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Last updated: 7th May, 2024


Combi Boiler Cost: Worth Every Penny for Your Home

Combi Boiler Cost: Worth Every Penny for Your Home

Key takeaways

  • Combi boilers provide efficient heating and hot water from one unit.
  • Initial costs can be offset by long-term savings on energy bills.
  • Smart technology in modern combi boilers enhances control and efficiency.

modern combi boilers offer the potential for significant savings on energy bills, thanks to their high efficiency.

Deciding on the best heating system for a home is a significant decision that homeowners face, and combi boilers are a popular choice for their ability to provide both central heating and hot water without the need for a separate tank. The cost of a combi boiler is a major consideration; however, it represents a sound investment for many.

These boilers are known for their energy efficiency and compact size, making them particularly suitable for smaller homes and flats where space is at a premium.

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The initial outlay for a combi boiler can range broadly, typically between £500 and £3,000, depending on factors like size, brand, and included features. While the investment may seem substantial, modern combi boilers offer the potential for significant savings on energy bills, thanks to their high efficiency.

Additionally, with advancements in technology, many combi boilers now come equipped with smart controls, allowing homeowners to manage their heating remotely which can further drive down operational costs.

Understanding Combi Boilers:

In exploring the efficient and space-saving solution for home heating and hot water supply, combi boilers emerge as a stand-out option. They integrate two major household functions into a single appliance, promising both convenience and cost-effectiveness.

What Is a Combi Boiler?

A combi boiler, short for combination boiler, is an ingenious solution that combines a water heater and a central heating boiler into one compact unit. Unlike traditional systems, combi boilers require no separate hot water tank, saving ample space and installation complexity in smaller British homes. They operate by instantly heating water directly from the mains when a hot water tap is turned on, ensuring efficient energy use and on-demand hot water.

Benefits of Combi Boilers

The advantages of combi boilers are numerous. They provide a continuous supply of hot water on demand, therefore the risk of running out is minimal. Space-saving is inherent, as the absence of a hot water cylinder or cold water storage tank frees up room in the property. In terms of energy, combi boilers are typically fuel-efficient; they only heat the water that is being used. For those concerned with their carbon footprint, such boilers can reduce household energy consumption and consequently, CO2 emissions.

  • Efficient: No wasted energy in heating unused water

  • Compact: Ideal for smaller spaces without room for a cylinder

  • Economical: Potential savings on heating bills due to efficiency

Types of Combi Boilers

Combi boilers can be differentiated by the type of fuel they use: gas, oil, or electric.

  • Gas Combi Boilers: These are the most common types in the UK, popular for their efficiency and lower operational costs. They use natural gas and are suited to homes connected to the gas network.

  • Oil Combi Boilers: A practical choice for properties that are not connected to the gas grid; these rely on stored oil as their fuel source.

  • Electric Combi Boilers: Ideal for properties without gas or oil supply, electric boilers offer an alternative but can be more expensive to run due to higher electricity prices.

Each type caters to different needs, locations and budgetary considerations, and it is imperative to choose one that aligns with individual home heating requirements.

Combi Boiler Costs Explained

Selecting the right combi boiler for your home constitutes more than a mere purchase; it represents a long-term investment. Understanding the costs involved is pivotal to making an informed decision that aligns with your needs and budget.

New Combi Boiler Costs

Boilers can be a daunting purchase for many people as they’re an appliance with a lot of responsibility, providing heat for you and your family is something you want to get right. Boilers aren’t exactly a quickly disposable item either, potentially lasting you a decade.

Boiler costs can be split into two segments: the first is the actual boiler itself (unit price), and the second is the cost of the boiler being installed (set up) in your property by an expert engineer. 

Here at iHeat, we want to remove all of this undue stress and make the decision making process of upgrading to a new central heating system, as easy as possible.

Boiler costs can vary depending on a number of factors including their brand, model, fuel, output, warranty, labour and installation type. Typically a new boiler will cost between £1,845 and £3,500, below is a list of average boiler installations offered by iHeat (intended as a guide only).

Installation Type

Price (inc VAT)

Combi to combi swap


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System to combi conversion


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New boiler install


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Back boiler to a combi


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Long-Term Savings Potential

Investing in a new combi boiler can lead to significant savings on energy bills. The initial cost includes the price of the boiler itself, which varies depending on boiler brand and boiler type. Renowned brands such as Vaillant, Worcester, Viessmann, and Baxi may command higher upfront costs; however, the superior efficiency of these boilers could result in lower energy costs over time. Installation costs also contribute to the overall expense, encompassing labour, VAT, and sometimes additional materials.

Disparate factors, from the complexity of the installation to the choice of finance options, can affect the end sum. For instance, choosing a top-tier brand like Vaillant coupled with complex installation requirements will likely be at the upper end of the price spectrum compared to opting for a Baxi boiler with a more straightforward fitting process.

