Boilers & Central Heating: Costs, Repairs & Quotes
A combi swap runs £1,900–£3,800 fitted, a system boiler £2,800–£4,800, and a full central heating install £3,000–£8,000. Those are ranges because the boiler you pick, your pipework and your region each move the number by hundreds. Choose your job below for the full breakdown — or tell us what you need and get three itemised quotes from local heating engineers near you.
What do you need doing?
Each job has its own page with the full 2026 price ranges, what moves the number, and a quote form matched to that exact trade — so your enquiry reaches the right specialist.
Boiler installation costs at a glance — 2026
Typical fitted prices and common extras, from this page.
Source: BestBuilders 2026 quote data · 519 UK towns
These are ranges, not prices — your boiler choice, pipework and region set the real number. Get my exact price →
Boiler Installation for Every Home
From a straight combi swap in a flat to a full system boiler with a new cylinder or a conversion — vetted engineers for every job.
Swapping an old combi for a new one in the same spot. Usually a one-day job. The most common and affordable upgrade, with a new flue, filter and controls included.
Get quotes →A system or conventional (heat-only) boiler feeding a hot-water cylinder, suited to larger homes and multiple bathrooms. Allow one to two days plus a new or upgraded cylinder.
Get quotes →Converting between boiler types or moving the boiler to a new location. The most involved job, with extra pipework, condensate routing and making good. Allow two to three days.
Get quotes →Boiler Installation Cost Drivers
| Cost driver | Typical effect | When it applies |
|---|---|---|
| Boiler type | Main price factor | Combi, system or conventional — and whether you change type |
| Brand & warranty | +£200 – £900 | Premium brands and longer guarantees cost more upfront |
| Cylinder & pipework | +£400 – £1,500 | New cylinder, moved pipes or upsized gas supply |
| Powerflush / filter | +£300 – £700 | Recommended on older systems; a magnetic filter protects the new boiler |
| Relocation & flue | Varies | Moving the boiler or re-routing the flue adds labour and materials |
A like-for-like combi swap usually sits inside the £2,200–£3,500 range. London and the South East run higher than the national average. A full boiler cost breakdown is in our cost guide.
3 Steps to a Boiler Quote
Tell us about your boiler
60-second form. Your current boiler type, the number of bathrooms, where it lives and any faults. No phone, no jargon.
Get matched to engineers
Up to 3 vetted heating engineers near you. We pre-screen on registration and reviews.
Compare & book
Itemised quotes within 24 hours. Compare the boiler brand, warranty length, filter and flush before you book.
What a Boiler Installation Includes (2026)
A boiler installation is more than the appliance itself. Knowing what is included helps you compare quotes fairly.
🔥 The boiler & flue
The new combi, system or conventional boiler plus a new flue, fitted and commissioned to the manufacturer’s instructions so your warranty stays valid.
📜 Building Regs notification
Every gas boiler installation must be notified to Building Control. Your Gas Safe registered engineer self-certifies this and you receive a compliance certificate — keep it with your warranty.
🧲 Magnetic filter & powerflush
A system flush (or powerflush on older systems) clears sludge, and a magnetic filter is fitted to protect the new boiler. Many warranties require both.
🌡️ Controls & thermostat
A modern programmable or smart thermostat and TRVs help you control heating room by room and meet efficiency requirements.
💧 Cylinder (if needed)
System and conventional boilers feed a hot-water cylinder. A new or upsized cylinder may be fitted for larger homes or extra bathrooms.
🛡️ Warranty & registration
The engineer registers the boiler with the manufacturer so the guarantee (often 7–12 years on premium brands) is valid from day one.
Boiler Grants & the Warm Homes Scheme
Some households can get help towards a new heating system. Here is what is available in 2026 and how to check eligibility.
💷 Boiler Upgrade Scheme
The Boiler Upgrade Scheme (BUS) offers grants towards heat pumps rather than gas boilers. If you are open to a low-carbon system, your installer can explain whether it suits your home. See our step-by-step guide to claiming a Boiler Upgrade Scheme grant.
🏠 Warm Homes & ECO4
The Warm Homes scheme and ECO4 can help lower-income or off-gas households replace an inefficient boiler. Your installer can tell you whether your home and income qualify before you commit.
📊 Should you repair or replace?
