The installation of boiler equipment is a key investment in your home’s comfort, energy efficiency, and long-term value. Whether you’re replacing a faulty unit, upgrading to a modern high-efficiency system, or switching boiler types altogether, understanding the process is vital. With numerous options available and various regulations to comply with, it’s important to make informed decisions. At Heroes on Hand, we guide homeowners through every stage—from selecting the right boiler to the final handover. This article explores the most common boiler types, the step-by-step installation process, what to expect, and essential considerations such as cost, regulations, and boiler placement.
Before diving into the boiler installation process, it’s crucial to know the different types of boilers commonly used in UK homes. Each type has its own benefits and is suited to different household needs.
Combi boilers, short for combination boilers, are one of the most popular choices among UK homeowners. These systems provide both heating and hot water directly from the boiler unit, eliminating the need for a separate hot water cylinder or cold water tank. Compact in design and highly efficient, combi boilers are ideal for smaller homes or flats with limited space. Because they heat water on demand, there’s no waiting time for hot water, and you don’t lose energy keeping a tank warm. However, they can struggle to supply water to multiple taps or showers simultaneously, making them less suitable for larger households with high water demand.
System boilers use a separate hot water cylinder but, unlike conventional systems, draw water directly from the mains supply. This means they can supply multiple taps at once without pressure loss. System boilers are well-suited for larger homes and growing families that require a consistent supply of hot water. They’re also a good match for solar thermal systems, as the cylinder can be integrated with renewable energy sources. They do require additional space for the cylinder, typically located in an airing cupboard, but don’t need a cold water tank in the loft.
Conventional boilers, also referred to as regular or heat-only boilers, are most often found in older homes with traditional heating setups. These systems use both a hot water cylinder and cold water storage tanks, typically installed in the loft. They are a reliable option for homes with low water pressure or multiple bathrooms where hot water demand is high at the same time. However, conventional boilers take up the most space and are gradually being phased out in favour of more efficient alternatives.
The installation of boiler systems is a structured and highly technical process that must always be carried out by a qualified, Gas Safe registered engineer. Here’s what you can expect when having a boiler installed in your home.
The process begins with a professional engineer visiting your home to evaluate your current heating setup. This includes inspecting your existing boiler (if any), checking the pipework and flue positions, and understanding your household’s hot water needs. At Heroes on Hand, we always recommend a physical site visit over an online survey, as it gives a clearer view of the property’s layout, access points, and any potential challenges. The engineer also checks for compatibility issues between your existing system and the new boiler, which could influence installation complexity or cost.
Once the assessment is complete, you’ll receive a detailed quotation. This includes the recommended boiler model, an outline of the installation plan, and information about any additional work that may be required—such as replacing radiators or upgrading pipework. This step ensures transparency and allows you to make an informed decision before proceeding.
On the day of installation, the first task is safely removing the old boiler. The engineer disconnects it from the gas, water, and electrical supply before carefully removing it from your property. The old unit is then disposed of in line with environmental regulations.
Once the old boiler has been removed, the engineer prepares the site for the new installation. This may involve modifying existing pipework, preparing or strengthening the mounting area, and ensuring there’s appropriate space for flues or a condensate pipe (especially important for modern condensing boilers). Safety compliance is paramount here—ventilation, structural support, and fire safety checks are all part of this step.
The new boiler is then installed according to the manufacturer’s specifications. The engineer mounts the unit securely and connects it to gas, water, and electrical systems. All necessary components—such as flues, vents, thermostats, and any smart controls—are fitted during this stage.
Once the installation is complete, the entire system undergoes rigorous testing. The engineer checks water pressure, heating output, and control functionality. They perform a combustion analysis to ensure the boiler is running efficiently and verify that all safety features are working as intended. A hydrostatic test is often carried out to confirm the integrity of the pipework and the entire heating system.
The final stage is the handover. The engineer explains how to use your new boiler, covering basic operation, controls, and energy-saving tips. They’ll also provide warranty documentation, register your boiler with the manufacturer, and notify the local authority to ensure compliance with building regulations.
The location of your boiler significantly impacts its accessibility, noise levels, safety, and efficiency. In many UK homes, the kitchen is the most common site for boiler installation. Combi boilers in particular are often installed inside kitchen cupboards to save space and for convenient access to water and gas supplies.
