Condensing Vs. Non-Condensing Tankless Water Heater

Bathroom, Comparison, Tankless Water Heater

Should I Buy Condensing Or Non-Condensing Tankless Water Heater
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Well, in this post, I would be walking you through in and out of the Condensing Vs. Non-Condensing Tankless Water Heater in order to help you make an informed buying decision.

Furthermore, I would also be responding to the queries related to Condensing Vs. Non-Condensing Tankless Water Heater to help you clear your doubts before you make a purchase.

In case of a doubt or a query feel free to reach out to us via the contact form and we would be more than happy to assist you.

So, without any further ado, let’s begin…

Condensing Vs. Non-Condensing | Comparison Chart

The comparison chart is self-explanatory and will help you in differentiating one from the other.

Condensing Water Heaters   Non-Condensing Water Heaters
 Equipped with primary and secondary heat exchangers Comprise of a single heat exchanger
 The combustion temperatures are lower High combustion temperatures up to 356°F/ 180°C. 
 It recycles the extra heat in the condensing heat exchanger Loses 30% of the combustion gases through the flue
 Lower carbon emissions Comparatively higher carbon emissions
 Higher upfront cost Lower upfront cost
Lower venting system maintenance cost since most of the heat is recycled Higher venting cost
Equipped with drain pans at the bottom of the heaterThey don’t have drain pans
 Flexible venting material such as PVC Metal venting material

Does Rinnai makes a condensing tankless water heater?

Yes, Rinnai makes a condensing tankless water heater that comes from the “ULTRA SERIES”.

The ultra series offers the most advanced and efficient Rinnai tankless water heaters.

Moreover, the condensing models have the same modern and stylish look as other tankless and non-condensing models.

When it comes to installation, these little beasts come with a flexible option, that is, you can install them either inside or outside your home whichever works for you.

Well, the ultra-high energy efficiency reaching a high 0.96 energy factor (EF), ultra-low NOx gas emission, recirculation, advanced electronics, and smart technology are some of the features that put a Rinnai condensing tankless water heater in a different league altogether.

To a larger extent, for high efficiency and performance, the credit goes to the Rinnai condensing technology that utilizes two heat exchangers, that is, the copper heat exchanger derives its energy from the gas burner while the stainless steel counterpart gets its energy from the exhaust fuel gases.

Stainless steel is used for the secondary heat exchanger because it is exposed to the acidic nature of condensate.

You can expect an efficiency of up to 0.82 from a standard tankless water heater.

On the other hand, condensing technology results in higher efficiency of up to 0.95-0.96.

Which is the best condensing tankless water heater for the money?

Does a condensing tankless water heater need a drain?

Quite often we’re exposed to the question, does a condensing tankless water heater needs a drain and so today we’ve decided to end this age-old debate by the means of

I would be throwing light on every aspect so that most of your doubts are cleared right away if NOT all.

Does it make sense?

Well, if you own a condensing tankless water heater then you must be aware of the fact that your installer would’ve included a drainage system in order to drain your water heater.

A drainage system is required by a tankless water heater in order to expedite the condensation process.

Almost all the condensing tankless water heaters have drain pans at the bottom of the heater.

Condensation is a phenomenon in which gas turns to liquid and the latter is called condensate.

You might be wondering what actually happens inside a condensing tankless water heater, right?

To be honest, inside a condensing tankless water heater, the combustion process superheats the water that enters the shower, sink, or even faucet.

It’s a known fact that water vapor is a byproduct of combustion, although, in this case, the vapor contains elements such as methane, nitrogen, and oxygen.

The problem with the vapor is that when it cools to the dew point temperature it forms condensate which MUST be drained at any cost.

As discussed earlier also, a condensing tankless water heater is comprised of two heat exchangers, that is, primary, and secondary.

The main function of the secondary heat exchanger is to extract heat from combustion gas to enhance energy efficiency so when the gas rises up the flue, it cools enough to form condensate inside the unit.

Are we on the same page?

