Central Heating Cost Calculator
A full system is the boiler plus everything around it. This prices the lot — radiators, pipework, controls and the flush — rather than just the appliance.
Open the calculator →Price a heating system in 30 seconds
5 steps. Covers boiler type, radiator count, whether pipework is new or existing, controls and region.
How this calculator works
A heating quote is really four numbers: the boiler, the radiators, the pipework and the controls. Radiators are priced here at £260 fitted, the middle of the £150–£400 range, because the spread depends on size and whether the drop already exists. Swapping like-for-like on existing tails is the cheap end; moving a radiator to a new wall, or upsizing it because a room was always cold, adds pipework and making good, so it is worth telling the installer which radiators you actually want changed rather than leaving it as a round number.
Pipework is where quotes diverge most. Reusing sound existing pipe keeps a system change close to a boiler swap; a full first-fix means floors up throughout and is a different job entirely — and the making good afterwards is usually excluded, so ask.
On paperwork: boiler work is notifiable under Building Regulations. Your Gas Safe engineer registers it and you should receive a compliance certificate within about 30 days. Keep it — a conveyancer will ask. One thing that quietly moves the total: a full system upgrade is the moment to fit thermostatic radiator valves and a modern programmable or smart control, because doing it while the system is drained costs a fraction of retrofitting later, and it is what lets a new boiler actually run at its rated efficiency. If you are choosing the boiler itself, our best boiler brands guide weighs reliability and parts backing, and where wet underfloor heating is on the table for part of the house, the underfloor heating cost calculator prices that against radiators.
Central heating installation costs (2026)
| Item | Typical 2026 cost | Notes |
|---|---|---|
| Combi boiler (mid-range) | £1,800–£2,800 | Supplied and fitted |
| System boiler + cylinder | £2,500–£3,800 | For multiple bathrooms |
| Regular (heat-only) boiler | £2,200–£3,500 | Traditional tank layout |
| Radiator, per unit fitted | £150–£400 | Size and drop dependent |
| Pipework, per property | £500–£2,000 | Reuse through to full first-fix |
| Smart thermostat | £150–£300 | Zoning and remote control |
| Thermostatic radiator valves | £15–£35 each | Part L expects these |
| Power flush | £300–£700 | Often a warranty condition |
| Magnetic system filter | £80–£150 | Protects the new boiler |
Figures match our central heating installation guide and include VAT at 20%. Making good floors and decoration after a full first-fix is normally excluded — confirm before you sign.
Central heating calculator FAQs
Three to five days for a whole-house system with new pipework and radiators. A straight boiler swap onto sound existing pipework is one day. The variable is the first-fix: lifting floors throughout adds days and considerable making good afterwards.
On an existing system, usually yes, and many manufacturers make it a warranty condition. Sludge from an old system will foul a new heat exchanger quickly. If the system is genuinely clean a chemical flush may be enough — ask the engineer to justify which they are quoting. Whichever you have, insist the system is dosed with inhibitor afterwards and a magnetic filter fitted on the return, because those two cheap steps are what actually keep a new heat exchanger clean and are the usual condition attached to the longer warranties.
Combi for most 1–2 bathroom homes: no cylinder, no tank, hot water on demand. A system boiler with a cylinder is better where two showers might run at once, or where mains pressure is poor — a combi cannot deliver more than the incoming main gives it. It is worth having the installer check your incoming mains flow rate before deciding, since a combi that looks fine on paper can disappoint in a home with a weak main, and that single measurement settles the combi-versus-system question more reliably than bathroom count alone.
Yes. Boiler work falls under Part L and the flue under Part J. Your Gas Safe engineer notifies it through the Gas Safe building regulations scheme and you should receive a compliance certificate within about 30 days. Ask when to expect it, and chase if it does not arrive.
Related cost guides
- Central heating cost guide — full 2026 pricing
- Boiler replacement calculator — price the boiler on its own
- Heating repair calculator — if it is a fault, not a replacement
- Building regs for boilers — notification and certificates
Get My 3 Free Central Heating Quotes
60 seconds · No spam · No obligation
The calculator’s questions, explained
Each price below is what the calculator above returns when you change only that answer and keep the others at the starting settings (Combi boiler (mid-range), 9 radiators, Partial rework, Add power flush + filter, Midlands): £5,690–£7,586, mid-point £6,540. Figures include the boiler, radiators, pipework, controls and VAT at 20%, as the calculator's result explains; making good floors and decorating after a full first-fix are extra.
