What Is A Condensing Tankless Water Heater

What is the difference between a Condensing and Non-Condensing Tankless Water Heater?

You’ve just begun your research into the possibility of purchasing a tankless water heater, and you’ve come across a few terminology that you don’t understand:

  • A tankless water heater that condenses
  • A tankless water heater that does not condensate

There are two types of tankless water heaters: those that condense and those that don’t.

You already know you want a condensing unit. Here’s why you should stop renting and opt for ownership.

As a consequence of the combustion of the fuel in your tankless water heater, steam or water vapour is produced. The steam or vapour cools and condenses on a surface as it cools and condenses. The condensation water is corrosive, and it will erode virtually any material found in a typical household appliance. A non-condensing tankless water heater will exhaust these hot byproducts, which will cool outside the unit as they exit the unit. This substance is extremely hot, reaching temperatures of around 150 degrees Celsius, and it must be ventilated through heat-resistant and corrosion-resistant channels.

You invest money to burn the fuel, and you should be able to extract as much energy as possible from that fuel in the form of heat in return.

Condensing units have efficiencies in the range of 80 percent.

We bet you can guess why condensing tankless water heaters are so popular, now.

Condensing tankless water heaters recycle that additional heat and only release the vapour when the heat is no longer usable for the heating process, which is approximately 38 degrees Celsius in most cases. As a result, because the vapour from a condensing tankless water heater vent is significantly colder, it does not necessitate the use of the same costly venting material. A regular PVC pipe is frequently utilized since it can readily handle the high temperatures and corrosiveness of the vapour in a safe manner.

The exhaust gases are cooled inside the unit, and the condensation water is now collected inside the unit as well as outside the unit.

It is constructed using a material that is comparable to that used in the venting channels of a non-condensing unit.

This is accomplished by the use of a filtering mechanism built inside the device.

What does this all mean?

The two types of tankless water heaters are constructed in a different manner but with identical materials, so selecting one over the other does not always result in a savings in terms of money at the time of purchase. A condensing tankless water heater, on the other hand, achieves higher fuel efficiency, which translates into considerable long-term savings. Tankless water heaters are becoming increasingly efficient, and condensing units are the most energy-efficient models currently available, according to industry experts.

Today is the day to contact your local ClimateCare member and learn more about the most energy-efficient upgrades for your hot water system.

Condensing vs Non-Condensing Tankless Water Heaters: Which is Better?

After several months of internet study and shopping, you have come to the conclusion that you should acquire a tankless water heater. The prospect of getting rid of your old, bulky fifty-gallon water heater that takes up an inordinate amount of space in the laundry room seems a little exciting. But it’s not! Consider how you may make use of all of the extra space created by removing the tank from your home. But first and foremost, you must determine whether you want to purchase a condensing or non-condensing water heating system.

Take a minute to understand the differences between them before making your decision.

1. What Is A Tankless Water Heater?

A tankless water heater, as the name suggests, does not have a tank attached to it that stores and warms the water, as do typical water heaters. Instead, cold water is heated as it passes through a heat exchanger, and it is used immediately rather than being held in a tank. The heat exchanger heats the water by utilizing combustion to do so. In the process of passing through the stainless-steel pipes and being directed towards your faucets, cold water heats up and ultimately becomes hot. Due to the fact that it is exceptionally efficient and cost-effective when compared to typical water heater tanks, this form of water heating system has become quite popular.

Tankless water heaters are available in two varieties:

  • Tankless water heaters that do not condense
  • Tankless water heaters that do condense

What’s The Difference Between Condensing And Non-condensing Tankless Water Heaters?

Because they use fuel, water heaters create steam as a consequence of their operation. The vapor or steam cools and condenses on a surface as it cools and condenses. The condensation water is corrosive, and it will erode all of the materials used in typical household appliances.


The great majority of tankless water heaters that run on natural gas are non-condensing devices. Because they can make use of a home’s existing ventilation, these systems are frequently the first type of tankless system that consumers pick when switching from a standard tank model to a tankless system. A non-condensing tankless water heater has the capability of venting the steam, which allows it to cool outside the tankless water heater. This steam must be evacuated through tubes that are both heat and corrosion resistant.