If space is available, a utility room is an excellent choice. It keeps the boiler separate from living spaces, reducing noise and visual impact. This location is particularly popular for larger system or conventional boilers, which need more room.
Some homeowners choose to install boilers in bathrooms, especially when space elsewhere is limited. While this is possible, extra precautions must be taken to protect the boiler from humidity and to ensure compliance with electrical safety regulations.
Bedrooms are less common but can work if the boiler is very quiet and sealed within a cupboard. A carbon monoxide detector is essential in this case.
Finally, some households opt for loft installations, particularly when internal space is at a premium. While this keeps the boiler out of the way, it requires proper insulation and a fixed ladder for safe access during servicing. Regardless of location, UK regulations require sufficient clearance around the boiler for servicing (usually 600mm at the front), structural support for the unit, and external flue access through a wall or roof.
Installing a boiler in the UK involves several legal and safety requirements. It is a legal requirement for all gas boiler installations to be carried out by a Gas Safe registered engineer. For oil boilers, installers must be registered with an approved Competent Person Scheme such as OFTEC.
Building regulations also dictate standards for flue positioning, ventilation, system performance, and energy efficiency. The installation must comply with Approved Document J, which covers flue systems, hearths, and combustion air supplies. Additionally, boilers installed in domestic settings must meet the Boiler Plus legislation, requiring a minimum energy efficiency rating of 92% (ErP A-rated).
Once installed, your boiler must be registered with your local authority within 30 days. A commissioning certificate, such as the Benchmark certificate, is also required to validate the installation. Failing to meet these obligations can void warranties, affect home insurance, and lead to legal penalties.
Recent updates to building regulations also require installations to follow BS 7593:2019, which includes water treatment, use of magnetic filters to prevent sludge build-up, and proper system cleansing. These practices are essential for preserving the lifespan of your boiler and ensuring optimal performance.
The cost of a boiler installation can vary depending on the type of boiler, the complexity of the installation, and the condition of existing heating infrastructure. As of 2025, replacing a combi boiler with another combi boiler typically costs between £1,600 and £3,200, including labour. Switching from a conventional system to a combi involves more work—such as removing tanks and redirecting pipework—and may cost between £2,800 and £4,000.
Removing a back boiler hidden behind a fireplace can be one of the most expensive tasks, often ranging from £3,000 to £4,500. A completely new installation, including boiler and basic pipework, may start at £1,600 but can increase significantly depending on access and additional work needed.
Boiler prices themselves vary: combi boilers range from £600 to £4,000, system boilers from £600 to £3,000, and conventional boilers from £600 to £3,500. Labour, new controls, thermostats, or smart systems may add an additional £1,000 to £2,000 to the total.
Although the upfront cost can be substantial, the savings over time are equally noteworthy. A new, energy-efficient boiler can save up to £580 per year on energy bills, meaning the investment often pays for itself within just a few years.
An often overlooked aspect of the installation of boiler systems is the compatibility with your existing infrastructure. Older homes may have outdated pipework or radiators that limit efficiency or place strain on new boilers. If your pipework is narrow, corroded, or noisy, it may need replacing to support a modern system. Likewise, ageing radiators can develop cold spots and uneven heat distribution, affecting overall system performance.
While replacing pipework or radiators increases initial costs, it enhances performance, lowers maintenance needs, and ensures better compatibility with smart controls and energy-saving features.
Keeping your new boiler in top condition also means maintaining your warranty. Most manufacturers require annual servicing by a qualified engineer, use of genuine parts for repairs, and registration of the boiler within 30 days of installation. Failing to meet these conditions could result in the warranty being voided, leaving you liable for costly repairs.
The installation of boiler systems is not just a technical upgrade—it’s a major investment in your home’s future. From choosing the right type to ensuring regulatory compliance and proper maintenance, the process involves several important decisions. By understanding the installation process and considering key factors like location, cost, and compatibility, homeowners can make confident and informed choices.
At Heroes on Hand, we’re committed to making boiler installation simple, safe, and cost-effective for London households. Whether you’re upgrading an old unit or installing a new system for the first time, our Gas Safe registered engineers are here to help—from the first survey to final commissioning and beyond.
If you’re planning to upgrade your boiler, contact Heroes on Hand today to schedule your professional assessment and discover the best heating solution for your home.
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