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  • System Boiler Replacement

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  • System Boiler Replacement

    Updated: April 11, 2024

    System boilers are well-suited for homes with significant hot water requirements. When considering a system boiler replacement, various tasks may be involved, with the complexity varying depending on the unique characteristics of each home.

    Why should you replace your system boiler?

    Condensing technology has become a mandatory standard for all modern boilers since 2005, making it a crucial feature of new system boilers. Compared to non-condensing boilers, which can be significantly less efficient, modern condensing boilers boast efficiency ratings up to 30% higher. This efficiency boost is achieved by capturing and utilizing heat energy that would otherwise be lost through the flue pipe in older, non-condensing models.

    By harnessing condensing technology, boilers can achieve impressive efficiency rates ranging from 92 to 99%. However, even boilers equipped with condensing technology may experience a decline in efficiency over time. In such cases, replacing the boiler not only ensures continued energy savings but also helps avoid potential breakdowns and costly repairs.

    Several indicators suggest the need for a boiler replacement. These include insufficient hot water or heating output, frequent maintenance requirements, and ongoing repair expenses. Continuous repairs can quickly become financially burdensome, making the investment in a new boiler a more cost-effective solution in the long run.

    Moreover, an inefficient system boiler can lead to increased energy bills, further emphasizing the importance of timely replacement. Preventing energy waste and maximizing cost savings can be achieved simply by upgrading to a newer, more efficient boiler model.

    What are the benefits of replacing an old system boiler?

    Replacing your old boiler offers numerous benefits, including enhanced comfort and optimal heating performance. By upgrading to a newer generation boiler, you gain access to advanced technology that improves efficiency and reliability.

    However, if you observe any signs indicating potential safety hazards with your boiler, it’s crucial to prioritize safety. In case of detecting gas odors or any other concerning signs, immediately switch off the boiler and seek assistance from a licensed Gas Safe Engineer. Prompt action ensures the safety of your household and prevents potential accidents or hazards.

    When should I replace my system boiler?

    Modern boilers can last as long as 10 to 15 years. Some boilers can last for 20 years but they will be prone to having various issues and their efficiency will decrease in time. In some cases getting a new boiler is more cost-effective than expensive repairs. 

    What to consider before replacing a system boiler

    Once the decision to replace your boiler has been made, it’s important to consider what the installation process entails, taking into account your existing heating system.

    If you opt for a like-for-like boiler swap, where you’re replacing your current system boiler with a new one, the installation process becomes more streamlined and efficient. This can save you both time and effort, as well as reduce installation costs. With this approach, components such as pipes and the hot water cylinder can remain in place, requiring only the replacement of the boiler unit itself.

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    replacing a system boiler

    Replacing your regular boiler with a system boiler

    When transitioning from a regular boiler to a system boiler, additional work becomes necessary. This includes removing the cold water feed tank from your loft and likely involves additional pipework. While these tasks may incur extra costs, they represent a worthwhile investment in the long term.

    System boilers offer several advantages, including the ability to meet high levels of hot water demand, maintain consistent water pressure, and save space in your home. However, before committing to this replacement, it’s advisable to consult a heating engineer. They can assess whether your existing pipework and radiators are capable of handling the increased water pressure associated with a system boiler. This precaution ensures a smooth and successful transition to your new heating system.

    Replacing your combi boiler with a system boiler

    When upgrading from a combi boiler to a system boiler, it’s important to consider the need for a hot water cylinder. Ensure that you have adequate space in your home to accommodate the cylinder before proceeding with your plans.

    It’s worth noting that a combi boiler is typically unable to support multiple bathrooms simultaneously. If multiple showers or taps are used concurrently, you may experience a drop in water pressure. While some combi boiler models can handle multiple bathrooms, they often consume more energy to do so.

    In summary, a system boiler is better suited for medium to large homes with multiple bathrooms due to its capacity to store hot water in a dedicated cylinder. This allows for consistent water pressure and hot water supply throughout the household.

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    How much does a new system boiler cost?

    A new system boiler can cost between £500 – £1,500. And some premium models can cost up to £2,800.

    Which system boiler should I get?

    To select the system boiler that best suits your home, it’s essential to estimate your home’s energy demand accurately. This involves assessing factors such as the size of your property, the number of occupants, and your typical hot water usage patterns. Once you have an estimate of your energy demand, you can match it with the appropriate boiler size, measured in kilowatts (kW).

    Choosing the right-sized boiler is crucial to avoid energy wastage. An oversized boiler may lead to unnecessary energy consumption and higher operating costs, while an undersized boiler may struggle to meet your hot water demands efficiently. By selecting the correct boiler size, you can ensure optimal energy efficiency and comfort in your home.

    Read about: What is the best system boiler?

    Output size of your system boiler

    You will be able to estimate the size of the boiler you need by the number of radiators you have in your home. 

    Number of radiatorsOutput size
    10 radiators9-18 kW
    15 radiators18-26 kW
    Over 20 radiators 27-40 kW

    Which hot water cylinder should I get?

    Hot water cylinders are typically constructed from copper or stainless steel, and they generally have a lifespan of 8-12 years. One of the primary advantages of having a hot water cylinder is its ability to store hot water, ensuring immediate availability even when multiple outlets are in use simultaneously, eliminating the need to wait for water to heat up.

    The capacity of a hot water cylinder depends on the size of your home and can range from 120 to 300 litres.

    There are two main types of hot water cylinders: vented and unvented. Vented cylinders receive water from a cold water tank located in the loft of your home, relying on gravity for water supply. In contrast, unvented cylinders are directly fed from the mains water supply, eliminating the need for a cold water tank. System boilers typically use unvented cylinders, which are preferable in areas with high water pressure, ensuring optimal performance of the boiler system.

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    Are system boilers suitable for large homes?

    System boilers are very convenient in large homes with high demand for hot water. 

    Are system boilers efficient?

    Yes, they are. System boilers can reach an efficiency rate of 94%. 

    What is the difference between a regular and a system boiler?

    System boilers don’t need as much space as regular boilers because they only require space for the boiler and the hot water cylinder. On the other hand, a regular boiler requires a cold water tank. In conclusion, system boilers can save you some space and due to having less part they will require less maintenance.

    Do system boilers use gas or electricity?

    System boilers have a heat exchanger that can provide hot water for your home. This heat exchanger takes its energy from burning fuel. With an electric system boiler, an electric element is used for heating the water.