Moreover, if you’ve noticed condensate coming out of your condensing tankless unit then the probability is quite high that it’s already set up to drain in compliance with local plumbing codes.

Also, it’s the sole responsibility of the contractor to take condensate removal into account when installing a high-efficiency unit.

Is a condensing water heater worth it?

Definitely, condensing water heaters are worth it and there are numerous reasons for it.

To be honest, as compared to a non-condensing water heater, a condensing one is more efficient as well as less costly.

Not only will it improve your water heating efficiency up to 95 percent but it also will drive down your energy uses as well as contribute less to environmental degradation.

Well, a good quality condensing water heater will cost you in the range of $150 and $300.

The installation cost is additional and would be roughly in the range of $700 and $2000.

I personally like the fact that condensing water heaters give you multiple options to choose from including gas, propane, and electric powered units.

On top of it, these little beasts will use less energy as well as reduce water wastage significantly.

And, the best part is, the US government is encouraging the use of a condensing water heater by including it in a $300 federal tax credit program for gas-powered systems which is definitely something to brag about, isn’t it?

Most of the condensing water heaters available on the market currently have a warranty in the range of 5 and 15 years which clearly depicts the trust and confidence of the manufacturers in its offering.

Correct me, if I’m wrong.

Some of the popular tankless water heaters that we’ve on our list are Rheem, Rinnai, Takagi, EcoSmart, etc.

Who makes the BEST tankless water heaters?

Advantages & Disadvantages of a Condensing Water Heater

Moving further, I would be discussing both the advantages and disadvantages of a condensing tankless water heater in order to help you make an informed buying decision.

Does it make sense?


We would only be discussing the top advantages that a condensing water heater possesses.

Perfect for Cold Climatic Conditions

Yes, you heard it, right.

A condensing water heater is perfect for cold climatic conditions thanks to the quick heating mechanism that it is equipped with.

Moreover, depending upon your requirement you can increase the water temperature that comes out of the heater without wasting any energy or pulling energy from any other heating system in the house.

Better Space Management

The good thing about any tankless water heater including Rtex-18 is that they require comparatively less space for their installation.

Some tankless heater models can be installed on the wall itself so that you can use the floor space for some other useful work, interesting, isn’t it?

In simple words, replacing a conventional tank-style water heater with a tankless counterpart will definitely save you a good amount of space that can be utilized for other purposes.

Safer for Homes

A condensing tankless water heater is uniquely designed in such a way that all the heating mechanism is placed inside the unit so the threat to the external environment is minimal.

In short, the chances of electric damage are very less.

And, as we all know that it can be installed in small and compact space so the risk of a major accident is comparatively less.

Lesser Carbon Footprint

I’m assuming that you’re aware of the fact that more and more companies have started to focus on systems that are known to inflict less damage to the environment.

Many of you might be wondering why a condensing tankless water heater waste less energy, right?

It is because they recycle residual heat, produce negligible amounts of waste, and the best part is, any wastage is safely disposed of into the low-cost drainage system.

Always look for a condensing hot water heater that comes with an ENERGY STAR.

An energy-star-rated water heater is not only environmentally friendly but also cost-saving.

Saves Energy

Of course, one of the main reasons for a condensing tankless water heater is its ability to save energy tangibly.

Excess heat that is generated during heating the water isn’t wasted rather used for heating water, thanks to the mechanism used in the unit.

The unit helps you to maintain hot water in your faucet by using less energy resulting in more cost-saving in both operation and maintenance.

I hope that most of you would be aware of the fact that nowadays, almost all the condensing tankless water heaters are manufactured to meet efficiency scores of more than 90 percent.

On the other hand, a non-condensing water heater, in general, operates at 80 percent or slightly above.

Cost-Effective Maintenance

The thing that I really like about a condensing tankless water heater is that it doesn’t require an expensive venting material in order to prevent corrosion.

In general, condensing water heaters comprise PVC venting systems.

In layman’s terms, a condensing water heater is easy to maintain and wouldn’t cost you a fortune.

