Get the Facts on Combi Boiler Installation

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    About combi boilers

    Upgrade for a new combi boiler

    Are you considering upgrading your home’s heating system? Combi boiler installation is becoming an increasingly popular choice for homeowners, offering energy efficiency, space-saving design, and an unlimited supply of hot water.

    In this comprehensive boiler guide, we will delve into everything you need to know about combination boiler installations, from understanding their components and how they work to selecting the right model and preparing for the installation process.
    Let’s get started!


    Short Summary of Boiler Replacements

      • Combi boilers offer an efficient solution for residential heating and hot water.
      • Installation should be completed by a gas or heating engineer to ensure safety, efficiency, and peak performance.
      • Financing options are available to make the cost of installation more manageable.


    new boiler installation by our engineer

    Understanding Combi Boiler’s

    Combi boilers are an ideal choice for residential hot water and heating in North London, as they combine a heat exchanger, expansion vessel, and pump to provide instant hot water. These compact units draw directly from the mains water supply, eliminating the need for a separate water storage tank and making them perfect for small-to-medium-sized homes with one bathroom.

    The gas-safe installation and process are crucial, as a proper installation ensures safety and efficient boiler performance. It’s essential to select the right model and have a Gas Safe registered engineer complete the installation, following strict protocol checks and procedures.

    Combi boilers are also condensing boilers!


    Combination Boiler Components

    Combination boilers consist of whole central heating made of an expansion vessel, pump, fan, gas valve and many other parts, all integrated into one compact unit. This design differs from a system boiler, which requires a separate hot water cylinder, as most of its main components and features are already integrated into the combination boiler itself.

    The installation of gas combi boilers typically takes around one day, but it may require additional time if new tanks need to be installed. With this one boiler system, you can enjoy the benefits of a space-saving design, instant hot water, and improved performance.

    How Combi Boilers Work

    Combi boilers utilize a gas-powered heat exchanger to rapidly heat water, which is then supplied directly to the tap at main pressure. This unique design offers several advantages, such as a longer lifespan and mains water pressure.

    The process for installing a gas boiler involves evaluating your home’s requirements, calculating the heat demand, selecting an appropriate combi boiler and preparing for the installation. Ensuring the safety of a new boiler installation is paramount, and only certified gas engineers should install it.


    A modern combi boiler with energy efficient features

    Advantages of Choosing a Combi Boiler Against System Boilers

    Combi boilers boast numerous benefits, making them an attractive choice for homeowners. Their efficiency means they consume less gas, resulting in lower energy bills.

    The space-saving design of combi boilers (like Worcester bosch combi boilers) eliminates the need for a separate hot water tank, making them perfect for small homes or properties with limited space to install boilers.

    Additionally, modern combi boilers provide an unlimited supply of hot water from the mains, ensuring you never run out of hot water when you need it. These advantages make combi boilers a popular and practical choice for many households.


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    Efficient Combi Boiler Installation


    Combi boilers are required to have an efficiency level of at least 92%, but some models can reach efficiencies of between 95% and 98%. This is significantly better than the current boiler, which can result in considerable energy and cost savings for homeowners.

    For example, upgrading from a 70% efficient conventional boiler to a 92% efficient combination boiler can save approximately £300 annually on energy bills. Furthermore, replacing an old boiler with an A-rated boiler and heating controls can save an estimated £340 and 1,500kg of carbon dioxide emissions per year.

    Space-Saving Design

    One of the major advantages of combi boilers is their compact, space-saving design.

    Unlike traditional boilers that require a separate hot and cold water tank, combi boilers are single-contained units that can typically be accommodated within a kitchen cupboard or utility room. This makes them an ideal choice for small homes or properties, as they don’t take up valuable floor space.

    Additionally, combi boilers eliminate the need for a cold water storage tank, further reducing the space required for your hot water system.


    A professional technician performing combi boiler installation to improve energy efficiency

    Assessing Your Boiler Installation Home’s Needs

    Before choosing your combi boilers, it’s important to assess your home’s heat demand to ensure you select the right model. Factors to consider include the size of your property, the hot water demand, and the mains water pressure.

