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Best Condensing Water Heaters of 2023

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

If you’re looking for an energy-efficient way to heat the water in your home, a condensing water heater could be the answer. However, choosing which one to buy can be difficult.

After researching in every corner of the internet, we found what we believe are the 4 best condensing water heaters currently available.

To help you choose, we have highlighted heaters that are particularly safe, visually appealing, feature an exceedingly high flow rate, and one that is very small!

Our Top Picks

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Product Comparison Table

Product Image of the Takagi T-H3-DV-N Condensing High Efficiency Natural Gas Indoor Tankless Water Heater, 10-Gallon Per Minute, 199,000 BTU
Highest Flow Rate
Takagi T-H3-DV-N
  • High flow rate at 10 GPM
  • Emits low amounts of NOx
  • User-friendly digital interface
Product Image of the Noritz NRC66DVNG Indoor Condensing Direct Tankless Hot Water Heater, 6.6 GPM - Natural Gas
Smallest Condensing Heater
Noritz NRC66DVNG
  • Weighs just 39 lbs
  • Remote controlled thermostat
  • 12-year warranty
Product Image of the Rinnai RUR98iN Ultra Series Condensing Indoor Natural Gas Tankless Water Heater, 9.8 Max
Most Aesthetically Pleasing
Rinnai RUR98iN
  • Sleek metallic exterior.
  • Remote interface
  • 12-year warranty
Product Image of the EZ Ultra HE Natural Gas Indoor Condensing Tankless Water Heater - Digital Display - Whole Home
Most Efficient
EZ Ultra HE
  • Can be installed horizontally or vertically
  • Fully automatic
  • Works with low water pressure (8 psi)

Product Reviews

Here are 4 condensing water heater reviews for you to consider.

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

Highest Flow Rate

With a digital interface, the Takagi condensing water heater is very easy to use. Simply connect it to your mains gas pipe and it will provide enough hot water for up to four showers at once!

Takagi pride themselves on their ability to tailor their water heaters to your needs. That is why they produce various units in different sizes and flow rates to meet your requirements.

What We Like

High GPM

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

This makes the Takagi water heater ideal for a larger family. It is also a great option for a student house, as they usually have more showers than the average home.

10 GPM equates to nearly five showers at once! That’s pretty impressive. It ensures every hot water appliance in your house can be used at the same time.

Emits Low Amounts of NOx

Anything with low NOx emissions is a positive for us. You will be reducing your carbon footprint, something everyone should get on board with.

Digital Interface

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

The Takagi water heater features a digital interface for ease of use. Even a novice can operate one of these, so there’s no need for a technology whizz in the house.

What We Don't Like

Provides Less Hot Water in Cold Climates

In colder temperatures, the water supply will naturally be cooler. As colder water enters the tankless water heater, it will be able to produce less hot water, meaning fewer warm water appliances can operate at once.

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

Product 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

The Noritz condensing water heater is another tankless option. It also features an energy-saving mechanism with low NOx emissions. If you want endless warm water for the whole family, you’ve found it.

This option is ideal for anyone with limited space in their home. Unlike a traditional tank heater, it can fit discreetly almost anywhere in your house.

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

What We Like

Small and Lightweight

This is another relatively small option, earning the accolade for the smallest of our picks. You can hide this heater away in any tight part of the house, such as a cupboard or smaller room. It’s non-obtrusive and ideal for anyone concerned about aesthetics.

Remote Control

Most people will want their water heater somewhere it can’t be seen. If this is the case, it is still easy to manage it via a remote interface.

By using a remote control, you can operate the heater from a wireless thermostat in any room you choose.

Long Warranty

One of our favorite features of the Noritz water heater is its long warranty. It includes a 12-year warranty on the heat exchanger, five on parts, and one on labor. This means you will be covered for almost any eventuality, showing that the company takes pride and has faith in its product.

What We Don't Like

Disappointing Flow Rate

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

Product 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

The Rinnai water heater is another condensing water heater with a pretty extensive warranty. This tells us that the product is made to do its job and that we can trust the company.

It also has a super sleek metal exterior. Although it is a little larger than some other options, it should still fit nicely into any home. Once installed, you can easily tell it what to do using the remote interface.

What We Like

Sleek and Aesthetically Pleasing

If you’re looking for an attractive, sleek condensing water heater, this one is for you. It’s easy-to-use, relatively small, tankless, and has a high GPM.