As a result, there is just one heat exchanger in the system.

When we term “hot,” we are referring to temperatures that reach up to 302 degrees Fahrenheit.


It is possible to recycle this surplus heat with a condensing tankless water heater. As a closed system, it only vents the vapor when it is no longer helpful for the heating process. It is therefore referred to as such. The vapor from a condensing tankless water heater is substantially colder than that from a traditional tank water heater. As a result, it does not necessitate the use of the same expensive and intricate venting material. A regular PVC pipe is frequently used to withstand the high temperatures and corrosiveness of steam.

They are intended to recirculate exhaust through the system before releasing it into the atmosphere.

The exhaust gases are cooled inside the unit, and the condensation water is collected inside the unit as well as the outside environment. The accumulated condensation water must first be neutralized, which is accomplished within the unit, before it can be drained away.

Which Tankless Water Heater Is More Efficient?

Condensing water heater models surpass their non-condensing counterparts in terms of efficiency by 90 percent against 80 percent, if efficiency is important. However, keep in mind that, regardless of which one you select, both are more energy efficient alternatives to electric vehicles.

Which Type Of Tankless Water Heater Is More Expensive?

Because of the additional heat exchanger, condensing tankless water heaters are often the more costly of the two options. These additional components may need additional maintenance over the course of the product’s lifecycle, which will increase the overall cost of the product. While this balances out in terms of long-term electricity savings, the initial expenditure may be too much for some people who are on a tight financial budget to bear. Non-condensing units are often the least expensive choice.

Which Tankless Water Heater Lasts Longer?

A tankless water heater fueled by natural gas has a lifespan that can easily exceed 20 years if it is properly maintained. However, it is crucial to remember that both condensing and non-condensing versions include components that will wear out more quickly than the other. If you have a condensing tankless water heater, for example, the pipes that handle the condensing must be made of a high-quality, corrosion-resistant material. These may deteriorate with time and necessitate the replacement of the item.

Over time, this might lead to degeneration and leaks in the system.

Which Tankless Water Heater Produces More Savings?

Condensing tankless water heaters save money by recycling their wastes to generate more heat, which allows them to operate at a lower cost. It is possible that this byproduct can be recycled back into your water lines, which will lower your water costs, depending on how you have linked the condensation line to your water lines (slightly).

Is One Tankless Water Heater Better For The Environment Than Another?

Each of the tankless water heaters emits only trace amounts of hazardous vapors into the environment. This is one of the disadvantages of relying on natural gas. Although condensing units have a far lower carbon footprint than any other tankless water heater now on the market, they are nevertheless significantly more expensive.

Condensing Vs. Non-Condensing Water Heaters

You were under the impression that choosing a water heater would be an easy chore, until you learned about tankless water heaters. You were suddenly confronted with a slew of condensing and non-condensing water heater options. We hope that the information provided in the following section has answered your questions and helped you to make an informed decision. Please do not hesitate to contact Nick’s PlumbingAC if you want any clarification. Tankless water heaters, both condensing and non-condensing, are our specialty.

Condensing vs. Non-Condensing Tankless Water Heaters

Tankless water heaters that condensate vs those that do not condensate Tankless water heaters are becoming increasingly popular in the United States, and there is a growing variety of models and manufacturers to choose from. So, Condensing Tankless Water Heaters are a word that has been bandied around recently; what is the meaning behind it? Tankless water heaters, as the name implies, do not have a storage tank for holding water, as do classic tank-style water heaters. In a tankless water heater, the water is heated as it passes through the heat exchanger, which is heated by combustion at a higher temperature than a traditional water heater.

  • Steam, or to be more precise, water vapor, is one of these hot gases.
  • The acidity of the condensation water (pH 3-5) makes it corrosive, thus it should be avoided.
  • Using a non-condensing tankless water heater, these hot gases will be forced via its vent and out to the outside.
  • These gases have temperatures in the range of 300 degrees Fahrenheit and must be evacuated using non-corrosive venting materials that can handle the high temperatures involved.
  • A fuel was burned in the combustion process, and the energy released was utilized to heat the water, but not all of it was used to do so.
  • The higher the temperature of the exhaust gases, the less energy is required to heat the water, resulting in a lower overall efficiency.
  • Tankless Water Heaters with Condensing Technology By using a variety of methods, condensing tankless water heaters absorb the excess heat from the exhaust gases and, as a result, emit cooler gases, which are typically about 100 degrees Fahrenheit.
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Because the exhaust gases are now considerably cooler, a less expensive venting material may be utilized.

