What is a condensing boiler? And what difference does it make?

When buying a new boiler or replacing an outdated model with a more efficient one, homeowners may be overwhelmed by the variety of options available. However, if you’re looking for energy efficiency and cost-effectiveness, you’ll find yourself surrounded by condensing boilers. This leaves many wondering: what is a condensing boiler, and what is the difference between condensing and non-condensing boilers?

This article will provide an in-depth look at condensing boilers, including how they work, the types available, their advantages and disadvantages, and more.

Introduction to condensing boilers

In the 1970s, the initial oil crisis prompted manufacturers to rethink their options and find a cost-effective, energy-efficient solution for boilers. To address this issue, technical experts began running boilers at lower temperatures and adjusting the water temperature inside the boiler to match the temperature outside. After extensive experimentation, the first-ever condensing boiler was introduced in the 1980s.

What is a condensing boiler, and what makes it efficient?

Condensing boilers are equipped with advanced water heating technology, offering up to 95% efficiency compared to the 70–80% efficiency of non-condensing boilers. This is achieved through their condensing technology, which captures water vapour from the exhaust gases in a heat exchanger and preheats the circulating water, thus recovering the latent heat of vaporisation that would otherwise be wasted. It is important to note that for a condensing boiler to work optimally, the ideal temperature should be around 55 °C.

Today, condensing boilers are highly sought after due to their energy efficiency and cost-effectiveness, making them an excellent choice for reducing energy bills. In addition, the UK government has mandated that homeowners use boilers with condensing technology.

How do condensing boilers work?

Up to 30–50% of the heat produced by non-condensing boilers burning fuel such as oil and gas is wasted due to combustion gases escaping into the flue. These flue gases can be harmful, so they must be removed. However, these waste gases contain heat that can heat your home. This is where condensing technology comes into play.

Condensing boilers capture water vapour from the exhaust gases with the help of a large heat exchanger or two heat exchangers, depending on the type of boiler. and preheat the circulating water, thus recovering the latent heat of vaporisation that would otherwise be lost. A condensing boiler has the same heat input as a non-condensing boiler. Still, due to its ability to recycle excess heat from the water returned to the radiator, it uses less fuel while providing the same level of heating.

Advantages and Disadvantages of a Condensing Boiler

Condensing boilers are a great way to save money and waste gases. But with benefits, it also has some drawbacks that you might want to consider. Let’s discuss them in detail:

Pros

• Higher efficiency saves you money on your energy bills

As mentioned, the main advantage of a condensing boiler is its efficiency. Recycling the heat from the waste gases back into the system can significantly increase the efficiency of your central heating system by up to 90%. If you purchase a combi boiler, the efficiency can reach up to 95%.

• Lowers your carbon footprint by preserving the environment.

A non-condensing boiler not only wastes gases and affects the efficiency of your heating system, but it also releases CO2 into the environment, increasing your carbon footprint. Investing in a condensing boiler is always wise, as condensing technology will improve fuel consumption, minimise energy waste, and contribute to the environment by reducing your carbon emissions.

• Space and safety

A condensing boiler saves space and provides you with safety at the same time. Its space-saving feature results from its compact and sleek design, which does not require an additional hot water storage tank, making it easy to fit in a kitchen cupboard.

Furthermore, it is a fully sealed system that takes air from the outside with the help of a flue, as opposed to non-condensing boilers that carry air from inside the room. This safety feature limits the risk of something being sucked into the boiler’s interior.

Cons

• Expensive to maintain

With numerous operational advantages, condensing boilers also present homeowners with maintenance challenges. Repairing them requires technical expertise, which necessitates calling a Gas Safe registered engineer, whose fee can be pretty costly as repairing a condensing boiler is a complex issue.

In comparison, non-condensing boilers are less efficient but cost less to repair. Unless your old non-condensing boiler has fully broken down, you are advised not to replace it, as the condensing boiler is expensive to maintain and repair.

• A complicated system

The efficiency and advanced technology of a condensing boiler make it a complex machine to comprehend. As the acidic water is disposed of through a condensate pipe after condensation, the lines may become corroded, or, in extreme weather conditions, the condensate pipe may even freeze.

• Prone to corrosion

Condensing boilers are composed of aluminium components, making them susceptible to corrosion. As they expel water with acidic content, it is essential to be aware of the anti-freezing feature. Remember that overusing or underusing the anti-freezing part can easily damage your boiler.

Therefore, it is imperative to understand how to use the anti-freezing feature and to check the pH level every one to two years.

How do I choose the right condensing boiler?

This is the most crucial question that confounds many homeowners. This is due to their lack of understanding of a condensing boiler and its potential. But don’t worry; we will provide you with the essential factors to consider before purchasing a condensing boiler to simplify your decision-making process.

