Condensing vs Non-Condensing Tankless Water Heaters (Which is a Worthy Investment?)

If you have Googled tankless gas water heater options online, then you have surely come across the condensing tank water heater vs. non-condensing tank water heater.

So, what causes the hype?

Let’s dissect the meaning of the word “condense” first.

The word “condense” refers to the process of changing matters from gas or vapor into a liquid state.

If you are curious about this hype, then read the succeeding sections to have a clear understanding.

Condensing Vs. Non-Condensing Tankless Water Heater

Non-condensing

In non-condensing water heaters, the water heating process is quite straightforward.

The cold water passes through combustion. As the water passes through the burner, the water heats up very quickly, thus producing gas at a very temperature. Now, this gas is exhausted instantly. This exhausted gas can reach as high as 400 degrees Fahrenheit or about 204 degrees Celsius.

In this combustion process, more energy is consumed for heating but not all of it is used to actually heat the water.

So, where did the heating energy go?

Most of the heating energy is wasted by exhausting them out to the open. You see, non-condensing tankless water heaters have lower efficiency. The higher the temperature of the exhaust gases is (which is the case with the non-condensing heaters), the less energy is used in heating the water.

Check out the image below for guidance:

Image taken from www.etrine.com

Condensing Tankless Water Heater

The condensing tankless water heaters, on the other hand, have a more complex system but offers higher efficiency.

How?

Condensation happens when a hot gas comes in contact with a cold surface. But in a condensing tankless water heater, the high-temperature exhaust gases are extracted to produce additional heat. Therefore, it only exhausts cooler gases around 120 degrees Fahrenheit or 48.8 degrees Celsius.

In addition, since the water heats up faster, a huge amount of water actually turns into steam in an instant. The good thing with condensing tankless water heaters is that there are two heat exchangers. The other one heats up the water while the other instantly cools down the exhaust gases of the first exchanger, thus turning them into liquid again (condensation happens).

The condensation happens inside the unit, so all the heat energy is actually used to heat up the water without wasting so much. In fact, condensing tankless water heaters can achieve a high efficiency of up to 98%.

Condensing Tankless Water Heater Pros and Cons

However, the condensing water heater also has its own fair share of pros and cons. Check out the bullets below.

• Energy efficient up to 98%
• Environmentally friendly, as it emits less carbon dioxide (CO2) and nitrogen oxide (NOx)
• Have less operating and heating cost, so you actually save more in the long run
• Great heater for commercial purposes, as well as for homes with higher energy demands
• You can use a cheap PVC venting system because the exhaust gas is actually much cooler.
• Can be used both indoors and outdoors.

• A lot of the heating energy is wasted; about 20% is actually wasted.
• It required more maintenance.
• Professional help is needed during installation.
• The initial price is higher than the standard tankless water heaters.

The Verdict

All in all, it is very clear that the condensing tankless water heater is the better choice if your budget allows it.

We’d say you can still get away with the non-condensing tankless water heater if you live in tropical places in which heating water has less demand. However, if you live in colder places, a condensing tankless water heater is definitely a worth investment.