However, the up-front cost should be gauged against potential savings. Modern combi boilers are energy-efficient units, which means they consume less fuel to produce the same amount of heat compared to older units, suggesting long-term cost-effectiveness. By reducing energy waste, homeowners might perceive a decrease in energy bills, contributing to savings year after year.

Moreover, certain combi boilers might qualify for grants, offering homeowners an avenue to mitigate initial outlays. It's advisable to solicit multiple free quotes and investigate any available grant to ensure the best financial deal. While the new boiler cost might seem steep at first glance, the aggregate saving over the boiler's lifespan can render it a valuable purchase.

To accurately budget for a new combi boiler, homeowners should consider acquiring quotes that include all costs—boiler, labour, and VAT—with an understanding that opting for reputable brands, while potentially more costly upfront, may enhance the likelihood of long-term savings.

Choosing the Right Combi Boiler for Your Home

Selecting an appropriate combi boiler is critical to ensure efficient heating and hot water supply for your home. A well-chosen boiler will be a reliable and energy-efficient addition to your household.

Assessing Your Home's Heating Needs

Before purchasing a combi boiler, one must evaluate the heating requirements of their home. Assess factors such as the number of bedrooms and bathrooms, as well as the overall size of the property. For instance, a home with multiple bathrooms may benefit from a combi boiler with a higher capacity to deliver adequate hot water across several outlets simultaneously.

Selecting a Combi Boiler Brand

When it comes to brands, it's advisable to choose a reputable manufacturer that guarantees the reliability and efficiency of their A-rated combi boilers. Brands such as Worcester Bosch and Viessmann are renowned for their high-quality models that promote energy saving without compromising on performance.

Boiler Size and Output Considerations

Determining the correct boiler size and output is essential; too small, and it will struggle to meet demand, too large, and you may face unnecessarily high energy bills. For a smaller home with one bathroom, a compact unit with an output of around 24kW to 30kW is often sufficient. Conversely, larger properties with multiple bathrooms might necessitate a larger boiler with an output upwards of 30kW. When in doubt, consult with a certified heating engineer to identify the ideal model for your specific living situation.

Efficiency and Environmental Considerations

When evaluating combi boilers, homeowners must consider the dual aspects of energy efficiency and the environmental implications of their boiler choice. These considerations influence both running costs and long-term sustainability.

Energy Efficiency and Running Costs

Combi boilers have risen to prominence for their efficient utilisation of energy, which directly correlates to reduced energy bills. Condensing boilers are engineered to capture heat that would otherwise escape through the flue, employing this captured heat to warm up water coming into the system. This process helps achieve an efficiency rating of up to 98%, as seen in the top-tier gas combi boilers in 2023. It's estimated that a highly efficient combi boiler could save homeowners up to £800 annually as opposed to conventional boilers. Models such as the Viessmann Vitodens range exemplify advancements with their impressive efficiency ratings, designed for modern, compact living spaces without compromising on performance.

Environmental Impact of Boiler Types

The type of boiler one chooses impacts their carbon footprint. Considering the global push for sustainability, biomass boilers have gained traction. For instance, the Grant Spira Condensing Wood Pellet Boiler offers an efficiency of up to 93.1%. Although such models require space for fuel storage, they represent a renewable energy option that harnesses biomass, a carbon-neutral fuel source. The environmental return of investing in a biomass boiler comprises reduced carbon emissions and the utilisation of wood pellets, a waste product that would otherwise contribute to landfill.

Maintenance and Aftercare

Proper maintenance ensures that a combi boiler operates efficiently and safely over its lifetime. This section covers the essentials of regular servicing, repair management, and understanding warranty and support provisions.

Regular Servicing

He or she will find that annual servicing is fundamental to the longevity of a combi boiler. A qualified engineer should inspect the system, typically at a cost of £70-£120. This regular check-up not only ensures optimal operation but also upholds manufacturer's warranty requirements. For various boiler types, such as system boilers and heat-only boilers, servicing remains equally crucial for efficient function.

  • System boilers: Expect to pay towards the higher end of the servicing cost spectrum.

  • Heat-only boilers: Although similar, there may be additional considerations for these types, potentially altering the service cost.

Dealing with Repairs

When a combi boiler faces operational issues, it is imperative that repairs are addressed promptly to prevent further damage or safety hazards. Repair costs can vary widely:

  • Minor repairs may be below £100

  • Major fixes, involving part replacements, can exceed £200

A well-maintained boiler, however, will likely encounter fewer repairs over time compared to a neglected system. It is wise to entrust any repair to a Gas Safe registered engineer, who ensures compliance with safety standards and optimal repair quality.

Warranty and Support Services

The intricacies of a combi boiler's warranty can significantly influence future costs. Most boilers come with a manufacturer's warranty, ranging from 1 to 10 years, covering key components and labour. It is critical to understand that regular servicing by a certified professional is often a condition for maintaining the warranty's validity.