As a result of utilizing the remaining exhaust heat to heat the water, we have achieved improved efficiency, with a high 90 percent efficiency rating (up to 98 percent ).

The claimed efficiencies of the manufacturer are attained mostly in laboratory under controlled settings, and real-world values may be lower than those reported.

In the case of a tankless water heater, the heat exchanger serves as its heart.

It is necessary to neutralize the condensation water collected before it may be discharged to the exterior of the building.

Conclusively Condensing Tankless Water Heaters are extremely energy efficient (up to 98 percent), are true energy savers, and utilise a low-cost venting material to achieve their high efficiency.

They are somewhat more expensive to construct, but in comparison to non-condensing tankless water heaters, which need the use of expensive stainless steel venting materials and are less efficient, they are comparable in price and performance (about 80 percent ).

Residential Condensing Gas Tankless Water Heaters

A. O. Smith’s condensing natural gas and propane tankless water heaters are extremely energy efficient, and all of their models are ENERGY STAR ®certified. In addition to being available in both indoor and outdoor settings, tankless models from A. O. Smith are known for combining excellent efficiency with innovative designs.

More About Each

Tankless water heaters save space and provide continuous hot water for your home, but the difference between a condensing water heater and a standard tankless water heater is the ability to utilize excess heat efficiently through the use of a second heat exchanger, which increases efficiency and produces more hot water than a standard tankless water heater. The quick heating of water that occurs when water passes through the heat exchanger within the tankless unit is due to the fact that tankless water heaters do not have a tank to store their water supply.

  • Your condensing tankless unit will conserve more energy as a consequence of this process of using the extra heat rather than venting it out of the heater, resulting in a uniform energy factor (UEF) of greater than 0.90 and generating more hot water than non-condensing tankless heaters.
  • O.
  • remove circle outline A condensing tankless water heater has some advantages, but it also has some limitations.
  • The total cost of installation might vary based on the precise venting requirements of your home.
  • A tankless water heater can survive up to 20 years, depending on the quality of the incoming water, how often it is used, and how well it is maintained.
  • The appropriate size of a tankless water heater is determined by a variety of factors, including the kind of equipment you own, the number of people who live in your house, and the temperature of the incoming water.
  • Selector is a web-based tool that may also be downloaded as an app.

Condensing tankless water heaters are extremely energy efficient and have earned the ENERGY STAR ® certification.

add circle outline What factors should I bring up with my contractor before making the decision to purchase a tankless water heater?

Condensate drainage is required for condensing tankless water heaters, but not for non-condensing tankless water heating systems.


Smith tankless water heaters are designed to be frost resistant from the factory.

add circle outline Is it possible for me to install a tankless water heater on my own?

Consequently, it guards against incorrect gas line size and ventilation, which can compromise safety and performance. This is why the 15-year limited warranty is only valid if the product is installed by a certified installation company.

Benefits of Condensing Tankless Water Heaters

When installed with a recirculation pump, condensing gas tankless water heaters provide continuous, on-demand hot water for your house. When installed without a recirculation pump, they can give immediate hot water.

Space Savings

Because they may be installed in small or tight spaces both inside and outside of your house, A. O. Smith’s condensing tankless water heaters help you to maximize your available space while saving money.

Energy Savings

Condensing tankless water heaters provide hot water by using the remaining heat from the exhaust fumes produced by the engine. Because of the improved efficiency of the operation, operational expenses and energy savings are reduced.

Compare: Condensing Gas Tankless:ATI-540H 199,000 BTU Non-Condensing Gas Tankless:ATI-510U 199,000 BTU
Single Shower Length* Unlimited Unlimited
Showers Back-to-Back* Unlimited Unlimited
Showers at the Same Time* 3.1 showers 2.6 showers
Maximum Tub Size* Unlimited Unlimited
Continuous Hot Water check_circle_outline check_circle_outline
Space Savings check_circle_outline check_circle_outline
Energy Efficiency check_circle_outline check_circle_outline
UEF 0.93 0.82
Warranty 15 Years 15 Years
*Many factors affect the actual performance of a water heater. This represents our closest approximation of your likely experience with this water heater in your local area, but actual performance may vary depending on factors beyond our ability to control or estimate.

