Power Vent Gas Water Heater, 50 gal
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It’s in the name really — a tank heater will store warm water, ready for use. They’re usually pretty cheap, easy to install, and will be found in most older houses.

However, these days, people are transferring to the tankless option. They’re a little more practical, particularly for larger families due to the limitless hot water they provide.

None of our options below come with a tank — tankless all the way. Heaters with tanks are becoming pretty obsolete these days. It’s no wonder we couldn’t find any to recommend, even after scouring the internet.

  • Cheaper
  • A finite amount of water.
  • Must keep water within them hot at all times, wasting energy.


Takagi T-H3-DV-N Condensing High Efficiency Natural Gas Indoor Tankless Water Heater, 10-Gallon Per Minute, 199,000 BTU
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Tankless water heaters take cold water from the water source of your home. They then heat this water instantly in the boiler and expel it through your taps or shower heads. This results in a continuous supply of hot water — particularly ideal for larger families.

Although they’re a little more expensive to install, they save a lot of energy. This is because they don’t have to maintain the heat of the water in the tank. So, despite the initial hefty cost, over time, they’ll certainly make up this money through energy-saving (2).

  • Instant water heating.
  • Unlimited water heating.
  • Take up less space than a tank heater.
  • Energy-saving.
  • More expensive than a tank heater.

Learn More
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Digital vs. Remote

Some of our options for the best condensing water heaters will be operated via the tank itself. In other cases, the product can be operated using a thermostat. But what’s the difference?


Takagi T-H3-DV-N Condensing High Efficiency Natural Gas Indoor Tankless Water Heater, 10-Gallon Per Minute, 199,000 BTU
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Digital water heaters have an operating system on the machine. This requires you to actually go to the heater itself to sort out the settings.

  • Easy to use.
  • Not ideal to access if your heater is in a remote location or you have poor mobility.


Noritz NRC66DVNG Indoor Condensing Direct Tankless Hot Water Heater, 6.6 GPM - Natural Gas
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These units have no buttons on the boiler itself. Instead, they are operated using a thermostat which you can mount in any room of the house.

An ideal location is in, or near, the kitchen. This makes it super easy to access, as it’s usually the most used room in the house.

  • Requires minimal effort to turn the water heater up or down.
  • May require a little more installation than a digital water heater.

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Choosing the Best Condensing Water Heater

Here are a couple of factors we think you should keep in mind before you make your purchase.

1. Tank or Tankless

We’ve shown you the difference between tank condensing water heaters and tankless ones. Therefore, it’s probably no surprise that we think the tankless options are best.

Smaller and more compact than tank options, they also help you to save energy — more than the average water heater.

This is why, in our list below, we’ve only provided tankless options.

2. Low NOx Emissions

This is a pretty common trait in condensing water heaters, and it’s a great trait at that. Nitrogen Oxide is a common waste matter from gas-operated machines. It is a poisonous gas known to contribute to the thinning of the ozone layer (3).

With current environmental concerns, it’s important to do everything we can to avoid exacerbating this problem. This is why we prefer low NOx emitting water heaters.

3. Small and Compact

Although this factor may not be as significant here as it is for portable water heaters, it’s still important. Most of us like to make sure everything has its rightful place in the home, and the water heater is no exception.

As such, we’ve chosen four small options that will be barely noticeable amongst your home decor.

4. High Flow Rate

The flow rate — number of hot water sources that can be used at one time — is measured in gallons per minute, or GPM. The higher the GPM, the more showers can be taken at one time. This alongside the dishwasher, washing machine, faucets, and the like!

In general, one sink uses around 1.5 GPM, and one shower uses around 2.1. So, every one of our options below is a winner in our eyes, as they all exceed 6.5 GPM. The larger your family, the higher a GPM we would recommend, so take your pick.

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The Best Condensing Water Heaters of 2020

After researching every corner of the internet, we’ve found what we believe are the four best condensing water heaters currently available on the market.

We’ve found a safe option, a good-looking one, an option for an exceedingly high flow rate, and a really small one! Whatever your idea of what “the best” constitutes, we’ve got you covered.

1. Takagi T-H3-DV-N Condensing Tankless Water Heater

Highest Flow Rate

Takagi T-H3-DV-N Condensing High Efficiency Natural Gas Indoor Tankless Water Heater, 10-Gallon Per Minute, 199,000 BTU
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With its digital interface, the Takagi condensing water heater is super to easy-to-use. Simply connect it to your gas mains pipe, and it’ll provide hot water for up to four showers in one go!

