Getting a new central heating system installed in London is one of the biggest home improvements you will make. A proper system keeps your property warm, cuts energy bills, and adds value to your home. But get it wrong — wrong boiler size, poor pipework, or a cheap installer — and you are looking at years of cold spots, high bills, and expensive repairs.
At imaaplumbing.co.uk, we install central heating systems across every London borough. We have seen every mistake in the book, from undersized boilers in Victorian terraces to botched conversions that left families without hot water for weeks. This guide tells you exactly what a proper central heating installation costs in London, what you should get for your money, and how to avoid the traps that catch most buyers out.
What Central Heating Installation Actually Means
“Central heating installation” covers three different jobs, and the price varies massively between them:
1. New build or first-time installation — No existing boiler, no pipework, no radiators. Full system from scratch.
2. Boiler and pipework replacement — Old system removed, new boiler and pipework installed. Radiators may stay or go.
3. System conversion — Switching from an old back boiler, warm air system, or electric storage heaters to a modern gas combi or system boiler.
Most London homeowners fall into category 2 or 3. A 1930s semi with a 20-year-old boiler and microbore pipework needs a very different job to a new build flat with no heating at all.
Central Heating Installation Cost in London (2026)
London prices run 15–25% higher than the UK average. Parking, congestion charges, access restrictions in period properties, and higher labour rates all push costs up. Here is what you should expect to pay for a complete central heating installation in London:
| Property Type | Bedrooms | System Type | Estimated Cost | Time to Complete |
|---|---|---|---|---|
| 1-bed flat | 1 | Combi boiler + 4 radiators | £3,500–£5,000 | 2–3 days |
| 2-bed terraced | 2 | Combi boiler + 6 radiators | £4,500–£6,500 | 3–4 days |
| 3-bed semi-detached | 3 | Combi boiler + 8 radiators | £5,500–£7,500 | 4–5 days |
| 4-bed detached | 4 | System boiler + 10 radiators + cylinder | £7,000–£10,000 | 5–7 days |
| 5-bed+ large house | 5+ | System boiler + 12+ radiators + cylinder | £9,000–£14,000 | 7–10 days |
These are complete installation prices including boiler, radiators, pipework, controls, labour, certification, and VAT. Prices at the lower end assume straightforward access, standard radiators, and no structural work. Prices at the higher end cover larger properties, smart controls, designer radiators, or complex pipe routing.
What a Proper Central Heating Installation Includes
A complete job is not just swapping a boiler. Here is what a professional central heating installation in London should cover:
- Gas Safe registered engineer — Legally required. Check the number on the official register.
- Boiler unit — Sized correctly for your property (not just what was there before).
- Radiators — Sized using heat loss calculations, not guesswork.
- Pipework — Copper or high-quality plastic (not microbore in most cases).
- Thermostatic radiator valves (TRVs) — Required by building regulations on all radiators except one.
- Programmer/timer and room thermostat — Minimum legal requirement. Smart thermostats are optional upgrades.
- Magnetic filter — Essential for warranty compliance and system longevity.
- Chemical inhibitor — Added to prevent corrosion and sludge.
- Powerflush or system clean — Required for warranty on new boilers.
- Gas Safe certificate — Issued within 48 hours of completion.
- Building control notification — Legally required. Your installer must notify the local authority.
- Warranty registration — 5–12 years depending on brand and installer accreditation.
At imaaplumbing.co.uk, every central heating installation we carry out includes all of the above. No hidden extras. No “that will cost more” surprises on day three.
Combi vs System Boiler: Which One Do You Need?
This is the decision that trips up most buyers. Get it wrong and you either waste money on a boiler that is too big or suffer with not enough hot water.