Water heaters manufactured by A. O. Smith are professionally installed by independent contractors in the local area. GET IN TOUCH WITH A LOCAL INSTALLER

Not sure which water heater is right for you?

Make use of our product picker tool to choose the best model for your needs. Please Assist Me in Making My Decision

Contractor Resources

  • Detailed Instructions for Setup Installing a gas tankless water heater is simple when you follow our installation instructions. See the document
  • Guide to Obtaining Resources Match the flow rate to the requirements of your customers. See the document
  • Cross-Reference Tool is an acronym that stands for Cross-Reference Tool. Look for replacement products that are NAECA-compliant. Make use of a tool.

What’s the Difference Between Condensing & Non-Condensing Tankless Water Heaters?

What Is the Difference Between Condensing and Condensing and Condensing Tankless water heaters that do not condense? Tankless water heaters that condense versus non-condensing. Mounted on the outside Navien Tankless (Navien Tankless) Tankless hot water heaters are becoming increasingly popular, and there are an expanding variety of alternatives available. Because they are tankless in nature, they do not require any additional storage space as standard water heaters do. The water in a tankless system is warmed as it passes through its heat exchanger, which is heated by combustion at a higher temperature than your typical hot water heater, resulting in more intense heating.

  • Steam, or to put it another way, water vapor, is one of these hot gases.
  • The condensation water has a pH of 3-5, making it acidic and caustic.
  • A non-condensing tankless hot water heater will send these hot gases through its vent to the outside (or out into the air if it is externally affixed to the home).
  • These gases have temperatures in the vicinity of 300 degrees Fahrenheit and must be released using non-corrosive venting materials that can withstand the high temperatures.
  • While going through the combustion process, fuel was consumed, and the resulting energy was used to heat the water, albeit not all of it.

The higher the temperature of the exhaust gases, the less energy is required to heat the water, resulting in a lower overall efficiency. Non-condensing units have efficiency ratings of roughly 80%, suggesting that around 20% of the heat is wasted and expelled.

Condensing Tankless Hot Water Heater

Condensing water heaters extract the excess heat from exhaust gases in a variety of ways, resulting in cooler exhaust gases that are typically about 100 degrees Fahrenheit (in some cases lower). As previously noted, condensation occurs as a result of the cooling of exhaust gases, in this instance within the system. It is possible to utilize a less expensive venting product since the exhaust gases are now considerably colder; most commonly, basic PVC schedule 40 is used because it can swiftly withstand the heat and corrosive nature of the exhaust gases.

  1. It should be noted that a condensing unit does not continually condense, and that the temperature and humidity of the surrounding air are crucial considerations.
  2. Because the exhaust gases have really been cooled within the unit, condensation water has now been collected within the unit itself.
  3. It must now be built of a higher-quality, non-corrosive material in order to withstand the corrosiveness of the environment; it is often made of a specific stainless steel alloy.
  4. This can be accomplished by the use of specific filters or dilution.
  5. They are slightly more expensive to construct, but in comparison to non-condensing tankless water heaters, which need the use of expensive stainless-steel venting components and are less efficient, they are comparable in price (about 80 percent ).
  6. We also specialize in leak detection; please contact us for more information.
  7. To book a visit, please call us at 704-919-1722 or complete the online form.

Condensing vs Non-Condensing Tankless Water Heater Comparison

Please keep in mind that this content may contain affiliate links. This means that, at no additional cost to you, we may gain a small profit on purchases made via our links. Condensing and non-condensing tankless water heaters are the two most common types of gas-fueled tankless water heaters. Each has its own set of pros and downsides that should be taken into consideration.