If your boiler is over 10–12 years old, breaking down repeatedly or costly to run, replacement usually pays back through lower bills and a long warranty. A survey gives you a clear answer.
⚡ Combi vs system vs heat-only
The right boiler depends on your home size, water pressure and number of bathrooms. Our comparison of boiler types explains which suits you.
What’s in a boiler price — and what isn’t
The boiler itself is usually only about a third of the bill. Most of the difference between two quotes for the same model sits in the work around it — the flush, the controls, the gas run and whether the boiler is moving position. Ask for it itemised.
| Line item | Typical 2026 cost | Usually included? |
|---|---|---|
| The boiler unit | £700–£1,600 (combi) | Yes — check the exact make, model and output |
| Labour, 1–2 days | £600–£1,200 | Yes |
| Removing and disposing of the old boiler | Included in most quotes | Usually — confirm in writing |
| System flush | £150–£300 (chemical) / £300–£600 (power flush) | Often separate — and often a warranty condition |
| Magnetic system filter | £120–£200 | Frequently required for the warranty — check |
| Gas supply upgrade to 22mm | £150–£400 | No — only known once the engineer surveys |
| Flue extension or repositioning | £100–£300 | No |
| Moving the boiler to a new position | £400–£1,000 | No — new gas, water, flue and condensate runs |
| Conventional to combi conversion | £500–£1,500 on top | No — includes removing tanks and cylinder |
| Smart or programmable controls | £150–£350 | Varies — but Part L requires proper controls |
| VAT | 20% on a gas boiler replacement | Check whether the quote is inclusive |
The two variations that most often move the final figure are a gas run that turns out to be too narrow for the new appliance, and a system that needs a power flush rather than a chemical one. Ask the engineer to price both scenarios at the survey rather than discovering them on the day. For prices by boiler type see the boiler cost calculator.
How long a boiler installation takes
Most straight swaps are a one-day job. You will be without heating and hot water for that day, so if anyone in the house needs continuous heating, say so when you book — a good engineer will plan around it.
| Job | On-site time | Notes |
|---|---|---|
| Combi swap, same position, same make | 1 day | The most common job; water back on the same evening |
| Combi swap plus power flush | 1–2 days | The flush is what adds the time, not the boiler |
| New system boiler and cylinder | 2–3 days | Cylinder position and pipework drive the difference |
| Conventional to combi conversion | 2–3 days | Tanks and cylinder come out; loft pipework is capped |
| Moving the boiler to another room | +1 day | New gas, water, flue and condensate routes |
| Full central heating installation | 3–5 days | Pipework and radiators throughout the property |
Your Building Regulations compliance certificate is issued after the work, not on the day — typically within about 30 days. Ask when you should expect it and chase if it does not arrive; you will need it when you sell.
How long a boiler lasts
A modern condensing boiler is a shorter-lived appliance than the cast-iron units it replaced. Efficiency also drifts down over time, so the economics of repairing an older boiler get worse each year even when it is still running.
| Component | Expected life | What usually fails first |
|---|---|---|
| Combi boiler | 10–15 years | Diverter valve, then the PCB |
| System or regular boiler | 12–18 years | Pump and expansion vessel |
| Hot water cylinder | 15–25 years | Immersion element and coil scaling |
| Radiators | 15–25 years | Internal corrosion where the system was never inhibited |
| Manufacturer warranty | 5–12 years | Voided by a missed annual service more often than by a fault |
Two rules of thumb. Once a boiler is past 10 and needs a repair over roughly £500, put that money toward a replacement instead. And whatever the warranty length, it almost always depends on an annual service and, on many brands, a magnetic filter being fitted at installation — so both belong in the original quote.
Building regulations and gas safety for boiler work
Gas work is legally restricted. Under the Gas Safety (Installation and Use) Regulations, only a Gas Safe registered engineer may work on your gas appliances. This is not a quality badge, it is the law — and it is on you to check, because we do not check it for you. Ask to see the engineer’s Gas Safe ID card, then verify the licence number on the Gas Safe Register itself. The card shows which appliance categories they are qualified for, so check that it actually covers boilers.