Let’s begin:

• When selecting the right boiler for your home’s central heating system, you have three main options: combi boilers, system boilers, and regular/conventional boilers. Many people ask if a condensing boiler is the same as a combi boiler, and while they are similar in that all combi boilers are condensing, there is a difference between a combi and a condensing boiler. To learn more about each type, check out our blog post on the different types of boilers.

• While making your decision to purchase a boiler, it is vital to consider the fuel type that the boiler runs on, such as electric, gas, or oil, depending on what is available in your area. It is essential to consider the availability of the fuel type in your area, as this will determine the efficiency and cost of your boiler. Additionally, it is vital to research the various fuel types to ensure that you are selecting the most suitable option for your needs.

• Weigh the advantages and disadvantages mentioned above and ask yourself if you need a condensing boiler. And can you deal with the complexities of this system?

• After the basics, compare the features of the models available. How do I do that? Simply look for the following:

• Wattage Output:

Now the critical aspect of a boiler, be it condensing or non-condensing, is the wattage rating measured in KW. Choose the ideal wattage for your home after determining your usage. The math is simple: the higher the demand, the higher the output rating.

• Warranty Period

A warranty is an important thing to consider. Anything can go wrong from installation to operating fault after buying a boiler. So remember to inquire about its period and what it covers.

• Efficiency Rating

Efficiency rating is vital to consider as the rating highlights the ability of the boiler to convert fuel into usable energy.

• Customer Review

Customer reviews are critical to consider, as they inform you about the experiences that past customers have had and give you an idea of what to expect. Read reviews on Trustpilot for both the manufacturer and the installer.

Are all new gas boilers condensing in the UK?

According to regulations from April 2005, all newly installed or replaced boilers must be gas condensing boilers and have an efficiency rating of 90% or higher. However, depending on the type of building, a Gas Safe Engineer may advise you to install a non-condensing boiler in some rare cases.

Therefore, it is recommended that you seek expert advice before replacing or installing a new boiler. They will inspect your property, inform you of the best boiler to establish, and ensure you get an efficient and cost-effective solution.

How do you know if you have a condensing boiler?

You’re not alone if you’re unsure whether your boiler is condensing or not. Many people find it difficult to determine the type of boiler they have. When you purchase a condensing boiler, you should receive a manual with instructions on how to use it. If you’re having trouble understanding the manual or have misplaced it, here are a few tips to help you out:

• Start with the basics. Check when your boiler was installed. If it was installed before 2005, it’s likely a non-condensing boiler and should be replaced.

• Next, look for the flue located outside your home. If the flue is made of metal, you have a non-condensing boiler.

• Finally, check for steam coming out of the flue. If steam is present and the pipe is made of plastic, you have a condensing boiler.

What size condensing boiler do you need, and for how long will it last?

To determine the ideal size of a boiler for your home, you should consider the number of radiators and bedrooms or bathrooms. For example, if you have a household with 2-3 bedrooms or bathrooms and ten radiators, the ideal size would be 24–30 kW. If you have a larger home with 5–6 bedrooms and 20 radiators, then the ideal size would be 35–42 kW.

The life of a boiler typically ranges from 10–15 years, although this can be extended depending on usage and maintenance. You should get a boiler cover when you replace or buy a new one. This will cover the cost of maintenance and future repairs, especially for a condensing boiler, which is a complex machine.

Cost of condensing boilers from top brands

Installation Cost of a Condensing boiler:

The installation cost will vary according to the fuel type. Gas boilers typically range from £1500 to £2200, while oil boilers may cost up to £2500 or more. Obtaining multiple quotes from different providers is recommended to get the best deal.

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Maintenance Tips:

Before we conclude our discussion, here are some maintenance tips that can help you gain a better understanding of your condensing boiler:

It is essential to have a Gas Safe Engineer inspect the heat exchanger, thoroughly clean the burner and mesh, check the electrical connections, and restart the boiler. If necessary, a system power flush should be performed to remove any built-up limescale and debris, and the condensate pipe should be cleaned and checked for any potential leaks. By following these steps, you can ensure that your condensing boiler is running optimally.

Conclusion:

To conclude, if you’re looking for a boiler replacement or purchasing a new one, then investing in a condensing boiler is the ideal solution. This article discusses the features, functioning, cost, advantages, and disadvantages of a condensing boiler and how to maintain it. Living in the UK, where cold weather can be a real challenge, it’s essential to know what a condensing boiler is and how it can make a difference in your life.

The government also encourages condensing technology to conserve energy and reduce wastage. However, in some rare cases, a Gas Safe engineer may advise you to opt for a non-condensing boiler after inspecting your property and the fuel type available in your area. Even if you have a non-condensing boiler aged between 5 and 10 years, many experts, including us, suggest sticking with your non-condensing boiler as condensing boilers can be complex.

If you have any questions or need help finding the perfect boiler for your needs, please don’t hesitate to contact us at 0345 3192 247, and one of our representatives will be happy to assist you.