Examine the condensing versus non-condensing tankless water heater debate to understand how they differ and how they stack up against one another in terms of performance. Tankless Water Heaters vs. Traditional Water Heaters (Related)

How Water is Heated in a Tankless Water Heater

Whenever you turn on your hot water faucet, water is drawn into the system through the intake line. A flow sensor in this pipe then sends a signal to the control panel, instructing it to commence the heating procedure. Activation of the exhaust fan is followed by the opening of the gas valve and the ignition of the burner. Thermal energy is extracted from the flame and transferred to cold water that is flowing through the system’s tubing by the primary heat exchanger. Because it adds a little amount of cold when the water exits the exchange chamber, a mixing valve can assist prevent the superheated water from becoming excessively hot.

The presence of any variance results in the transmission of a signal that controls the valves, which includes a flow-regulating valve, to bring the outgoing water to the appropriate temperature.

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It’s important to note that the method varies slightly based on the system you’re using, but the main procedure is the same for all gas models.

Condensing Tankless Water Heaters

Have you ever considered how wasteful an open system may be? If you haven’t, you should. Closed systems recycle materials, but in an open system, something is constantly lost in the process of recycling materials. Condensing water heaters correct this frequent issue by using the exhaust gas to further heat the water, rather than allowing all of the warm (but not very breathable) hot air to escape unnoticed and untreated.

How They Work

Condensing systems are equipped with a second heat exchanger and are meant to recycle exhaust through the system before releasing it into the atmosphere. Despite the fact that these gases are not particularly hot (typically around 100 degrees), as they pass through the secondary exchanger, some of the heat they contain is transferred to the incoming cold water. The water is subsequently sent through the main heat exchanger, where it is heated to the required temperature using far less energy than previously.

This can help you save a little money on your water bill, but it also shows to be a drawback of this system.

The Pros

The act of recycling exhaust not only saves money on fuel and heating expenditures, but it also helps the environment. The exhaust from a gas system can reach temperatures of up to 300 degrees Fahrenheit, necessitating the use of specific materials in the flu system. As a result, the ventilation system of your water heater is likely to account for a significant amount of your total outlay. Condensing water heaters draw heat from the exhaust and use it to chill the water, allowing it to be used at much lower temperatures.

Because of this, less expensive materials may be employed in the ventilation system. The overall efficiency of a condensing type is roughly 90 percent, making it one of the most energy-efficient options available.

The Cons

When it comes to condensing tankless water heaters, corrosion is one of the most serious problems. As a result of the condensation process, the lifespan of various components is significantly reduced. A condensing water heater made of stainless steel alloys is typically the greatest option for dealing with this problem, as shown below.

Non-Condensing Tankless Water Heaters

There is a large proportion of gas-powered tankless water heaters that are non-condensing in nature. When switching from a typical tank model to one that takes use of existing ventilation, these systems are frequently the first kind that customers consider.

How They Work

Non-condensing tankless water heaters are the most basic type of gas-powered tankless water heater available. As a result, they only feature a single heat exchanger. The exhaust gasses are much hotter when they exit the unit, and they are released straight to the atmosphere rather than being looped back through the heater as previously.

The Pros

When switching from a typical tank type, it is generally possible to repurpose existing fixtures and equipment. This implies that you will spend less money on a flu system, which is often the most expensive component of most water heater systems. Furthermore, non-condensing types are less expensive than their condensing counterparts, making the first investment in a tankless water heater rather enticing. Their somewhat smaller size and the fact that they just require professional care, as opposed to other types that require both DIY and expert attention, are two further appealing characteristics.

The Cons

The exhaust from a tankless type is quite hot, and it has the potential to destroy the vents unless they are made of a more durable and expensive material such as stainless steel. If your present water heater’s flu system is older or constructed of less lasting materials, this will result in a significantly greater initial cost. These versions also have a rather low efficiency of around 80%. While this is significantly higher than the average operating cost of most tank models on the market, it still leaves plenty of potential for improvement if operational expenses are your top priority.

The Verdict: Condensing vs Non-Condensing Tankless Water Heater

Now that we’ve had a look at these two types of tankless water heaters and their specific characteristics, it’s time to make a comparison in the argument between condensing and non-condensing tankless water heaters. The following are some of the most significant categories in which the two systems differ. Although we personally lean towards the condensing side because to the fact that the technology is now somewhat ahead of other varieties, we cannot advise you on which one to choose because everyone’s requirements are a bit different.


