Condensing Vs Non Condensing Boiler; Which One Is The Best?

Condensing Boiler

With the rise in energy prices every day, it has become necessary to consider alternatives to non condensing boilers. Plus, there’s a global demand to lower your carbon footprint. It’s when the need for a condensing boiler arises.

These boilers provide various advantages, including low emissions, reduced energy bills, and high efficiency. Yet, there’s a lot you need to know before making a decision. Let’s have a detailed look at condensing vs non condensing boiler to decide which one is the best.

Condensing Vs Non condensing Boiler

The major difference between condensing and non-condensing boilers is their efficiency. Condensing boilers can achieve up to 96% efficiency, while non-condensing boilers only reach 78%. Yet, there are many other differences as well. Let’s have a look at the table to understand better.

Non-condensing  Condensing 
Cost efficiency  Lower initial cost, but expensive venting
High initial cost, but cost-effective in the long run
Energy efficiency  78% efficient  99% efficient 
Carbon footprint per year 7.95 tonnes of CO2 5.2 tonnes of CO2
Combustion temperature 120 – 180°C 50-60°C
Heat exchanger  1 heat exchanger  One or more heat exchangers with more extensive surface area
Recycling of gas 30% of the heat is lost due to combustion gases going into the flue. The condensing heat exchanger recycles exhaust gas.

condensing boilers for sale

Condensing Vs Non condensing Boiler Efficiency

The workings of both boilers are quite similar. They generate steam through combustion, which is distributed by radiators or an in-floor radiant heating system.

However, a non condensing boiler wastes the heat by exhausting the water vapor. In the case of a condensing boiler, this heat is recovered and returned to the boiler. This way, condensing boiler produces the same amount of heat with less fuel. Same comfort, less fuel, and improved efficiency

For a better understanding, consider the boiler’s Annual Fuel Utilization Efficiency (AFUE) rating, indicating its efficiency. The AFUE for a non-condensing boiler is typically 70–80%. More efficient models reach up to 85% AFUE.

However, the AFUE for condensing boilers is from 90 to 96%, which is 12% more! Some condensing boiler manufacturers claim it’s as high as 98% AFUE on specific types. 

Working Principle of A Condensing Boiler

how does a condensing boiler work

The main question you might ask is, “How does a condensing boiler work and how to choose condensing steam boiler?” Let’s answer this question in detail.

In simple words, a condensing boiler uses condensing technology to make the best use of the heat it produces. The fuel is the same for the condensing boiler, that is, either gas or oil.

What happens is that a non condensing boiler releases exhaust fumes that emit from the flue. However, a condensing boiler takes these hot gases and delivers them to the system’s primary circuit. Then the primary circuit either sends this heat to a heating circuit or hot water. 

Advantages and Disadvantages of Condensing Boilers 

Want to replace your non-condensing boilers with condensing ones? It’s best to look at the advantages and disadvantages to decide if condensing boilers are worth your money or not.

Advantages Of Condensing Boilers

1. Latent Heat Recovery

It is the main advantage of condensing boilers. Basically, most fuels, like wood chips, have a 50% moisture content. A non condensing boiler does not utilize this moisture, wasting this latent heat.

In contrast, a condensing boiler effectively recovers this heat through the heat exchanger. This allows it to produce more heat with the same amount of fuel and achieve higher efficiency. 

2. Lower Bills

Since condensing boilers are more efficient, you will have lower fuel bills. Higher efficiency means lower fuel costs. This is crucial considering the recent increases in fuel prices. Installing a more efficient boiler, such as a condensing one, can significantly lower your bills. As a result, your products will yield more profits.

3. Reduced Carbon Footprint

It might not be possible for you to switch to renewable energy. Yet, you may make a difference by installing a more efficient boiler.

A condensing boiler emits less carbon dioxide than any non-condensing boiler. Surprisingly, installing a new unit might reduce annual carbon emissions by 1,200 kg!

Additionally, condensing boilers often have lower NOX emissions (pollutants) than older models. This is because of the new burner technologies that optimize the combustion process.

One example of this is the Flue Gas Recovery System which is the prime reason why condensing boilers have greater efficiency.