    Also, our heating engineer calculates the heat loss of the property and gives you an idea about the size combi boiler size you need.

    While combi boilers are suitable for most homes, they may not be the best choice for larger properties with multiple bathrooms, as they may struggle to meet the higher hot water demand. In such cases, a more powerful combination boiler, or a system boiler may be a better option.


    Property Size and Hot Water Demand

    The size of the boiler required depends on the number of radiators and bathrooms in your home. For example, a small 24-27kW combi boiler is suitable for a 1-2 bedroom property with 1 bathroom, while a larger 35-42kW boiler is recommended for a 4 bedroom home with multiple bathrooms.
    It’s crucial to choose the right size boiler to ensure it can meet your home’s heating needs efficiently.

    Mains Water Pressure

    Mains water pressure plays a significant role in the performance of a combi boiler. If the pressure is too low, the combi boiler rates or may not receive enough cold water when multiple outlets are used simultaneously, while high water pressure can cause damage to the combi boiler.

    For optimal performance, the recommended mains water pressure for a combi boiler fitted elsewhere is between 1 and 1.2 bar. It’s essential to check the boiler requirements before selecting a combi boiler to ensure it can operate efficiently and safely.


    a gas engineer measuring the size of a combi boiler

    New Combi Boiler Installation Costs

    When planning for a combination boiler replacement, it’s important to consider the costs involved.
    The price of a new combi boiler can vary depending on several factors, such as the size and type of the boiler, the complexity of the system boiler installation itself, and the need for additional work, such as relocating the boiler, installing new tanks or re-run a new gas pipe from the gas meter.

    Generally, the cost of a combi boiler installation ranges from £2,000 to £5,000, but it’s essential to obtain quotes from reputable combi boiler installers like us to ensure you get the best price and service.



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    Factors Influencing Cost

    Several factors can influence the cost of a combi boiler installation, such as the type of boiler you choose, whether you’re replacing an existing boiler or transitioning to a different type, and whether the replacement boiler needs to be relocated to another area in your home.

    Additionally, the cost may be affected by the complexity of the installation, the size of your property, and any necessary upgrades to your existing pipework.
    It’s important to consider these factors when budgeting for your boiler installation to ensure you get the best value for your money.

    Combi Boiler Prices

    The price ranges for boiler installations vary depending on the size and type of the existing boiler used, as well as the complexity of the installation.

    For a small 24-27kW combi four boilers fitted for installation when replacing an old combi boiler with a new one, the price range is between £1,975 and £2,925.

    For a larger 35-42kW combi boiler installation when replacing an old combi boiler with a new one, the price range for new combi boiler prices is between £1,845 and £4,500. The cost range for a conventional-to-combi boiler replacement is £3,500.
    Keep in mind that these are general price ranges and can vary depending on your specific situation and location. The larger the boiler you need the more you have to pay for the boiler. The labour price does not differ a lot.


    Selecting the Right Combi Boiler

    To select the right combi boiler for your home, it’s essential to consider top brands, such as Worcester Bosch, Baxi, Vaillant, and Ideal, as they are known for their reliability, quality, and performance.

    Additionally, determining the right size (kW output) for your combination boilers is crucial in ensuring it can efficiently meet your home’s hot water and heating needs. By considering these factors, you can make an informed decision and choose the best combi boiler for your home.


    Top Combi Boiler Brands

    Popular combi boiler brands include Worcester Bosch, Vaillant, and Ideal, all known for their high-quality products and excellent performance. Worcester Bosch, for example, has been a leading presence in the British boiler industry for many years and has received numerous awards for its products and customer service.

    Vaillant, on the other hand, is a well-established brand in the European market and enjoys a highly esteemed 5-star reputation. By choosing a combi boiler from a reputable brand, you can be confident in the quality and performance of your new heating system.