When it comes to efficiency, condensing tankless water heaters exceed its non-condensing counterparts, achieving 90 percent efficiency compared to 80 percent efficiency for non-condensing tankless water heaters. Both alternatives are more energy efficient than electric vehicles.


Both systems emit minor quantities of harmful vapors into the atmosphere, which is one of the disadvantages of utilizing natural gas as a fuel.

Conversely, condensing units have a far lower carbon footprint than any other tankless water heater alternative currently available on the market today.


Because of the additional heat exchanger, condensing versions are often more costly than non-condensing units. Over time, the additional components may necessitate some additional maintenance due to the increased workload. While the long-term advantages outweigh the original cost in terms of utility savings, the initial outlay may be prohibitive for certain people on a limited budget. Non-condensing devices are less expensive in the short term.


When properly maintained, a gas-powered tankless water heater may easily outlast its original manufacturer’s warranty of 20 years. In both the condensing and non-condensing types, there are components that will wear out a bit more quickly in one than in the other. A high-grade, corrosion-resistant material must be used in the construction of the pipes that carry the condensation in condensing systems. These may get deteriorated over time and require replacement. Heat transfer through the exhaust ventilation of non-condensing models is significantly higher than that of condensation models, which can lead to deterioration or leaks over time.


Condensing models save even more money since they recycle their wastes to generate more heat. This byproduct, depending on how the condensation line is linked, can also be recycled back into your water lines, which can result in a minor reduction in your water costs over time.

Condensing vs. Non-Condensing Tankless Water Heaters

By recycling its waste to generate more heat, condensing versions may save even more money. This waste may also be recycled back into your water lines, which can help you save money on your water bills. It all depends on how your condensation line is linked.

Are Condensing Water Heaters Worth It? Condensing vs. Non-Condensing

Whenever utility prices become a source of frustration, you look for ways to reduce your expenditures. Switching from traditional tank water heaters to tankless water heaters is one of the most effective methods to minimize energy bills in your house. When shopping for tankless water heaters, you will have the option of choosing between condensing and non-condensing models. Condensing water heaters are a good investment since they are less expensive and have higher efficiency when compared to non-condensing heaters.

In this section, you’ll find everything you need to have the convenience of a tank water heater without having to deal with the tank.

Are Condensing Water Heaters Worth It?

When you take into consideration installation expenses as well as purchase prices, condensing water heaters are a good investment. After all, you’ll save money on your energy and water costs as a result. For the average family, condensing water heaters can cost up to $260 per year in operating costs due to their efficiency. This value is an upper estimate, with lower estimates showing that installation costs between $700 and $4600 range between $150 and $200 per square foot. Condensing water heaters are available in a variety of configurations.

  1. In addition, this is where you can gain some leeway on the installation charges.
  2. Condensing water heaters consume less energy and waste less water than traditional water heaters.
  3. For those who haven’t quite bought into the concept of condensing water heaters yet, the warranty variety may be more appealing.
  4. Because of this, the durability of condensing water heaters must be taken into consideration.

If these units are properly maintained, they may last for a very long time. They also come with warranties that range from 5 years for certain models to 15 years for others, such as Takagi water heaters, which is an added bonus.

Advantages of a Condensing Tankless Heater

The condensing tankless water heaters provide hot water as long as the cold water intake is left open on the tankless water heater. It circulates and recirculates water throughout the system, ensuring that very little is lost through leakage. The majority of the condensate produced as a by-product is utilised in the heater rather than being lost via the exhaust.

2. Cheaper Maintenance

While the condensate is acidic and may cause damage to the venting systems, the pH of the water is lower than that of citric acid. As a result, condensing tankless water heaters do not require the use of expensive venting materials to keep corrosion at bay. PVC venting systems are used in condensing water heaters, although stainless steel venting systems are used in some non-condensing water heater types. In the long term, it is less expensive to maintain a condensing tankless heater than it is to purchase one.

3. They Save Energy

During the water heating process, any excess heat created is recycled to produce additional hot water. Not only do you have continuous hot water coming out of your taps, but you also use less energy to keep the temperature at the desired level. Energy efficiency results into greater cost savings in operation and maintenance over the long term. All condensing tankless water heaters are currently being constructed to achieve efficiency ratings of more than 90 percent, which is the industry standard.