Takagi pride themselves on their ability to tailor their water heaters to your needs. This is why they produce a variety of units, in different sizes and flow rates, to suit your requirements.

  • High GPM.
  • Emits low amounts of NOx.
  • Digital.
  • Provides less hot water at a time in colder climates.

Why We Love It

High GPM

One of the best features of this water heater is its high flow rate. You can have more water appliances operating at one time than any other option on our list, without the risk of the water going cold.

This makes the Takagi water heater ideal for a larger family. Perhaps this would also make a great option for a student house, as they usually have a lot more showers than the average home.

10 GPM equates to nearly five showers at one time! That’s pretty impressive. It ensures every water appliance in your house — showers, sinks, dishwashers, and the like — can be used all at once.

Emits Low Amounts of NOx

Anything with low NOx emissions is a bonus for us. This way, you’ll be reducing your carbon footprint — something everyone should get on board with in today’s world.


Digital interfaces are becoming a lot more common for household goods. Everything from coffee machines to blenders is now digital. Water heaters are no different.

The Takagi water heater has a digital interface, for ease-of-use. Even a novice can work one of these — no need for a technology whizz in the household.

Keep In Mind

Provides Less Hot Water in Colder Climates

In colder temperatures, the incoming groundwater temperature will naturally be cooler. The water entering into a tankless water heater will therefore be cooler. This allows for fewer warm water appliances to operate at one time.

So, before purchasing one of these Takagi water heaters, be sure the product suits your water needs. If you have a larger family needing multiple showers per day all year round, this is something to consider.

Additional Specs

Dimensions 11.2 x 17.8 x 24.9 inches
Weight 85 pounds
Flow Rate (Gallons Per Minute) 10 GPM
Input Type Gas operated
Digital or Remote? Digital
Indoor or Outdoor Use? Indoor only

2. Noritz NRC66DVNG Indoor Condensing Tankless Water Heater

Smallest Condensing Water Heater

Noritz NRC66DVNG Indoor Condensing Direct Tankless Hot Water Heater, 6.6 GPM - Natural Gas
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The Noritz condensing water heater is another tankless option. It also provides an energy-saving mechanism, with low NOx emissions. Want endless water for the whole family? You got it.

This product is ideal for anyone with limited space in their home. No need for the capacity of a usual tank boiler, as it can fit discreetly almost anywhere.

With its simple white design and small footprint, we really like how it looks.

  • Long warranty.
  • Remote control.
  • Small and lightweight.
  • Disappointing flow rate.

Why We Love It

Small and Lightweight

This is another pretty small option, actually achieving the accolade for the smallest of our picks. You can stow this option away in any small area in the house, like a cupboard or smaller room. It’s pretty non-obtrusive and ideal for anyone concerned over aesthetics.

Remote Control

Most people will stow their water heater away in a location where it can’t be seen. If this is the case, a great way of managing it is through a remote interface.

Pair this unit with that technology, and you can control it from a wireless thermostat in any chosen room.

Long Warranty

What we particularly love about the Noritz water heater is the long warranty. It includes a 12-year warranty on the heat exchanger, five on parts, and one on labor. So, you’ll be covered for almost all eventualities, showing that the company takes pride and has faith in its product.

Keep In Mind

Disappointing Flow Rate

Despite promises that this heater has the highest flow rates on the market, this is not the case. It falls short, especially when compared to the other water heaters on our list. That said, it’s still a pretty high flow rate of 6.5 to 6.6 GPM, considering its tankless nature.

Additional Specs

Dimensions 6.7 x 13.8 x 23.6 inches
Weight 39 pounds
Flow Rate (Gallons Per Minute) 6.5 GPM
Input Type Gas operated
Digital or Remote? Remote
Indoor or Outdoor Use? Indoor

3. Rinnai RUR98iN Ultra Series Tankless Water Heater

Most Aesthetically Pleasing

Rinnai RUR98iN Ultra Series Condensing Indoor Natural Gas Tankless Water Heater, 9.8 Max
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The Rinnai water heater is another condensing water heater with a pretty extensive warranty. This shows us that the product is made to do the job and we can trust the company.

It also has a super sleek metal exterior. Although a little larger than some other options, this one should fit in nicely in any home. Once installed, simply tell it what to do using the remote interface — it’s as easy as that.

  • Extensive warranty.
  • Remote use.
  • Sleek and aesthetically pleasing.
  • Heavy.