    Determining the Right Size (kW Output)

    The kW output of a combi boiler directly affects its ability to meet your home’s hot water and heating needs. For example, a 24-27kW combi boiler would be suitable for a 1-2 bedroom property with 1 bathroom, while a larger 35-42kW combi boiler would be better suited for a 4 bedroom home with multiple bathrooms.


    combi boiler conversion

    Preparing for Your Combination Boiler Installation

    Before your combi boiler installation, there are several steps you need to take to ensure a smooth and successful process. These include choosing a suitable location for your new combi boiler and obtaining any necessary permits.
    Taking the time to prepare for your combi boiler installation will help ensure that the process goes smoothly and that your new central heating boiler and system perform at its best.


    Choosing a Location for Your Combi Boiler

    When selecting a location for your new combi boiler, consider factors such as cost of installation, and warranty. The ideal location should be easily accessible for maintenance and repairs, as well as being large enough to accommodate the boiler and any required pipework.

    If you need to relocate your existing boiler, keep in mind that this may incur additional labour costs and materials, increasing the overall installation cost. The average price to relocate the boiler in the same room is an extra £500.

    Understanding Efficiency Ratings

    Efficiency ratings measure the amount of energy a boiler uses to heat water and the amount of energy converted into useful heat.

    The higher the efficiency rating, the more energy-efficient the boiler is, resulting in lower gas bills. Understanding these ratings can help you make an informed decision about which boiler to purchase and how to save money on energy bills.

    Efficiency ratings are calculated using the SEDBUK (Seasonal Efficiency of Domestic Boilers in the UK) rating system, which evaluates the energy used to heat water and the energy converted into useful heat.


    A selection of top combi boiler brands

    Combi Boiler Installation Process

    The combi boiler installation process generally takes between 6-10 hours, but this can vary depending on the complexity of the installation, the size of the property, and the type of combi boiler installed.

    Key steps in the combi boiler installation cost and process include removing the existing boiler, fitting the new combi boiler, connecting the gas and water pipes, properly cleaning the central heating system and testing the existing combi boiler, to ensure it is operating safely and efficiently.

    By following these steps, you can ensure a successful and efficient combi boiler installation.


    Key Steps in the Installation Process

    During the new combi boiler installation process, our heating engineer at MML PLumbing followed several key steps to ensure a successful and efficient outcome.

    These steps include preparing the area around the existing boiler and radiators and carrying out a system flush to remove any rust or debris from the central heating system.

    Installing the new combi boiler fitting, connecting the gas and water pipes, and testing the system for safety and efficiency.

    A combi boiler installation with a technician



    Financing Options for Combi Boiler Installation

    Installing a new combi boiler can be a significant investment, but there are various financing options available to help make the cost more manageable.

    These options include payment plans, loans, and grants, which can enable you to spread the cost of the new combi boiler work installation over several years.

    By exploring these financing options, you can find a solution that fits your budget and allows you to enjoy the many benefits of a new combi boiler without putting a strain on your finances.


    Combi Boiler Installation Options

    Payment Plans


    Payment plans are a popular financing option for combi boiler installations, as they allow you to spread the cost of the installation over some time. Pay monthly deals and interest-free financing options are available, making the cost more affordable and reducing the initial outlay.

    Some companies also provide fixed online quotes for combi boiler installations, ensuring you receive the best price for the installation. By considering these payment plans, you can find a financing solution that suits your budget and helps make the next-day boiler installation more affordable.

    Loans and Grants

    In addition to payment plans, loans and grants may be available to help finance your combi boiler installation. Government-backed schemes provide free boiler grants to eligible residents, while loans can offer additional financial support for homeowners who may struggle to afford the full cost of the installation upfront.

    By exploring these financing options, you can find a solution that works for you and ensures you can enjoy the benefits of a new, energy-efficient combi boiler without breaking the bank.



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    Modern Boilers.



    In conclusion, combi boilers offer numerous advantages over traditional heating, making them an increasingly popular choice for homeowners. With their efficiency, space-saving design, and unlimited hot water supply, combi boilers can provide a reliable and cost-effective solution to your home’s heating needs. By understanding the different components and workings of new combi boilers well, assessing your home’s requirements, selecting the right model, and preparing for the installation, you can ensure a successful and efficient combi boiler installation.

    Explore financing options such as payment plans, loans, and grants to make the investment more affordable and enjoy the many benefits of a new combi boiler for years to come.


    Frequently Asked Questions


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