4. They are Better for Cooler Climates

Tankless condensing water heaters are the most efficient device for heating water in cold climates because of their rapid heating process. Without wasting any energy or requiring energy from any other heating systems in the house, you may raise the temperature of the water that comes out of the heater.

See also:  What Is The Best Tankless Hot Water Heater

5. Better Space Management

In general, tankless water heaters may be put in smaller places than traditional water heaters. The units have a large storage capacity without taking up a lot of space. That implies that when you replace your tank with a tankless water heater, you will save even more room.

6. Smaller Carbon Footprint

More and more companies are concentrating on solutions that do the least amount of damage to the environment. Condensing tankless water heaters consume less energy because they recycle residual heat, generate only small quantities of waste, and dispose of any waste through low-cost drainage systems, resulting in lower overall energy use. The Energy Star label is attached to the majority of units, indicating that they satisfy the standards for environmentally friendly, money-saving appliances.

7. They are Safer For Homes

Everything that happens within a tankless condensing water heater happens within the heater. There is a lower risk of electrical harm occurring. Furthermore, because it requires just a tiny amount of area to be installed, the possibility of a serious accident is minimized. With a self-contained tankless system, you can be assured that your family is secure.

Disadvantages Of a Condensing Tankless Water Heater

Even while pro-efficiency energy legislation recommends that we go light and green with condensing tankless water heaters, there are some reservations about the practice.

1. Corrosion

A somewhat acidic pH is produced by condensing tankless water heaters due to the surplus condensate they discharge. Over time, the acidity begins to chip away at the venting system’s structural integrity. It is necessary to inspect the vent system on a regular basis to ensure that it is in proper working order. You may, on the other hand, choose a condensing tankless water heater with PVC vents in order to reduce the impact of corrosion. Alternatively, you might go for a stainless steel vent system, which will be more expensive but will endure for a longer period of time.

2. High Initial Setup Costs

The installation of condensing tankless water heaters is expensive. It may cost anything from $600 for an EZ Tankless tankless to $1900 for a Rinnai model tankless water heater depending on the manufacturer. The price of each item is decided by the vending system and the size of the item. Compared to condensing tankless water heaters with stainless steel venting systems, condensing tankless water heaters with PVC venting may be more inexpensive.

3. Complicated Setup

The installation of condensing water heaters is not straightforward when switching from a traditional heating system to one that uses condensing technology. It is necessary to install new gas lines and venting systems. Based on current plumbing and electrical labor rates, the financial consequences of this new system might reach into the hundreds of dollars.

How Does a Tankless Condensing Water Heater Work?

When you require hot water, cold water is drawn into the heater through an input located at the bottom of the unit. It ignites a flame in each of the two heat exchangers in the condensing tankless water heater’s condensing tankless water heater. While passing through the secondary heat exchangers, the water is heated to a desired temperature. Any latent heat is caught and reused before it is exhausted through the vent system. The water continues to heat in the primary heat exchanger and then flows through the output pipe to reach your hot water faucets and other fixtures.

Hot water only stops flowing when you turn off the cold water supply, and it continues to flow until you need it again.

What Does a Condensing Tankless Water Heater Do?

A condensing tankless water heater is responsible for providing you with hot water at its core. The technology, on the other hand, is different. A tankless water heater provides you with continuous hot water without the extra weight and size of a traditional tank water heater. A condensing tankless water heater varies from a non-condensing tankless water heater in that it makes use of any extra heat generated by another heat exchanger located in the heating chamber. Tankless water heaters do not have a storage tank to hold water.

Condensing tankless water heaters do not use a vent to exhaust the extra energy they generate.

Not only does a condensing tankless water heater provide you with more water than a non-condensing tankless water heater, but it also does so while consuming less energy, as seen by its Uniform Energy Factor (UEF) of greater than 0.90.

Does a Condensing Water Heater Need a Drain Pan?