Support services offer peace of mind, particularly when they include 24/7 assistance for any boiler-related emergencies that homeowners might not foresee. Many manufacturers and service providers also offer dedicated support lines, providing expert advice to resolve common issues.

  • Manufacturer's Warranty: Up to 10 years, often requiring annual servicing as a condition.

  • 24/7 Support Lines: Immediate assistance for unexpected boiler troubles.

Advanced Considerations for Homeowners

When evaluating the potential of combi boilers for a modern residence, homeowners should give weight to not only the financial aspect but also the technological advancements and sustainability opportunities available.

Innovative Features and Smart Controls

Combination, or 'combi', boilers have evolved significantly, incorporating cutting-edge technology to improve efficiency and user convenience. Modern units come equipped with smart controls that allow homeowners to adjust their heating remotely via an app. This level of control can lead to more efficient energy use and, in turn, lower utility bills. For instance:

  • Programmable Thermostats: Set different temperatures for specific times of the day.

  • Weather Compensation: Adjusts the boiler operation based on the outdoor temperature.

  • Load Compensation: Modifies the heating output based on the difference between the current and desired temperatures inside the home.

Combining Boilers with Renewable Energy Sources

The integration of combi boilers with renewable energy sources is a forward-thinking practice, bridging the gap towards a more sustainable and cost-efficient home heating solution. Solar thermal panels, for example, can preheat water before it enters the combi boiler, reducing gas consumption and utility costs. Furthermore, considering a heat pump as a supplementary heat source can also enhance a home's energy profile. Benefits of pairing renewables with a combi boiler include:

  • Lower Carbon Footprint: Reduces reliance on fossil fuels.

  • Future-Proofing: Prepares for potential new energy regulations.

  • Financial Incentives: May be eligible for government grants or schemes supporting renewables.

By carefully assessing these advanced considerations, homeowners can make an informed decision that aligns with their environmental values and long-term financial planning.

Making the Decision

When selecting a combi boiler for your home, weighing the advantages and understanding the financial considerations is essential. It's important to ascertain whether the benefits meet your specific needs.

Evaluating the Pros and Cons of Combi Boilers

Combi boilers offer hot water on demand, eliminating the necessity for a separate water cylinder, which can be particularly advantageous for smaller properties due to the space savings. The compact nature of these systems makes them suitable for homes where space is at a premium. However, in larger homes with high demand for hot water from multiple outlets simultaneously, a combi boiler may struggle to maintain a consistent supply.

  • Pros

    • Hot water on demand

    • Space-saving

    • Generally lower installation costs

  • Cons

    • May struggle in larger homes

    • High initial demand can impact performance

Calculating Return on Investment

A financial assessment involves considering the upfront combi boiler prices and the potential savings on energy bills. The price of combi boilers typically ranges from £500 to £2,500. Meanwhile, installation costs could add an additional £500 to £1,500 depending on the complexity of the job. Despite these initial expenditures, the return on investment can be significant over time, due to improved energy efficiency and lower operating costs, especially pertinent if replacing an older, less efficient system.

Why Choose a Combi Boiler?

Choosing a combi boiler could be the right decision if a streamlined system offering hot water on demand aligns with your lifestyle and your home's size. These boilers are celebrated for their efficiency and may support the interest in environmentally-conscious living. For those in smaller properties or with less intensive hot water needs, a combi boiler can tick all the right boxes—providing comfortable living conditions and potentially lowering monthly energy costs.

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Frequently Asked Questions

Is it still worth getting a combi boiler?

Yes, a combi boiler remains a worthwhile investment for homes due to its space-saving design and dual functionality, providing both heating and hot water without the need for separate tanks.

What are the disadvantages of a combi boiler?

Combi boilers can struggle in homes with multiple bathrooms as they might not cope with simultaneous demand for hot water. Moreover, they rely on mains water pressure to operate effectively.

How much does it cost to install a new combi boiler in the UK?

The cost to install a new combi boiler in the UK can range from approximately £500 to £2,000. This price varies based on the boiler's size and complexity of installation.

Do I need new pipes for a combi boiler?

If you are upgrading from a conventional boiler system, you might need new pipes to accommodate the higher water pressure that combi boilers require.

Is it cheaper to turn a combi boiler off at night?

Turning a combi boiler off at night can save on energy costs, especially in smaller homes with less hot water use. However, this might not be as cost-effective for larger households.

What is the most economical setting for a combi boiler?

The most economical setting for a combi boiler typically involves balancing a comfortable indoor temperature with the lowest possible thermostat setting, often around 18°C to 21°C.

What temperature should a combi boiler be set at to save money?

To save money, the combi boiler should be set at a temperature that ensures comfort yet is not excessive - usually around 65°C for hot water and between 60°C to 75°C for central heating.

Stephen Day profile photo
Article by
Stephen Day | Co-founder
Gas Safe registered and FGAS certified engineer with over 20 years experience in the heating and cooling industry.