LPG (liquefied petroleum gas, primarily propane) is the main alternative to oil heating for UK homes off the gas grid. Around 4 million UK homes have no mains gas connection, and LPG is the closest like-for-like replacement in terms of comfort, system design, and how it integrates with existing radiators and hot water systems.

This guide sets out what a conversion costs in 2026, what drives the price, and how LPG compares with the alternatives on running costs.

What Does an LPG Conversion Involve?

If you’re switching from oil, the boiler itself is likely the main change, both oil and LPG systems use a wet central heating circuit (radiators, pump, expansion vessel) and hot water cylinder. The pipe configuration can often be reused or adapted with minimal replumbing.

If you’re converting from electric storage heaters or a coal system, the job is larger: full radiator installation, pipework throughout the house, a new boiler, and tank installation. This is a full central heating installation, not a simple boiler swap.

A typical LPG conversion involves:

  1. A new LPG-specific condensing boiler
  2. An LPG storage tank (either owned or rented from a supplier)
  3. A regulator, gas meter/governor, and supply pipe from tank to boiler
  4. Installation by a Gas Safe registered engineer who holds the LPG qualifications
  5. Commissioning and Building Regulations notification (Part J)

Cost Breakdown

Boiler

LPG-compatible condensing boilers are sold by most mainstream manufacturers (Worcester Bosch, Vaillant, Ideal, Baxi). Combi boilers handle heating and hot water in one unit; system boilers work with a separate cylinder. For properties with multiple bathrooms, a system boiler and unvented cylinder is usually recommended.

Boiler TypeSupply CostFitted Cost
LPG combi boiler (24–28 kW)£900–£1,600£1,500–£2,800
LPG system boiler (24–32 kW)£800–£1,500£1,400–£2,600
LPG regular (heat-only) boiler£700–£1,300£1,200–£2,400

Fitted costs include gas engineer labour (1–2 days), flue, controls, and commissioning. Excludes tank and tank installation.

LPG Tank

The tank stores propane at your property. You can buy or rent it:

  • Rented tank (most common): the supplier owns the tank and you pay an annual rental fee of £60–£120/year. You must buy your gas from that supplier. Tank installation is often free or heavily subsidised on a long-term supply contract.
  • Owned tank: you pay £900–£2,500 to buy the tank outright (depending on size) and are then free to get competitive quotes from any LPG supplier.
Tank SizeTypical UseBuy CostRental (per year)
500 litresSmall flat / occasional use£900–£1,400£60–£90
1,000 litres2–3 bed property£1,100–£1,800£80–£100
1,500 litres3–4 bed property£1,500–£2,200£90–£120
2,700 litresLarge property / high use£2,000–£2,800£100–£150

Above-ground tanks must meet the separation distances in Liquid Gas UK (formerly UKLPG) Code of Practice 1. A tank of 500 to 2,500 litres needs 3 m clear of any building, boundary, property line or fixed source of ignition, cut to 1.5 m if a fire wall is built; up to 500 litres it is 2.5 m, and above 2,500 litres it is 7.5 m.1 Underground tanks have different siting rules and cost more to install (£1,500–£3,500 installation) but may be preferred for aesthetic or planning reasons.

Total Conversion Costs

ScenarioEstimated Total Cost
Oil-to-LPG boiler swap only (tank already present)£1,400–£2,800
Oil-to-LPG full conversion (new boiler + tank)£2,500–£5,000
Electric-to-LPG (new CH system + boiler + tank)£6,000–£14,000
LPG boiler replacement (existing LPG system)£1,500–£2,800

Running Costs in 2026

LPG prices fluctuate with oil markets and exchange rates. As of mid-2026, bulk LPG delivery is priced at approximately 55–75p per litre. Propane has a calorific value of around 25.3 MJ/litre, giving an energy cost of roughly 7–10p per kWh (compared with 7.97p/kWh for mains gas under the price cap for 1 October to 31 December 2026, plus a 29.68p daily standing charge).2

For a 3-bedroom home using 16,000 kWh of heat per year through a 90%-efficient condensing boiler:

FuelApprox. Annual Cost (2026)
Mains natural gas£560–£900
LPG (bulk tank)£1,250–£1,800
Heating oil (kerosene)£1,000–£1,600
Air source heat pump (with good CoP)£650–£1,100
Direct electric (storage heaters)£2,400–£3,500

LPG sits between oil and mains gas in running cost. The gap over mains gas is significant; LPG makes most sense where the mains grid is absent, oil infrastructure is already in place (switching tank size or supplier), or where the connection cost to the mains grid (which can be £3,000–£20,000+) makes conversion uneconomical.