Condensing water tankless water heaters use condensation to heat water as it runs through the system’s intake. Water vapor is produced as a result of this heating process. As the vapor cools, it condenses and becomes a liquid. It is necessary to discharge the condensate. If your water heater is located in a place where the acidic condensate cannot drain easily to an exit, you will need to install a drain pan beneath it. Drain pans are required to be used when the heater is located within the living quarters by legislation.

Even in little volumes, condensate can accumulate in a tankless system and cause internal parts to corrode due to the acidity of the liquid.

Some high-efficiency water heaters are equipped with neutralizer agents, which reduce the acidity of the condensate.

Differences Between a CondensingNon-Condensing Water Heater

Condensing Water Heaters Non-Condensing Water Heaters
They have a primary and secondary heat exchanger Only have one heat exchanger
Lower combustion temperatures High combustion temperatures up to 356°F/ 180°C.
Recycles extra heat in the condensing heat exchanger Loses 30% of the combustion gases through the flue
Lower carbon emissions They have more carbon emissions
It costs more to buy and set up Low initial purchase costs
Lower venting system maintenance cost as most heat is recycled High venting costs
Flexible venting material such as PVC Metal venting material
They have drain pans at the bottom of the heater They don’t have drain pans

Advantages of Non-Condensing Tankless Water Heaters

Non-condensing water heaters, in contrast to their condensing counterparts, do not collect and store extra condensate. An alternative method is to let any waste vapour to evaporate and be lost to the nearby surroundings. The internal systems are not exposed to acidity, despite the fact that this eventually results in lost energy and decreased efficiency.

2. Energy Efficiency

Even though non-condensing water heaters have a lesser efficiency than condensing water heaters, they perform better than typical tank systems. Systems with an efficiency of 85 percent are a significant improvement over systems that take up valuable space, waste water, and raise utility prices significantly.

Condensing Vs. Non-Condensing Water Heater for a New Home

For all practical considerations, condensing water heaters outperform non-condensing water heaters. Any homeowner’s ultimate objective is to have the lowest possible utility expenses while yet getting the most out of their systems. Condensing water heater systems provide a variety of advantages, the most notable of which is their ability to save energy. If you are moving into a new house and do not have access to a water heater, a condensing water heater is a preferable choice. If your home currently has a non-condensing water heater, you may update to a newer model while maintaining the non-condensing feature.

Even so, if you are ready to bear the additional expense of a new venting system installation, you may convert the entire system from non-condensing to condensing.

Are Condensing Water Heaters Ideal for Large Families?

Because they are available in a variety of sizes, condensing water heaters are suitable for both large and small families. A compact condensing water heater might be beneficial for a family of three who live in a tiny space. Condensing water heaters, on the other hand, have an output rate of 9 gallons per minute, with some models reaching 11 gallons per minute, making them the ideal heating equipment for a house with four bathrooms.

With BTUs as high as 199,000 and recovery rates in excess of 250, these strong units provide a powerful punch.

What Does UEF For Condensing Water Heaters Mean?

When it comes to water heaters, the Uniform Energy Factor (UEF) is a common measure of efficiency. It enables merchants to compare water heaters by utilizing a standard number as a starting point. Every water heater is now needed to have a UEF rating in order to be compliant. It is the proportion of energy that is converted into hot water. A high UEF of 0.85 implies a high percentage of efficiency, which is beneficial. When shopping for tankless water heaters, on the other hand, you should opt for models with a UEF of 0.95 or higher.

A tankless condensing water heater with a 0.90 UEF will have a running cost of around 90 cents on the dollar.


It is common practice to test the efficiency of water heaters using the Uniform Energy Factor (UEF). It enables merchants to compare water heaters by utilizing a standard number as a starting point for comparison. Now, a UEF rating is needed for every water heater sold in the United States. Amount of energy converted to hot water is expressed as a percentage. A high UEF of 0.85 implies a high percentage of efficiency in comparison to the industry standard. When shopping for tankless water heaters, on the other hand, you should opt for models with a UEF of 0.95 or above.

It will cost around 90 cents on the dollar to run a tankless condensing water heater with a 0.90 UEF.


  • Buyer’s Guide to High-Efficiency Water Heaters
  • Condensing vs. Non-Condensing
  • Condensing vs Non-Condensing
  • Water heaters that do not require a tank
  • I’d want to know how much a tankless water heater costs.

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