Condensing vs. Non-Condensing Tankless Water Heaters: Comparison

Tankless water heaters are in trend, largely because they are convenient and user-friendly. Likewise, they don’t take a massive area of your house to store the water, making them hugely popular among users. However, the question remains which one suits you best? Many people looking for upgrades often undermine the importance of looking into the difference between available options in the market and how they can help you. There are both condensing and non-condensing tankless water heaters available in the market. To make things easy for our readers we have written a detailed comparison of condensing vs. non-condensing tankless water heaters.

If you are wondering whether condensing or non-condensing water heaters are efficient, it is important that you invest some time to study both. Despite being tankless, these alternatives differ in their working mechanism and the cost involved. Hence, to save your day, I have brought together a comprehensive guide on condensing vs. non-condensing tankless water heaters that can help you in choosing which one suits you best.

What is a Tankless Heater?

As the name suggests, a tankless heater is a regular heater with no tank that stores water for you. In contrast, as the cold water flows through the pipes or heat exchangers of these units, it heats up directly at your desired temperature without the need for storage. Hence, people prefer these modern alternatives because of their low running cost and convenient application. These heaters work on the principle of combustion to keep the water at your desired temperature.

Hence, these are equipped with stainless steel heat exchangers so that when water passes through these pipes, the hot water is easily directed to your taps. As compared to traditional heaters, these come in different sizes and electricity requirements, making them hugely popular across the market. Most commonly, there are two types of tankless heaters;


Condensing Tankless Water Heater

In simple terms, a condensing tankless heater is equipped with exchangers that are designed for recycling the heat being dissipated from the system. It is also known as the closed system, primarily because it only emits vapours from the unit (that are of no use) and utilizes the recycled heat to proceed with the operation. Similarly, with these heaters, the vapours are partially cool, so there is no need to invest in an expensive venting alternative, making them convenient and affordable for the most part.

These are also equipped with PVC pipes that help the unit tackle steam and corrosion. Another heat exchanger is included in the construction, which is looped with the system, so the heat being used is coming back to the closed system before vapours are released from it. These are not particularly extremely hot, considering the fact that condensed gasses in the system cool down during the process. All in all, these heaters work on the principle of condensation, with water being neutralized in the system.

  • These units run on low electricity costs (heating and fuel cost).
  • These heaters don’t demand expensive alternatives for corrosion-resistant ventilation.
  • The gasses in the system cool down at a lower temperature.
  • These tankless heaters are highly efficient in heating up the water.
  • These are more convenient than gas-powered heaters.
  • These are not the best when it comes to durability.
  • The PVC used in heat exchangers is generally short-lived than non-condensing heaters.

Non-Condensing Tankless Water Heater

On the contrary, gas-powered or non-condensing tankless heaters are different from the previous ones as they use the traditional house’s existing venting system. These are largely the converted tankless heaters that are famous for their ability to provide a large volume of hot water. Likewise, with these heaters, steam is ventured through the system that is then cooled down outside the system as there is no principle of condensation applied.

For this system to work, it is absolutely necessary to release the steam from the system to prevent the channel from corrosion. These are powered by gas like traditional heaters and come with only one heat exchange that releases the steam, which is not being used. On the whole, these are designed with much higher temperatures and great volume capacity. For instance, these units can start from 302 degrees Fahrenheit. So, gases are hot while being released from the system as there is no loop in the system.

  • The initial investment is quite good. This is because, during the construction, you can use the already existing ventilation system which reduces the installation cost to a great extent.
  • These are small and don’t demand professional maintenance.
  • These are long-lasting and include stainless steel heat exchange containers.
  • These heaters are highly efficient in heating the water to a relatively high temperature.
  • They have relatively high running costs. You would need an expensive ventilation system to prevent steam corrosion.

Condensing vs. Non-Condensing Tankless Water Heaters: Which is More Efficient?

To answer this question, we will have to look into individual features and benefits that give us an edge over others. Hence, here are some categories that can help you in choosing which one can work for you the best;

Performance Efficiency

To start with, when it comes to performance, condensing tankless heaters absolutely have the upper hand, all thanks to their condensation mechanism. These are using recycled heat to direct the hot water in taps, making it better than its counterparts. However, there is not much difference as both of these alternatives are better than electric models when it comes to efficiency.

Investment Cost

Similarly, there is no doubt that non-condensing models tend to be a little less pricey than the condensing heater. It is primarily because you are using an existing ventilation system from the traditional heater. Also, with these models, there is no need for regular professional maintenance which reduces the investment cost to a great extent. In contrast, with condensing heaters, despite it being affordable, you still have to invest in a venting system.

Durability/ Longevity

When it comes to durability, it wouldn’t be wrong to say that gas-powered or non-condensing cars are equipped with a longer lifespan than their competitors. They are made up of stainless steel that ensures your heat exchangers are away from heat corrosion. For instance, if properly maintained, your non-condensing setup can last for 20 years without any issue. In contrast, the pipes used in condensing tankless heaters may degrade over time as PVC cannot hold high temperatures.

Running Cost

If you are thinking of saving some money, it is ideal that you go for condensing tankless water heaters. This is because they are small and recycle the heat used during the process. So, there is less fuel involved in the operation, reducing the fueling and heating costs to a great extent. Also, there is no obvious byproduct, so the ventilation also doesn’t consume power. On the contrary, non-condensing can easily reach high temperatures that would demand a certain amount of fuel and energy.

In the end, I hope that based on these basic elements, you can choose the right one.

Frequently Asked Questions

Which type of tankless water heater is more expensive?

Well, it largely depends on your needs. For instance, if you are looking for something with a low initial investment cost, it is ideal that you opt for non-condensing heaters as they are usually using the traditional setup for ventilation. However, they have a relatively bigger running cost. If you are looking for a low fuel and heating cost, condensing heaters must be preferred. This is because they are using recycled heat for the entire loop.

Which tankless heater is more durable?

Although both tankless heaters are long-lasting, non-condensing heaters clearly have the edge over others. This is primarily because the heat exchangers are made up of high-end stainless steel that prevents heat corrosion. So, if taken care of properly, these can even last you for 20 years. Condensing heaters are also quite durable; however, they demand professional maintenance after regular intervals.

Is one tankless heater better for the environment than another?

No, when it comes to toxins, there is not much difference you can find between the two. This is because both the water heaters emit water vapour and basic gasses that incorporate negligible toxic vapours in the air. So, you won’t find any adverse effects of using these heaters on the surroundings. However, if you are really sensitive, you should consider that carbon footprints are high in condensing heaters.

Final Thoughts

Wrapping up, if you are looking for an upgrade from your traditional water heater, it is absolutely important that you consider all the options available in the market. Despite the fact that both condensing and non-condensing heaters don’t require storage space for hot water, both of these have different working operations, mechanisms, and costs (investment and operational). Hence, to know which one suits you best, you must do your research beforehand.

Finally, I hope that you can choose the right one with the help of this detailed and comprehensive guide on condensing and non-condensing water heaters.

With years of experience under his belt, Adam decided to put his water heater knowledge to work. By providing high-quality content and expert guides, Adam hopes to help anyone looking for expert water heater advice.