Why We Love It

Sleek and Aesthetically Pleasing

If you’re looking for a good-looking, sleek condensing water heater, then this one’s for you. It’s easy-to-use, relatively small, tankless, and has a high GPM. It’s not only pretty but practical too.

It’ll do the job you want it to while fitting seamlessly into your home decor.

Remote Use

We love a product that can also connect with a remote interface. Most people will mount the remote interface somewhere communal, like the kitchen or living area.

This way, there’s no need to run to the basement, or wherever your water heater is stowed, to change the temperature of your home. Instead, you can simply access your water heater from a more communal area — much less effort.

Extensive Warranty

We admire a product with a long warranty. Why? Well, it shows that the company has faith in its product.

Simply take a look at the long list of warranty extras to see how proud Rinnai is of this water heater. They include a limited 12-year warranty on the heat exchanger, five on parts, and one on labor. You can’t go wrong with that.

Keep In Mind


Despite the easy use, this unit is pretty heavy. So it may be a little more difficult to maneuver into your property than our others. That said, once it’s in, it’s in, so it shouldn’t cause you many issues after installation.

Additional Specs

Dimensions 12.5 x 10 x 26 inches
Weight 81.6 pounds
Flow Rate (Gallons Per Minute) 9.8 GPM
Input Type Gas operated
Digital or Remote? Remote
Indoor or Outdoor Use? Indoor only

4. Rheem RTGH-84DVLP Indoor Condensing Tankless Water Heater

Best for Safety

Rheem RTGH-84DVLP Indoor Direct Vent Liquid Propane Condensing Tankless Water Heater Low Nox
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If you’re looking for a safe option, this one may be the choice for you. That’s not to say that all our other options aren’t safe, it just means that this one is ultra safeguarded.

This makes it ideal for a large family, with smaller kids, who want that extra peace of mind.

  • Includes overheat technology.
  • Freeze protection.
  • Remote.
  • Low NOx burner.
  • Not the smallest, or the best looking.

Why We Love It

Includes Overheat Technology

What makes this option stand out above our other best condensing water heaters is the overheat film wrap. This means that, no matter how hard the water heater is working, it should remain safe within your home.

Freeze Protection

The product safeguards against much colder temperatures. This ensures there’s little worry of the product breaking during extreme temperature conditions.


This is another remote option, controllable from a communal room, like the kitchen. It really is convenient when you don’t have to travel all the way to the water heater to set it up.

Keep In Mind

Not the Smallest, or the Best Looking

If you’re looking for a small, aesthetically pleasing option, which blends into your home sleekly and appealingly, this one’s not your guy. In fact, the plastic exterior makes it look pretty dated.

That said, looks aren’t everything, and if you’re willing to sacrifice aesthetics for safety, the Rheem condensing water heater will suit you well.

Additional Specs

Dimensions 9.8 x 18.5 x 27.5 inches
Weight 76.9 pounds
Flow Rate (Gallons Per Minute) 8.4 GPM
Input Type Gas operated
Digital or Remote? Remote
Indoor or Outdoor Use? Indoor

Detailed Comparison

Product Award Dimensions Weight Flow Rate (GPM) Input Type Digital/ Remote Indoor/ Outdoor
Takagi T-H3-DV-N Highest Flow Rate 11.2″ x 17.8″ x 24.9″ 85 lbs 10 Gas Digital Indoor
Noritz NRC66DVNG Smallest Heater 6.7″ x 13.8″ x 23.6″ 39 lbs 6.5 Gas Remote Indoor
Rinnai RUR98iN Most Aesthetically Pleasing 12.5″ x 10″ x 26″ 81.6 lbs 9.8 Gas Remote Indoor
Rheem RTGH-84DVLP Best For Safety 9.8″ x 18.5″ x 27.5″ 76.9 lbs 8.4 Gas Remote Indoor
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And That’s a Wrap

In this article, we’ve simplified the seemingly complicated mechanism of choosing the best condensing water heater so you can decide if one is for you. We’ve also provided you with our four favorites on the market.

We hope you’ve enjoyed learning about them, and what to look for when purchasing one. If you have anything more to add, please feel free to comment below. We’d love to hear your thoughts!

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About the Author

Peter Gray

Peter has been a homeowner for 35+ years and has always done his own repair and improvement tasks. As a retired plumber, Peter now spends his time teaching others how they can fix leaks, replace faucets, and make home improvements on a budget.
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