Combi Boiler — Best For:
- Properties with 1–2 bathrooms
- Homes where space is tight (no cylinder needed)
- Families who do not run multiple showers simultaneously
- Flats and small houses where the boiler can be wall-mounted in a kitchen or cupboard
System Boiler — Best For:
- Properties with 2+ bathrooms used at the same time
- Homes with high hot water demand (large families, power showers)
- Properties with existing cylinder cupboards or space for an unvented cylinder
- Larger houses where a combi cannot deliver enough flow rate
Regular (Heat-Only) Boiler — Best For:
- Properties with traditional open-vented systems and gravity-fed cylinders
- Homes where the existing cylinder and tanks are in good condition
- Situations where you want to replace only the boiler, not the whole system
Most London properties built after 1980 suit a combi boiler. Victorian and Edwardian houses with multiple bathrooms usually need a system boiler with a cylinder. We assess every property individually before recommending.
Radiator Sizing: The Detail Most Installers Skip
A central heating system is only as good as its radiators. Too small and the room never gets warm. Too big and the boiler short-cycles, wasting gas and wearing out faster.
Proper radiator sizing uses heat loss calculations based on:
- Room dimensions (length x width x height)
- Number of external walls and windows
- Insulation levels (cavity wall, loft, double glazing)
- Desired room temperature (21°C for living rooms, 18°C for bedrooms)
Here is a rough guide for standard London properties:
| Room Type | Size | Required Output (BTU/hr) | Typical Radiator Size |
|---|---|---|---|
| Small bedroom | 8–10 m² | 2,500–3,000 | 600 x 600mm single panel |
| Large bedroom | 12–15 m² | 3,500–4,500 | 600 x 1000mm double panel |
| Living room | 15–20 m² | 4,500–6,000 | 600 x 1200mm double panel |
| Kitchen | 10–12 m² | 3,000–4,000 | 600 x 800mm double panel |
| Bathroom | 6–8 m² | 2,000–2,500 | 600 x 600mm towel rail |
These are starting points. A south-facing room with double glazing needs less output. A north-facing room with single glazing and no cavity insulation needs more. At imaaplumbing.co.uk, we calculate every room individually.
Types of Central Heating Systems for London Homes
Wet Central Heating (Gas-Fired) — Most Common
- Gas boiler heats water circulated through radiators
- 85% of UK homes use this system
- Running cost: £800–£1,500 per year for a 3-bed house
- Best for: Properties with a gas connection
Electric Central Heating
- Electric boilers or storage heaters
- No gas connection needed
- Running cost: £1,800–£3,000 per year (2–3x gas)
- Best for: Flats without gas, off-grid properties, future-proofing against gas boiler ban
Air Source Heat Pumps
- Extracts heat from outside air
- 300–400% efficiency (1kW electricity = 3–4kW heat)
- High upfront cost: £8,000–£15,000 installed
- Running cost: Similar to gas with proper insulation
- Best for: Well-insulated new builds, properties with large gardens for outdoor unit
Biomass Boilers
- Burns wood pellets or chips
- High upfront cost, requires fuel storage
- Best for: Rural properties without gas, eco-conscious owners with space
For 90% of London homeowners, a gas-fired wet central heating system remains the best balance of upfront cost, running cost, and reliability. The 2035 gas boiler ban is coming, but hydrogen-ready boilers and hybrid systems will bridge the gap.
Hidden Costs in Central Heating Installation
We have fixed enough botched jobs to know where cowboy installers hide the extras. Here is what to watch for:
1. Gas Pipe Upgrades
Old 15mm gas pipes cannot supply modern boilers. A 22mm or 28mm upgrade costs £200–£500 depending on length and access. This should be identified in the survey, not added on day two.
2. Scaffolding
Properties with boilers on upper floors or external flues may need scaffolding. £300–£600 for a day. Ask upfront.
3. Plastering and Making Good
Removing old pipework leaves channels in walls. Proper making good is £200–£400 per room. Some installers leave this to you.
4. Smart Thermostats
Hive, Nest, or Tado add £200–£400. Basic programmable stats are included in most quotes. Do not let anyone charge £600 for a stat you can buy for £180.
5. Magnetic Filters and Scale Reducers
Non-negotiable for warranty compliance. Should be included. If listed as an extra, question the quote.
6. Parking and Congestion Charges
Central London installations may incur £15–£25 congestion charge and parking fees. A professional installer factors this in upfront.
At imaaplumbing.co.uk, our quotes include everything except structural work. You get a fixed price before we start.