It’s not only pretty but also practical. It will do what you ask of it while fitting seamlessly into your home.

Remote Use

We admire a product that can be operated with a remote interface. Most people will mount the remote interface somewhere communal, such as the kitchen or living area.

This means there’s no need to run to the basement or wherever your water heater is hidden to adjust the temperature of your home. Instead, you can access your water heater from a more communal area, which is far more convenient.

Extensive Warranty

We appreciate a product with a long warranty. It is usually a good sign that the company has faith in its product.

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, which is great for your peace of mind.

What We Don't Like


Despite the ease of use, this unit is pretty heavy. It could be a little more difficult to maneuver into your property than the others on our list. That said, once it’s in, it’s in, so its weight shouldn’t cause you extra issues after installation.

Product 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. EZ Ultra HE Condensing Tankless Water Heater

Most Efficient Condensing Water Heater

If high efficiency is your priority, check out this water heater from EZ. It uses advanced condensing technology which utilizes exhaust gas. This preheats incoming water to provide maximum efficiency.

This heater eliminates much of your home’s stand-by energy to reduce loss. In turn, this saves you both energy and money.

It also has high thermal efficiency and excellent combustion performance. Overall, you’re getting more for your money with this purchase.

What We Like

Versatile Installation

You can install for horizontal or vertical venting. This might seem like a minor detail but it can help you save space as you can fit it into your home’s specific design.

Fully Automatic

To use it, simply turn on the faucet or shower and it will activate automatically. It even has fully automatic temperature modulation. Once you choose your temperature, the unit will regulate itself to maintain this. When you turn the tap off, the water heater will automatically stop.

Works With Low Water Pressure

Even if you have low water pressure, this heater can still work. It can function on as little as eight PSI. This is a good choice for people living at high altitudes as well as those using older pumping systems that might not be as powerful.

What We Don't Like

Not for Large Homes

This water heater is designed for homes with a maximum of two bathrooms. If you have more than that, this isn’t going to be suitable.

Not Good for Quick Hand Washing

Because it takes a few moments to heat the water, it isn’t suitable for 20-second hand washes. You might find that using cold water is more efficient.

Product Specs

Dimensions 27 x 14.5 x 6.5 inches
Weight 31 pounds
Flow Rate (Gallons Per Minute) 3.4 GPM
Input Type Gas operated
Digital or Remote? Digital
Indoor or Outdoor Use? Indoor

Product Comparison Chart

Product Award Dimensions Weight Flow Rate 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 GPM Gas Digital Indoor
Noritz NRC66DVNG Smallest Heater 6.7″ x 13.8″ x 23.6″ 39 lbs 6.5 GPM Gas Remote Indoor
Rinnai RUR98iN Most Aesthetically Pleasing 12.5″ x 10″ x 26″ 81.6 lbs 9.8 GPM Gas Remote Indoor
EZ Ultra HE Most Efficient 27″ x 14.5″ x 6.5″ 31 lbs 3.4 GPM Gas Digital Indoor

How do Condensing Water Heaters Work?

When water heats up, it produces vapor. When this occurs, the latent energy used to convert a liquid into a gas is lost. However, in a condensing water heater, the heat of vaporization is recovered. This ensures the energy isn’t wasted but is utilized within the water heater.

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

Condensing water heaters are fuelled using either gas or oil. However, the four heaters featured on our list all use natural gas.

Things to Consider

There are a couple of factors you should keep in mind before you make your purchase.

Tank or Tankless

Heaters with tanks are often found in homes and store hot water ready for use. They are usually hidden in a cupboard or loft, away from the rest of the home.

Tankless units require less space than those with tanks. They heat up the water almost instantly within their mechanism.


As suggested by the name, a tank heater stores warm water, ready for use. They’re usually relatively cheap, easy to install, and can be found in most older houses.

Today, people are increasingly switching to tankless options. They are often more practical, particularly for larger families, as they can provide hot water indefinitely.

None of the units in our list require a tank. Heaters with tanks are becoming obsolete, so it’s no wonder we couldn’t find any to recommend, even after scouring the internet.


  • Cheaper


  • A finite amount of water.
  • Keeping water hot requires the heater to be active, wasting energy.