Moreover, even though you’re a first-time buyer you can expedite the maintenance process on your own if you’ve got prior experience in plumbing.

You wouldn’t be needing costly equipment to maintain your condensing water heater.

Instant Water Supply

A condensing water heater can provide you with instant hot water thanks to the on-demand heating mechanism used by the unit.

Since the water is heater instantly and on-demand so heat loss to the environment is minimal which isn’t the case with a traditional tank-styled water heater.

The unit is capable of providing you with a theoretically endless supply of hot water because of its ability to heat the water when required.


It’s really important to have a clear idea about the disadvantages of a condensing hot water heater as it will help you in making an informed purchase decision.

Like any other product, a condensing water heater also has its own set of disadvantages.


Unfortunately, a condensing tankless water heater drains excessive condensate with a slightly acidic pH.

So, over a period of time, the acidity starts eating away the area in and around the venting system resulting in a decreased performance and lifespan.

It is solely your responsibility to ensure that the venting system is in good working condition.

However, the impact of corrosion can be drastically reduced by opting for a tankless condensing heater that comes with PVC vents.

Another feasible solution would be to opt for a stainless steel vent system.

Though it may cost slightly more but will definitely last longer.

Relatively Higher Upfront Cost

Trust me, the relatively higher upfront cost is one of the main reasons why my clients opt for a non-condensing water heater.

The price of the units varies in the range of $500 and $2000 and is determined by the venting system, technology used, and of course, size.

A condensing unit that comes with PVC venting is more affordable as compared to the one that is equipped with a stainless steel venting system.

Complicated Setup

As compared to a traditional tank-styled water heater, a condensing counterpart is difficult to install.

In fact, you’ll have to put in new gas lines and venting installations.

If you don’t have prior experience in plumbing or setting up a condensing water heater then you would be needing the help of a plumber and an electrician which will definitely surge the installation cost.

Advantages & Disadvantages of Non-Condensing Tankless Water Heaters

By knowing the advantages and disadvantages of a Non-Condensing tankless water heater it would be easy for you to do the comparison and make an informed buying decision, isn’t it?


In general, all the non-condensing heaters come with mainly two advantages that are listed below.

Energy Efficient

You would be astonished to know that though a non-condensing heater is less efficient than its condensing counterpart still it is far better than conventional water heaters.

You can expect the efficiency to be in the range of 80 to 85 percent in spite of the unit wasting extra water and driving utility costs higher.

Quick Drainage

The good thing about a non-condensing water heater is that it doesn’t store excess condensate which isn’t the case with a condensing counterpart.

The water vapor dissipates quickly and gets lost in the environment.

Of course, it’s a trade-off.

The internal system will not get exposed to acidity but at the same time, the unit will lead to wasted energy and less efficiency.


Like any other product a non-condensing tankless water heater definitely has its share of disadvantages.

Let’s have a quick look at each one of them.

High Combustion Temperature

As compared to a condensing water heater, a non-condensing one comes with a high combustion temperature that can surge up to 356°F/ 180°C. 

Single Heat Exchanger

Since a non-condensing water heater is strictly restricted to a single heat exchanger so the performance can’t be scaled up which isn’t the case with a condensing water heater that has both primary and secondary heat exchangers.

Wrapping Up

First and foremost, I would like to thank you for being with us till the end.

Secondly, I would like to bring to your notice that I along with my core team have put loads and loads of effort into coming up with this idiosyncratic superlative piece of information.

And, in case, you liked our effort and want to appreciate us then please do share this post with like-minded people and the ones who are in search of it.

After all, sharing is caring, isn’t it?

So, should I buy a condensing or a non-condensing tankless water heater?

Well, to be honest, both are good in their own sense and for the same reason, I’ve discussed the advantages and disadvantages of both types.

However, I’ll prefer a condensing tankless water heater over a non-condensing counterpart.

Do let us know in the comment section about your view on our post.

That’s all, as of now :):)

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