A Practical Guide To A Condensing Boiler 2023

The cost of energy is continuously rising, and you aren’t the only one affected by it. The demand for scrubbers and filters to remove particles from the exhaust is rising. Hence, it is necessary to consider alternatives. In these scenarios, a condensing boiler promises to be a lifesaver. It’s smart, clean, and has an efficiency of 96%. Yongxing is one of the Top 3 condensing boiler manufacturers in China. We have different brands, such as Zhongxing, Yirui, Yongxing, Jinma and etc.

This article will serve as a crash course on condensing steam boiler operation, its efficiency, benefits, and drawbacks. It will be recommending the top boilers on the market for your help. Let’s get going! 

Condensing Boiler

Condensing Boiler; Working and Types

1. How Does A Condensing Boiler Work?

The condensing steam boiler is an energy-efficient steam generator, which works as follows:

Burner: The fuel is ignited by the igniter, which produces a combustion reaction in the combustion chamber and releases heat.

Flue gas flows through the flue pipe: The flue gas passes through the flue pipe and transfers the heat generated to the water in the boiler, heating the water and generating steam.

Steam separation: The steam inside the boiler is mixed with water and needs to be separated from the steam by a steam separator to prevent water droplets from entering the steam piping.

Steam Piping Conveying: The separated steam is transported out of the steam piping for heating or driving equipment.

Flue Gas Condensation: Flue gas contains a large amount of water vapor. The flue gas is cooled by passing it through a condenser so that the water vapor in it condenses into water, which is then discharged through a drain, improving the utilization of heat energy.

Flue gas emission: After the flue gas is cooled in the condenser, most of the water has been condensed and the flue gas is discharged into the atmosphere.

Through the above process, the high efficiency condensing boiler can achieve efficient energy conversion and utilization, and achieve the purpose of energy saving and consumption reduction.

Working principles

A condensing boiler employs condensing technology for greater use of the heat it produces. The gases, such as gas or oil, are discharged through a flue during the fuel burning.  These gases would be released into the atmosphere in a non-condensing boiler system, losing their heating potential.

In contrast, it recycles hot gases into the system through a heat exchanger and back into the primary circuit. The primary circuit then transfers the heat to the radiators or the hot water.

More heat is recovered from and transferred to the water that returns to the radiators in this boiler. Hence, it produces the same heat output as a non-condensing boiler while offering better energy savings. It re-uses this extra heat and uses less fuel to produce the same amount of heating as non-condensing boilers, achieving an efficiency of more than 90%.

working of condensing boiler

2. Types of Condensing Boilers

There are three major categories of condensing boilers. Let’s take a look at them.

a.  Condensing Boiler Combi

According to boiler efficiency ratings, they rank as one of the highest categories of A-rated boilers available on the market. They save space and significantly lower heating costs.

b.  System Boilers

Combi boilers and system boilers are similar in consuming water from the mains. The difference is that system boilers store hot water in a hot water cylinder and do not deliver on demand. Meanwhile, the system boilers can handle hot water needs for facilities better.

c.  Conventional Boilers

Conventional boilers are composed of a cylinder and a water storage tank. They are also called traditional, regular, or open-vent boilers. A typical boiler can provide a lot of hot water, but there are better choices than this one if you don’t have much space.

Moreover, you can use them with solar heating systems, just like system boilers. This will assist you in lowering your energy costs and environmental impact.

Condensing Steam Boiler; What You Need To Know About Them

There have been a lot of things you have been wondering about these boilers. Let’s address them.

Condensing Boiler Vs Non Condensing Boiler

Oil Condensing Boiler


Boilers with condensing technology are significantly more efficient than non-condensing boilers. Newer types can achieve efficiencies of over 90%. Boilers without condensing technology can only operate at 70–80% efficiency.

The reason a condensing system is more efficient is that it uses a “flue gas recovery system.” Meanwhile, it uses the waste heat in the flue to heat the cold water that enters the boiler.

Additionally, it uses less fuel and produces less carbon dioxide. Hence, it is more environmentally friendly.


Condensing Vs. Combi Boiler; Are They the Same?

One common question is, “Is a condensing boiler the same as a combi boiler?” Although the two names are used interchangeably, they are actually different. A boiler with condensing technology refers to the method a boiler uses to boost efficiency. 

In contrast, a combination boiler eliminates the need for storage tanks. A boiler with condensing technology is required for all new combi boiler installations. Still, it is not always a combi boiler; It may be a system boiler or a conventional boiler.

The Efficiency Of an Industrial Condensing Gas Boiler

Condensing boilers are better than non-condensing ones. Primarily because of their higher energy efficiency. Before the condensing technology, up to 30% of a boiler’s heat was lost as it was sent directly into the flue pipe.