Type of boiler
Combi for most homes; system or regular where you need stored hot water for multiple bathrooms. The boiler is the largest single item, and its type decides whether you need a hot water cylinder. Any work on a gas boiler must by law be done by a Gas Safe registered engineer.
| Option | What it means | Estimate | vs starting choice |
|---|---|---|---|
| Combi boiler (mid-range) | No cylinder, heats on demand. Right for most 1–2 bathroom homes. (£1,800–£2,800) Suits most homes with one or two bathrooms: hot water straight from the mains, no tanks or cylinder. It cannot deliver more than the incoming main, so have the flow rate checked first. | £5,690–£7,586 | starting choice |
| System boiler + cylinder | Stored hot water, better for two or more bathrooms used at once. (£2,500–£3,800) For homes where two showers may run at once, or where mains flow is weak. Hot water is stored in a cylinder, which needs cupboard space. | £6,429–£8,572 | +£850 |
| Regular (heat-only) boiler | Traditional layout with tanks. Usually a like-for-like replacement. (£2,200–£3,500) Usually a like-for-like swap in an older home that already has a cylinder and tanks in the loft. Keeping the layout avoids the cost of converting the system. | £6,168–£8,224 | +£550 |
Number of radiators
Count every room. A typical 3-bed semi has 8–10. Each radiator is costed at the same fitted rate, so count the ones being added or replaced. Keeping a sound radiator on its existing pipework lowers a real quote. At the starting settings each extra radiator adds about £260 to the mid-point.
| Size | Typically | Estimate | Mid-point |
|---|---|---|---|
| 6 radiators | £5,011–£6,682 | £5,760 | |
| 8 radiators | £5,464–£7,285 | £6,280 | |
| 10 radiators | £5,916–£7,888 | £6,800 | |
| 14 radiators | £6,821–£9,094 | £7,840 |
Pipework
This is the single biggest variable in a heating install. New runs mean lifting floorboards, and the making good afterwards is usually excluded, so ask what each quote covers.
| Option | What it means | Estimate | vs starting choice |
|---|---|---|---|
| Reuse existing pipework | Boiler swap onto a sound existing system. (£500 typical) For a boiler swap where the radiators stay put and the pipes are sound. A flush still matters, because sludge in old pipes will reach the new boiler. | £5,081–£6,774 | −£700 |
| Partial rework | Some rerouting, new drops to moved radiators. (£800–£1,600) The usual middle case: a few radiators moved or upsized, or new drops where a room was always cold. | £5,690–£7,586 | starting choice |
| Full new pipework | Whole-house first-fix. Floors up, considerable making good. (£1,500–£2,500) For a home with no wet system, failing old pipework or a full renovation. Floors come up throughout, so do it before new flooring and decorating. | £6,386–£8,514 | +£800 |
Controls and system clean
Part L expects proper controls. A flush and a filter protect the new boiler and often the warranty. Under Part L, a replacement boiler needs thermostatic control in each heated room, typically a room thermostat plus radiator valves elsewhere. A new combi in an existing home also needs one extra measure: weather or load compensation, a smart thermostat with automation and optimisation, or flue gas heat recovery.
| Option | What it means | Estimate | vs starting choice |
|---|---|---|---|
| Programmer + TRVs only | Basic controls; Part L may need more. (+£250) The cheapest controls package. Before accepting it, check it includes a room thermostat and, for a combi, one of the Part L extra measures. | £5,298–£7,064 | −£450 |
| Add power flush + filter | Flush the old system and fit a magnetic filter. Often a warranty condition. (+£600–£850) Adds a power flush of the old system and a magnetic filter, which boiler makers often ask for before they give a longer warranty. | £5,690–£7,586 | starting choice |
| Smart controls + flush + filter | Smart thermostat with zoning, plus the flush and filter. (+£850–£1,150) Adds a smart thermostat with zoning. One with automation and optimisation counts as the Part L extra measure for a new combi. | £5,907–£7,876 | +£250 |
Where the property is
Installer day rates vary. London runs about 22% above the Midlands baseline. The region multiplies the whole estimate, by the percentages the calculator shows: London +22% · South East +12% · East of England +8% · South West +4% · Midlands ×1.00 · Scotland −3% · North / Yorkshire −5% · Wales −6%. At the starting settings that moves the mid-point from £6,148 in Wales to £7,979 in London.
Non-price facts above: HSE: gas safety FAQs for home owners; GOV.UK: Approved Document L (conservation of fuel and power).