4. Geater Safety

Condensing boilers are properly sealed for heat insulation. They draw air directly from the outside of the space they are installed in and exhaust it outside through a flue pipe. This ensures that there is no chance of contact with any dangerous substances.

Condensing boilers are also equipped with safety features like thermostats and pressure relief valves. This enables them to shut down immediately in the event of a failure. However, a condensing boiler doesn’t offer you these features.

Disadvantages of Condensing Boilers

disadvantages of condensing boilers

The benefits outweigh the disadvantages. Still, you need to consider these disadvantages before replacing your non-condensing boilers. Some disadvantages might be a deal-breaker for you, which isn’t the case usually. However, they are worth knowing to make an informed decision.

1. Difficult to Maintain

The design of a condensing boiler is more complicated than that of non-condensing models. The systems that power these boilers are much more complex, and therefore, not all can do their maintenance. It requires a professional to maintain your condensing boiler properly.

Additionally, in cold temperatures, certain condensing boilers may stop working when the external pipes freeze. Yet there are short-term solutions to this issue.

2. More Prone to Corrosion

Corrosion is another common drawback to condensing boilers. After extended use, the acid condensate that builds in the boiler lead may cause problems. Yet, given how much more efficient condensing boilers are, this danger is minor.

3. Cost implications 

Undoubtedly, installing a new boiler requires a good amount of money. But the cost of installing a condensing boiler is even higher, given its complex design. In addition, the parts of condensing boilers are expensive, making maintenance costly. 

Yet, condensing boilers can save you lots of money because of their improved fuel efficiency and longer lifespans. They are, therefore, ultimately the best option for your industry, even though they are initially expensive. Still, check the above drawbacks and see if they are deal-breakers for you.

Replacing Non-condensing Boiler

Did you decide to replace your boiler finally? Well, now it’s time you know things to consider before buying. Knowing your product will make you confident while buying. Also, you will buy the best product since you understand it.

Total Investment Cost

Installing a condensing boiler typically costs between $10,000 and $15,000. However, the amount could vary depending on the size of your plant. Plus, the size of the boiler, the number of zones, and pipe adjustments during replacement work also affect the cost. 

On the other hand, non-condensing systems cost between $8,000 and $12,000. Again, a lot depends on the details of the construction site. They often have a longer lifespan and need less maintenance. However, condensing units need less fuel than conventional boilers. 

Installation Difference

Non-condensing units can be directly vented into regular chimneys without cost. However, the materials for condensing unit venting must be corrosion-resistant. Polypropylene venting material is one such example. 

Besides, you should follow the venting regulations at all federal, state, and local levels. This is because the permitted materials vary based on the authority. Moreover, condensing items need a condensate neutralizer kit to dispose of the condensate. 

Best Condensing And Non-condensing Boiler

To ensure you choose the right boiler for yourself, we’ve shortlisted two boilers with the highest quality and most affordable prices. Let’s take a look at their features.

Best Non-condensing Gas Boiler

best non condensing gas boiler

It offers the highest thermal efficiency with the least fuel consumption. Also, the company provides customization based on your industrial requirements. Yet, these aren’t the only selling points it has. Here are some of its highlighting features:


  • Leak-free design, safe operation
  • 100% stainless steel design to avoid corrosion and explosions
  • 86% efficiency
  • 25 years of warranty 
  • Free installation as an after-sales service

Best Industrial Condensing Gas Boilers

best condensing boilers

It offers high thermal efficiency, very low emissions, and the most affordable price. Plus, you’ll get the installation service to ensure a smooth installation.


  • Offers 98% efficiency
  • Generates high-temperature steam according to different applications
  • The rated evaporation is 1-25 t/h
  • ISO9001 and ASME certified
  • Reduced emissions 
  • Lower power consumption
  • Free Installation as an after-sales service


Let’s revisit the question; Condensing vs non condensing boiler; which one is the best? In the long run, condensing boilers serve the best. The main reason for this is its increased efficiency. Moreover, there’s a global demand to reduce your carbon footprint, and a high efficiency condensing boiler does just that. It’s a win-win situation.

Lastly, you can look at the boilers mentioned above before deciding. For your help, our company offers free installation as an after-sale service as a gift to make the whole process hassle-free. Not just this, you’ll get the most affordable prices and years of warranty. So what’s stopping you? Shop right away!

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