How Long Does Central Heating Installation Take?
| Job Type | Duration | Disruption Level |
|---|---|---|
| Combi swap (existing system) | 1 day | Minimal — water off 4–6 hours |
| Full system in empty property | 2–3 days | Moderate — no heating/water |
| Full replacement (occupied house) | 3–5 days | High — temporary heating needed |
| System conversion (back boiler to combi) | 2–3 days | Moderate — cylinder removal |
| Large property (5+ beds) | 5–7 days | High — phased completion |
We plan every installation to minimise disruption. For occupied properties, we complete heating first so you are not cold overnight. We protect floors, dust-sheet furniture, and clean up before we leave.
Why London Central Heating Costs More Than the Rest of the UK
| Factor | Impact on Cost |
|---|---|
| Congestion charge | £15–£25 per day for central zones |
| Parking restrictions | Meter charges or permit costs |
| Higher labour rates | London engineers earn 20–30% more |
| Access challenges | Narrow Victorian staircases, basement flats, roof spaces |
| Period property restrictions | Listed buildings need consent, specialist flues |
| Material delivery | Traffic delays, restricted delivery windows |
A job that costs £4,500 in Manchester typically costs £5,500–£6,000 in London. The quality of work should be identical. You are paying for location, not better engineering.
Boiler Brands We Recommend for Central Heating Systems
| Brand | Best For | Warranty | Price Range (Installed) |
|---|---|---|---|
| Worcester Bosch | Brand trust, resale value | 5–12 years | £2,000–£3,500 |
| Vaillant | Efficiency, build quality | 5–10 years | £2,200–£3,800 |
| Ideal | Value, parts availability | 5–10 years | £1,800–£3,000 |
| Baxi | Reliability, budget options | 5–7 years | £1,700–£2,800 |
| Viessmann | Long-term efficiency | 5–10 years | £2,500–£4,000 |
| Alpha | Budget installs, 10yr warranty | 10 years | £1,500–£2,500 |
For a complete central heating system, the boiler is 30–40% of the total cost. Spending £300 more on a better boiler is worth it when the total job is £6,000. A 12-year Worcester Bosch warranty versus a 5-year budget brand warranty saves you £2,000+ in replacement costs down the line.
Smart Heating Controls: Worth the Upgrade?
Modern controls can cut heating bills by 20–30%. Here is what is available:
| Control Type | Cost | Savings | Best For |
|---|---|---|---|
| Basic programmer + room stat | Included | 5–10% | Budget installs |
| Programmable TRVs | £150–£300 extra | 10–15% | Zoned control per room |
| Smart thermostat (Hive/Nest) | £200–£400 extra | 15–25% | Tech-savvy households |
| Weather compensation | £300–£500 extra | 20–30% | Maximum efficiency |
| Full zoned smart system | £800–£1,500 extra | 25–35% | Large properties, remote workers |
We recommend at least a smart thermostat for any new installation. The payback is 2–3 years, and the convenience of controlling heating from your phone is genuine.
Central Heating Installation Process: Step by Step
Step 1: Survey and Quote (Day 0) Our engineer visits, measures every room, checks the gas supply, assesses the existing system, and discusses your priorities. You get a fixed written quote within 24 hours.
Step 2: Booking and Materials (Days 1–7) You approve the quote, pay a 25% deposit, and we order materials. Lead time is typically 3–7 days for standard boilers, 2–3 weeks for specialist units.
Step 3: Installation (Days 8–12) Our team arrives, protects your property, removes the old system, installs the new boiler and pipework, fits radiators, and commissions the system. We test every radiator, balance the system, and show you how to use the controls.
Step 4: Certification and Handover (Day 13) We register the warranty, notify building control, issue your Gas Safe certificate, and provide a maintenance schedule. You pay the balance.
Step 5: Aftercare We call after 2 weeks to check everything is working. Annual servicing reminders keep your warranty valid.
Expert Tips for London Homeowners
Tip 1: Do not accept a quote without a site survey. Phone or online quotes for central heating installation are guesses. A proper survey takes 45–60 minutes.