Building regulations — yes, always. Replacing a boiler is notifiable work under Part L, and the flue and ventilation fall under Part J. Your engineer notifies it through the Gas Safe building regulations scheme and you should receive a Building Regulations Compliance Certificate, usually within about 30 days. Keep it: a conveyancer will ask for it, and getting a retrospective certificate later is slow and costs more.
Planning permission — normally not. A boiler replacement inside the property does not need it. You may need consent if the building is listed or in a conservation area, or where a new flue terminal would be on a wall or roof slope facing a highway. Part L also expects the system to end up with proper controls — typically a programmer, a room thermostat and thermostatic radiator valves — so if a quote leaves those out, ask why.
Before you let anyone start
- See the Gas Safe ID card, then check the number on the register — not just the card
- Confirm the card covers the appliance type being fitted
- Get the quote itemised: make, model, flush type, filter, controls, warranty length
- Ask who notifies building control and when your certificate arrives
- Ask what the warranty requires of you each year
- Never pay the full amount before the work is done
Related: planning rules for plumbing work.
How to check a heating engineer before you commit
Gas work is legally restricted to Gas Safe registered engineers, and we do not check that for you — so this is the one trade where verifying the person is not optional. It takes two minutes.
Check the register, not the card
Ask for the Gas Safe ID card, then type the licence number into the Gas Safe Register yourself. Cards expire and can be borrowed. Check the back too — it lists which appliance types they are actually qualified for.
Get the quote itemised
Make, model and output of the boiler; whether the system is chemically flushed or power flushed; whether a magnetic filter is included; what controls you get; and the warranty length that specification earns.
Confirm the paperwork route
Ask who notifies building control and when your Building Regulations compliance certificate will arrive. If nobody can answer that, the job is not being registered — and you find out when you sell.
On payment: a deposit against the boiler is normal; the balance is due on completion and commissioning, not before. Pressure to pay in full, in cash, on the day is the clearest warning sign in this trade.
Boiler Installers by Town
Vetted boiler installers across UK towns:
Boiler Installation FAQs
Question this page didn't answer?
Ask a specific question about your boiler project. A member of our editorial team will answer and publish it (your email is never shown).
Boiler Installation Guides & Costs
Planning a new boiler? These guides explain costs, grants and how to choose the right boiler type.
Boiler Replacement Cost (2026)
A full breakdown of new boiler costs by type, brand and job complexity, with money-saving tips.
Read more →How Much Does a New Boiler Cost?
Real 2026 UK price ranges for combi, system and conventional boilers, plus what drives the final figure.
Read more →Combi vs System vs Heat-Only
Compare the three boiler types side by side to find the right one for your home and water use.
Read more →Claim a Boiler Upgrade Scheme Grant
A step-by-step guide to the Boiler Upgrade Scheme and other 2026 heating grants.
Read more →Looking for local quotes? Find vetted trades in your town →
Complete your project
Homeowners planning boiler installation often line up these trades too — get free, no-obligation quotes in the same few clicks.
Are you a heating engineer? List your business on BestBuilders and receive local boiler enquiries.
Our sources for this guide
Cost ranges, grant eligibility and regulatory information on this page are compiled from:
- Best Builders 2026 Cost Index — regional boiler and central heating cost ranges aggregated from active quote requests across 519 UK towns, refreshed quarterly
- Gas Safe Register — the legal register for gas work in the UK; who may install and commission a gas boiler
- GOV.UK — Boiler Upgrade Scheme — grant values and eligibility for heat pump replacements
- Ofgem — Energy Company Obligation (ECO4) — the scheme behind Warm Homes boiler help
- UK Building Regulations Approved Document J — combustion appliances, flues and ventilation
- UK Building Regulations Approved Document L — boiler efficiency and heating controls requirements
- Energy Saving Trust — running-cost and efficiency comparisons between heating systems
Editorial standards & how to reach us
Are you a heating engineer? List your business on BestBuilders and receive local boiler enquiries.
This page is maintained by the Best Builders editorial team. Cost figures are reviewed quarterly against active UK boiler quote data. Regulatory information (Building Regs, gas safety, grant schemes) is checked against current UK government guidance at each refresh. We do not accept payment for editorial coverage; heating engineer listings are earned through our vetting process.
If you spot an error or have feedback, email editorial@bestbuilders.co.uk.
Last updated: 17 June 2026 · Next scheduled review: October 2026