Tankless water heaters take cold water from a water source. They then heat the water rapidly in their boiler and expel it through taps or showerheads. This results in a continuous stream of hot water, ideal for larger families.

Although they are more expensive, they save a lot of energy because they don’t need to maintain the water temperature constantly. This means that despite the initial cost, in time they will pay for themselves with reduced energy bills (1).


  • Near-instant and indefinite water heating.
  • Occupies less space than a tank heater.
  • Energy-saving.


  • More expensive than a tank heater.
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Digital or Remote

Some condensing water heaters will be operated via the unit itself. In other cases, the product can be operated using a thermostat. What’s the difference?


Digital water heaters feature an operating system on the machine. These require you to physically go to the heater itself to adjust the settings.


  • Easy to use.


  • Can be difficult to access if your heater is far away or you have poor mobility.


These units have no buttons on the boiler itself. Instead, they are operated using a thermostat that you can mount in any room of the house.

The most popular location is in or near the kitchen. This makes it very easy to access, as it is often the most used room in the house.


  • Requires minimal effort to turn the water heater up or down.


  • Could require more installation work than a digital water heater.
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Low NOx Emissions

This is a common trait in condensing water heaters and one of the most positive. Nitrogen Oxide is commonly vented from gas-operated machines. It is a poisonous gas known to contribute to the thinning of the ozone layer (2).

With current environmental concerns, it’s important to do everything we can to reduce this impact. That is why we prefer low NOx emitting water heaters.

Small and Compact

This is less critical here than for portable water heaters, but it’s still important. No home has an unlimited amount of space and your condensing water heater will need a dedicated area.

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

High Flow Rate

The flow rate, the number of water outlets that can be used at once, is measured in gallons per minute or GPM. The higher the GPM, the more showers that can be taken at the same time. This is combined with the dishwasher, washing machine, faucets, and so on!

In general, one sink faucet uses around 1.5 GPM, and one shower uses around 2.1. All of the heaters listed below should cope perfectly well, as they all exceed 6.5 GPM. The larger your family, the higher a GPM we recommend, so take your pick.


What is a Condensing Water Heater?

Condensing water heaters reduce wasted energy by utilizing condensation that was traditionally vented from the system. This water is heated and reused, greatly reducing the waste by the heater. New condensing heaters are considerably more expensive than traditional units but they make up for this by reducing energy bills.

Are Condensing Water Heaters More Efficient?

Condensing water heaters are far more efficient than conventional heaters. They can come close to doubling the efficiency of traditional heaters, especially if your existing hot water system is relatively old. The downside of this is that they are also far more expensive to buy but they will pay for themselves by significantly reducing your energy bills.

Are Condensing Water Heaters Tankless?

Just as traditional heaters can be tankless or feature a tank, both types of condensing water heaters are available. Whether you want a tank or tankless heater will depend on your personal circumstances. If you have a large family and multiple bathrooms, you might be better off with a large tank. If you have one bathroom and space is at a premium, a tankless heater should be sufficient for your needs.

Are Condensing Water Heaters Worth It?

Condensing water heaters are worth it if you’re interested in a lower-cost unit that also provides increased efficiency. Your water heating efficiency will increase from 85 percent to 95 percent if you install a condensing water heater.

Additionally, your energy consumption will go down, and you will have less impact on the degradation of the environment.

Does a Condensing Tankless Water Heater Need a Drain?

Yes, condensing water heaters need a drain. This additional heat can be recycled through a tankless condensing water heater. It is considered a closed system since the vapor is not released into the atmosphere until after it has served its purpose in the heating process.

The unit’s interior serves both to cool the exhaust gases and collect the condensation water it produces during operation. The water that has been gathered as condensation needs to be neutralized before it can be drained, and this process takes place within the apparatus itself.

How Much is a Condensing Water Heater?

The cost of a condensing heater is around $2,000. The cost of the more recent versions will still be two to three times that of the ordinary ones.

How Do You Install a Condensing Water Heater?

Installing a condensing water heater can be a bit more complicated, especially since extra parts need installing (such as the drain). If you are renovating your heating system from one traditionally configured, condensing water heaters are not a straightforward solution.

You are going to need to install brand new gas lines as well as venting systems. Taking into account the hourly wages of plumbers and electricians brings the potential cost of this new configuration up to the hundreds of dollars range.

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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.