Tip 2: Check your installer’s Gas Safe registration on the official website. The card they show you means nothing. The number on the register is what counts.
Tip 3: Ask for a heat loss calculation, not a “rule of thumb” boiler size. An oversized boiler wastes 15–20% of your gas bill.
Tip 4: Insulate before you install. Cavity wall and loft insulation reduce your heat requirement, letting you fit a smaller boiler and smaller radiators. Saving: £500–£1,000 on the installation, £200+ per year on bills.
Tip 5: Get three quotes, but do not just pick the cheapest. A £4,000 quote that excludes making good, certification, and warranty registration is not cheaper than a £5,500 quote that includes everything.
Common Mistakes When Installing Central Heating
Mistake 1: Keeping old radiators with a new boiler. Old radiators have sludge, corrosion, and reduced output. They strain the new boiler and void the warranty. Replace them.
Mistake 2: Ignoring the cylinder. If you are keeping a hot water cylinder, it must be insulated to modern standards. An uninsulated cylinder wastes £150+ per year.
Mistake 3: Skipping the powerflush. New boilers fail within 2–3 years on dirty systems. The £300 powerflush is cheaper than a £2,000 boiler replacement.
Mistake 4: Using an unregistered installer to save £500. Illegal, dangerous, and uninsured. Your home insurance is void if gas work causes damage.
Mistake 5: Not planning for the future. Hydrogen-ready boilers cost the same as standard units now. Fit one and you are covered for the 2035 gas transition.
Frequently Asked Questions
How much does central heating installation cost in London?
A complete central heating installation in London costs £3,500–£14,000 depending on property size, system type, and complexity. A 2-bed flat with a combi boiler and 4 radiators starts at £3,500. A 4-bed detached house with a system boiler, cylinder, and 10 radiators costs £7,000–£10,000.
Can I get central heating installed in a flat with no gas?
Yes. Electric central heating or air source heat pumps are options. Electric is cheaper to install (£2,500–£4,000) but 2–3x more expensive to run. Heat pumps cost £8,000–£15,000 but qualify for grants and have lower running costs in well-insulated properties.
How long does a full central heating installation take?
2–5 days for most London properties. A 1-bed flat takes 2 days. A 3-bed semi takes 3–4 days. Large houses take 5–7 days. We minimise disruption by completing heating first and protecting your property throughout.
Do I need planning permission for a new boiler?
Not usually. Building regulations approval is required, which your Gas Safe installer handles. Listed buildings and conservation areas may need planning permission for external flues or visible changes.
What is the best boiler for central heating in London?
For most London homes, a Worcester Bosch, Vaillant, or Ideal combi boiler is the best choice. Worcester Bosch leads on brand trust and warranty length. Vaillant offers the best build quality. Ideal provides the best value for money.
Should I replace radiators when installing a new boiler?
Yes, in most cases. Old radiators contain sludge that damages new boilers. Modern radiators are more efficient and come with TRVs as standard. Replacing radiators adds £100–£200 per unit but protects your investment.
Is a combi boiler cheaper to run than a system boiler?
For small to medium homes with 1–2 bathrooms, yes. Combi boilers only heat water when needed, so there is no cylinder heat loss. For larger homes with 2+ bathrooms used simultaneously, a system boiler with a modern cylinder is more efficient.
What grants are available for central heating in London?
The ECO4 scheme provides free or subsidised central heating for low-income households and properties without existing central heating. Eligibility depends on benefits, property EPC rating, and council tax band. We check eligibility as part of our free survey.
Final Word: Invest Once, Invest Right
Central heating installation is not a job you want to do twice. The difference between a £4,000 cowboy job and a £5,500 professional installation is not £1,500. It is the £3,000 you spend fixing leaks, replacing a failed boiler, and re-doing pipework that was never right in the first place.
We have installed central heating in every London borough, from basement flats in Kensington to 5-bed houses in Bromley. Our quotes are fixed, our engineers are Gas Safe registered, and our work is guaranteed.
If you want a central heating system that works properly from day one, get your free fixed-price survey at imaaplumbing.co.uk. We answer the phone, we show up on time, and we do not leave until the job is done right.
