Replacing a boiler is one of the most significant home improvement costs a UK homeowner will face. With energy prices remaining elevated and government incentives available for heat pumps, understanding the true cost of replacement has never been more important. This guide provides up-to-date 2026 cost data based on real installer quotes across the UK.
The total cost of a boiler replacement includes the unit itself, labour (typically 1-2 days for a like-for-like swap), removal and disposal of the old boiler, new controls (a smart thermostat is legally required under Boiler Plus regulations), and any additional pipework or flue modifications needed.
| Boiler Type | Budget | Mid-Range | Premium | Includes Labour |
|---|---|---|---|---|
| Combi Gas Boiler | £1,800 | £2,500 | £3,500 | Yes |
| System Gas Boiler | £2,000 | £3,000 | £4,000 | Yes |
| Regular (Heat Only) Gas | £2,200 | £3,200 | £4,500 | Yes |
| Oil Boiler | £2,500 | £3,500 | £5,000 | Yes |
| Air Source Heat Pump | £7,000 | £10,000 | £15,000 | Yes (less £7,500 grant) |
| Brand | Reliability Score | Warranty | Best Model | Price Range |
|---|---|---|---|---|
| Worcester Bosch | 94% | Up to 10 years | Greenstar 4000 | £900-£1,800 unit |
| Vaillant | 92% | Up to 10 years | ecoTEC Plus | £850-£1,700 unit |
| Ideal | 89% | Up to 7 years | Logic Max | £650-£1,200 unit |
| Baxi | 87% | Up to 7 years | 800 Series | £600-£1,100 unit |
| Viessmann | 91% | Up to 10 years | Vitodens 100 | £1,000-£2,000 unit |
The Boiler Upgrade Scheme provides a £7,500 grant for homeowners in England and Wales installing an air source heat pump. The grant is applied directly by your MCS-certified installer, so you never see the full cost. To qualify, your home must have a valid Energy Performance Certificate (EPC) with no outstanding recommendations for loft or cavity wall insulation.
Ground source heat pumps also qualify for a £7,500 BUS grant. The scheme runs until March 2028 and is available on a first-come, first-served basis through your installer who claims the voucher on your behalf.
Upgrading from an old G-rated boiler (50-70% efficiency) to a modern A-rated condensing boiler (92%+ efficiency) can generate substantial annual savings. For a typical 3-bedroom semi-detached home in the UK, the expected savings are approximately £580 per year on gas bills. Larger detached homes may save £700-£900 per year.
Heat pumps, while more expensive to install, operate at 300-400% efficiency (measured as Coefficient of Performance). This means for every unit of electricity consumed, 3-4 units of heat are produced. However, as electricity costs more per kWh than gas, actual running cost savings depend heavily on your property's insulation level.
Many UK homeowners spread the cost of a new boiler through finance. British Gas, OVO Energy, EDF, and independent installers offer 0% finance over 12-72 months for qualifying customers. A typical £2,500 combi boiler installation paid over 24 months at 0% would cost around £104 per month.
The ECO4 scheme and the Great British Insulation Scheme may also fund boiler replacements for low-income households or those on qualifying benefits. Contact your local council or energy provider to check eligibility.
Use the following rules of thumb to decide whether repair or replacement makes more financial sense:
Since April 2018, all new gas boiler installations in England must comply with Boiler Plus regulations. This requires: a minimum ErP A-rated boiler, time and temperature zone controls (smart thermostat), and for combi boilers, at least one additional energy-efficiency measure such as flue gas heat recovery or load compensation. Failure to comply can affect your home insurance and future property sale.
A new combi boiler costs between £1,800 and £3,500 fully installed in 2026, including labour, parts, and a smart thermostat (required under Boiler Plus regulations). The price varies by brand, property size, and complexity of the installation. Worcester Bosch and Vaillant tend to be at the higher end, while Ideal and Baxi offer more budget-friendly options with slightly shorter warranties.
The Boiler Upgrade Scheme (BUS) offers a £7,500 grant towards the cost of installing an air source heat pump or ground source heat pump in England and Wales. The grant is applied at point of sale by your MCS-certified installer, reducing your upfront cost significantly. Your home needs a valid EPC with no outstanding cavity wall or loft insulation recommendations to qualify.
Replacing a G-rated boiler with a new A-rated condensing boiler can save approximately £580 per year on energy bills for a semi-detached home. Larger homes may save £700-£900 annually. The savings come from improved efficiency - modern boilers extract 92%+ of heat from the fuel, versus 50-70% for old G-rated models. Your payback period on a £2,500 installation would typically be 4-5 years from energy savings alone.
If your boiler is over 10-12 years old and repair costs exceed £500, replacement is usually more cost-effective. Boilers older than 15 years are significantly less efficient. Use the 50% rule: if a repair costs more than 50% of what a new boiler would cost, replacement is the better financial decision. Factor in that a new boiler will also lower your annual running costs and comes with a warranty of 5-10 years.
Yes. Under the Boiler Plus regulations (effective since April 2018 in England), all new gas boiler installations must include a time and temperature zone control - in practice, a smart thermostat. This is a legal requirement, not optional. Smart thermostats from brands like Nest, Hive, or tado can save an additional £75-£150 per year through better scheduling, so they pay for themselves quickly.
Worcester Bosch and Vaillant consistently top UK reliability surveys. Worcester Bosch scores around 94% customer satisfaction, followed by Vaillant at 92%, Viessmann at 91%, Ideal at 89%, and Baxi at 87%. All come with 5-10 year warranties depending on the model and whether installation is completed by an accredited installer. Worcester Bosch installers can offer warranties up to 10 years on selected models.
Yes, many installers and energy companies including British Gas, OVO Energy, and EDF offer 0% finance options for new boiler installations. Terms typically range from 12 to 72 months. A £2,500 boiler over 24 months at 0% would cost around £104 per month. These offers typically require a credit check and UK residency. Low-income households may also qualify for free boiler replacement through the ECO4 government scheme.