However, condensing ones use a flue gas heat recovery system to recycle waste heat from the flue to warm the cold water entering them. This allows them to operate with higher efficiency.

Moreover, they have the highest calorific potential in terms of heating output. In contrast, regular gas or electric boilers deliver the lowest calorific value, while the condensing ones can provide an extra 10% to 15% efficiency rate through condensation.

Hence, a condensing boiler can reach an efficiency of 90-96%. This is much higher than a non-condensing system’s efficiency of 78%.

How Long do Condensing Boilers Last?

The life span of a condensing technology depends on the quality of the construction, type, and use. However,  its lifespan can be increased with proper maintenance. A Gas Safe-registered heating professional should service your boiler once a year.

Always verify the boiler’s warranty to ensure you select a high-quality product. The Yongxing Company provides you with up to five years of warranty. Also, they’re ready to provide after-sales service so that the whole installation process goes hassle-free, and you get to save money.

Condensing Boilers Pros and Cons 

Condensing boilers offer an extensive range of advantages, but it doesn’t mean they don’t have disadvantages. Let’s analyze its pros and cons and decide if it’s the right choice for you.

Advantages of a Condensing Boiler

1.  Latent Heat Recovery

The most significant benefit of condensing technology is latent heat recovery, increasing thermal efficiency. The boiler’s fuel, wood chips, has a moisture percentage of 50%. The heat exchanger recovers the moisture’s latent heat during condensation. This leads to efficiencies greater than 100% compared to the fuel’s lower heat value.

2.  Reduced Emissions

Flue gas condensers can also lower flue gas emissions, making condensing boilers more environmentally friendly. The condensate creates a film that traps big particles and dissolves the most highly dissociated inorganic substances, including chlorides and sulfuric acid. Fine particles produced during combustion significantly impact the energy sector’s pollution.

Simply put, a condensing system emits significantly less carbon dioxide than a non-condensing boiler. The installation of a new unit might result in annual carbon emissions falling by up to 1,200 kg!

3.  Reduced Energy Costs

Condensing technology boilers pre-heat cold water entering the system using heat that would have otherwise been wasted. By doing this, the units can maximize efficiency. As a result, fuel costs will be lower because less fuel is used.

Disadvantages of Condensing Boilers

Let’s have a look at the main disadvantages of a condensing technology boiler.

1.  High Maintenance Cost 

A condensing technology boiler is more complicated and requires gas-safe licensed experts, impacting boiler rates. On the other hand, non-condensing boilers are inexpensive to repair, saving you money temporarily. But, condensing technology boilers are more effective over the long run.

2.  More Complex

Given the risk of their external pipes freezing in cold weather, these condensing technology boilers can stop working. The acid concentration may also cause these boilers to corrode. Nevertheless, due to their exceptional efficiency, these boilers are still valuable.

3.  Corrosive 

Corrosion occurs by combustion products when mechanical strain is high.  This corrosion leads to cracks in low-temperature steel heat exchangers. 

However, a few factors can reduce this corrosion. This includes using corrosion-resistant materials, careful installation, and sophisticated controls.

Condensing Boiler Cost

The cost of a condensing technology boiler depends on its capacity, function, efficiency, and performance. However, for your estimate, a boiler with 1-20 t/h and a thermal efficiency of 98% can cost you $10,000. Higher-capacity condensing boilers cost you $75,000 or even above. 

Best Condensing Boiler

Since we’ve learned the basics about a condensing boiler, let’s take a look at one of the best condensing boilers available.

Oil Condensing Boiler

The oil-condensing boiler’s excellent efficiency is its best feature. It is easy to use and environmentally friendly. Despite its high quality and features, the boiler has the most affordable cost. Let’s discuss its specifications.


  • Horizontal, one-piece design to save space.
  • A larger chamber uses less energy yet heats faster
  • Thread flue pipe with a wave-shaped furnace to improve heat transmission and save fuel
  • Built-in safety measures, including explosion-proof door, to ensure safety at all times.
  • LCD screen to help keep track of how the boiler is working
  • You can link multiple boilers and determine the load for each accordingly
  • Condensing waste heat recovery devise to ensure maximum use of energy.

Oil Condensing Boiler


Recently, there has been a huge demand for condensing boilers. primarily because they use less energy and are more efficient. Most manufacturers prefer them since they are easy to use and safe for the environment.  The primary cause of their increased efficiency is that it recovers the gases through a flue recovery system.

A condensing technology boiler also offers various advantages. For example, latent heat recovery and a small carbon footprint. There are a few drawbacks to them as well, though. They include corrosion and high maintenance costs.

Last but not least, the cost of a condensing boiler depends on its functionality, capacity, and efficiency. However, make sure to buy from reputable manufacturers to guarantee you get the most out of your purchase. Read more about our condensing boiler sale.

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