Boiler Installation Cost
£2,000–£4,500
typical UK range
Updated
A new boiler installation in the UK costs between £2,000 and £4,500 for a standard combi boiler swap, rising to £5,000+ for system or regular boilers, or where significant additional work is required. The boiler itself typically costs £700–£2,000; labour accounts for the remainder.
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How much does each option cost?
| Type / scope | Typical cost | Notes |
|---|---|---|
| Standard combi boiler swap (like-for-like location)Straightforward replacement of an existing combi boiler with a new model in the same location — the most common installation type | £1,800–£3,200 | Straightforward replacement of an existing combi boiler with a new model in the same location — the most common installation type |
| Combi boiler with flue extension or relocationAdditional pipework or flue work required; adds 2–4 hours to the standard installation time | £2,200–£3,800 | Additional pipework or flue work required; adds 2–4 hours to the standard installation time |
| System boiler installationSystem boilers require a separate hot water cylinder; includes cylinder installation | £2,500–£4,500 | System boilers require a separate hot water cylinder; includes cylinder installation |
| Regular (heat-only) boiler installationRequires separate hot water cylinder and cold water tank; more complex installation | £2,800–£5,000 | Requires separate hot water cylinder and cold water tank; more complex installation |
| Conversion from regular to combiRemoving the old cylinder and tank, adjusting pipework layout, and installing the combi — a full-day job minimum | £3,000–£5,500 | Removing the old cylinder and tank, adjusting pipework layout, and installing the combi — a full-day job minimum |
| New central heating system with boilerInstalling radiators, pipework, controls, and boiler from scratch in a property without existing central heating | £4,000–£8,000 | Installing radiators, pipework, controls, and boiler from scratch in a property without existing central heating |
| Smart controls and thermostat upgradeSmart thermostats (Nest, Hive, Tado) installed alongside the new boiler; often added to the installation quote | £150–£400 | Smart thermostats (Nest, Hive, Tado) installed alongside the new boiler; often added to the installation quote |
What affects the price?
- Boiler make and model — budget combi boilers (e.g. Baxi, Ideal) start from £500–£700; mid-range (Worcester Bosch, Vaillant) cost £800–£1,200; premium (Viessmann, Buderus) cost £1,200–£2,000+
- Existing system type — swapping like-for-like is cheapest; conversions from regular to combi or system require significantly more work
- Flue routing — standard rear or side flue through an external wall is simplest; long flue runs, vertical flues, or flues through multiple floors add cost
- Location of boiler — an accessible boiler cupboard is cheapest; awkward locations (loft, under stairs, tight utility room) add time and cost
- Condition of existing pipework — if the existing pipework is corroded, undersized, or needs significant modification, costs increase
- Power flushing requirement — boilers installed in older systems often require a power flush to remove sludge and scale before installation; costs £200–£400 but protects the new boiler
- Controls and smart thermostat — a basic programmable thermostat is often included; smart controls (Nest, Hive) are optional extras
- Location in the UK — London and South East prices are typically 20–30% higher than the national average
What's included in the price?
- Removal and disposal of the old boiler (and cylinder/tank if applicable for conversion jobs)
- Supply and installation of the new boiler
- Connection to existing gas and water supply
- Installation of a new flue (or reuse of existing if suitable)
- Fitting of controls and programmer
- System flush (power flush or chemical flush) to protect the new boiler
- Commissioning and testing in accordance with manufacturer requirements
- Gas Safety Certificate (CP12) — provided by the Gas Safe registered engineer
- Manufacturer warranty registration
- Building Regulations compliance notification where required
How long does it take?
A straightforward combi boiler swap takes 1–1.5 days for an experienced Gas Safe engineer. Conversions from regular to combi, or installations requiring significant pipework work, typically take 2–3 days. Full central heating installations with a new boiler can take 3–5 days or more depending on the property size. You will be without heating and hot water during the installation, so plan accordingly — particularly in winter.
Do I need one?
Boilers typically have a functional lifespan of 10–15 years. Signs it's time to replace rather than repair: the boiler is more than 12 years old and has recurring faults; repair costs exceed 50% of a new boiler price; the boiler operates at significantly below design efficiency (modern A-rated boilers are over 90% efficient; old G-rated boilers may be 65–70%); spare parts are no longer available. All gas boiler work must be carried out by a Gas Safe registered engineer — this is a legal requirement. A new boiler must be installed to Building Regulations standards and certified.
How do you avoid overpaying?
- Get 3 quotes from Gas Safe registered engineers — prices vary by £300–£800 for the same job. Always verify Gas Safe registration at gassaferegister.co.uk
- Consider mid-range boilers (Worcester Bosch 4000, Vaillant ecoFIT) rather than premium models — the reliability difference is modest and the cost saving can be £400–£800
- Book in winter or early spring when engineers are between peak seasons; some offer modest off-peak discounts
- Ask whether power flushing is genuinely necessary — on newer systems (under 7 years old) with clean water, a chemical inhibitor may be sufficient
- Consider keeping your existing controls/thermostat if they're relatively new and compatible with the new boiler
- Ask about the boiler warranty — some manufacturers offer extended warranties (up to 12 years) on mid-range models when registered online. A long warranty can offset a higher boiler cost
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Frequently asked questions
We’re happy to answer all your questions.
How much does a new boiler cost including installation in the UK?
A complete new combi boiler supply and installation in the UK costs £1,800–£3,200 for a standard like-for-like swap, rising to £4,000–£5,500 for conversions from regular to combi boiler. The boiler itself accounts for £600–£1,800 of the total; labour for the remainder. London and South East prices are typically 20–30% higher.
How long does a new boiler installation take?
A straightforward combi boiler swap takes 1–1.5 days. Conversions from regular to combi typically take 2–3 days. Larger jobs involving significant pipework changes or new heating systems can take 3–5 days. You'll be without heating and hot water during installation.
What is the best boiler for a UK home?
Worcester Bosch and Vaillant are consistently rated the most reliable boiler brands in the UK. For most homes, a combi boiler (no separate cylinder) is the simplest and most efficient choice. System boilers are better for homes with high hot water demand (3+ bathrooms). Boiler type depends on your hot water usage and existing heating system.
Do I need a Gas Safety Certificate when fitting a new boiler?
Yes. Any Gas Safe registered engineer installing a new boiler must complete a Gas Safety Certificate (CP12) documenting the installation. The installation must also be notified to Building Control under Part J of the Building Regulations, or self-certified by a competent person registered under an approved scheme — your Gas Safe engineer handles this.
Is it worth getting a new boiler or repairing the old one?
If your boiler is over 10 years old and requires a repair costing more than £300–£400, replacement is usually more cost-effective. Modern A-rated boilers are 90%+ efficient, typically saving £150–£300/year on energy bills compared to older G-rated models. For boilers under 5 years old with a current warranty, repair is usually preferable.
Boiler Installation Cost in your city
Prices vary with local labour rates — see the typical range where you are.
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