Grants and Incentives

As of 2026, there are limited direct grants for LPG specifically:

  • Boiler Upgrade Scheme (BUS): This scheme funds air-to-water heat pumps (£7,500, raised to £9,000 in eligible off-gas-grid properties from 21 July 2026 to 31 March 2027), air-to-air heat pumps (£2,500), ground source heat pumps (£7,500), and biomass boilers (£5,000), LPG boilers do not qualify.3
  • ECO4: Household energy efficiency scheme. LPG boilers may qualify for lower-income households in certain circumstances; check GOV.UK’s Find ways to save energy in your home service.4
  • Home Upgrade Grant (HUG2): ran April 2023 to March 2025. In England the successor is the Warm Homes: Local Grant, run by councils for owner-occupiers on a household income of £36,000 or less in an EPC D to G home.56

If you are off-grid and considering a conversion, an air source heat pump may now be the better long-term investment, lower running costs, BUS grant available, and no fuel delivery dependence. The upfront cost is higher (£8,000–£15,000 installed) but payback improves significantly with the grant and current electricity vs LPG prices.

Regulations

All gas work on LPG appliances must be carried out by a Gas Safe registered engineer, and the engineer must be competent for the specific work.7 You can check registration at gassaferegister.co.uk. LPG counts as a “gas” under the Gas Safety (Installation and Use) Regulations 1998, which cover any gas fitting or gas storage vessel,8 and it requires Building Regulations notification under Part J, combustion appliances and fuel storage systems.9 Your engineer should provide a Building Regulations compliance certificate on completion.

Notify your home insurer before converting, changing fuel type is a material fact under most policies.

References (9)

Figures in this note were checked against the sources below on 10 September 2026. Superscript numbers in the text point to them. Every source the site cites, by topic.

  1. 1technicalvery strongHealth and Safety Executive, guidance.RN-TNB7SUHSE's separation distance table for bulk LPG storage vessels, by capacity, giving one distance that applies equally to buildings, boundary, property line and fixed sources of ignition. Single vessel 0.05-0.25 tonnes (typical water capacity 150-500 litres): 2.5 m without a fire wall, 0.3 m with, 1 m between vessels. Over 0.25 to 1.1 tonnes (over 500 to 2,500 litres): 3 m without, 1.5 m with. Over 1.1 to 4 tonnes (over 2,500 to 9,000 litres): 7.5 m without, 4 m with. Points to LP Gas Association COP 1 part 1 for location and spacing and COP 1 part 4 for buried or mounded vessels. The citable substitute for Liquid Gas UK CoP 1, which is paywalled.
  2. 2technicalvery strongOfgem.RN-YYE8U2The live source for any running-cost sum in a heating note. For 1 October to 31 December 2026 the direct debit cap is 26.32p per kWh for electricity with a 54.83p daily standing charge, and 7.97p per kWh for gas with a 29.68p daily standing charge, giving a typical annual dual fuel bill of £1,723, a 4% rise on the previous period. Ofgem states these are the average unit rate and standing charge for direct debit customers in England, Scotland and Wales; gas prices include 5% VAT while electricity carried no VAT in this period. The cap is reset every three months, so any note quoting a pence-per-kWh figure should be dated against this page.
  3. 3technicalvery strongOfgem.RN-9ZGZJYOfgem administers the Boiler Upgrade Scheme, and this is the page that sets the deadlines a homeowner can miss without realising. The installer must be MCS certified, which Ofgem treats as the evidence of technical competence and of products meeting the correct standards. The installer submits the application on the property owner's behalf, and the owner must confirm consent within 14 calendar days or the application may be rejected; confirming consent approves the application only and does not commit the owner to proceeding with that installer. Once an application is approved the installation must be completed within three months, extended to six months for a ground source heat pump, and missing that window means a fresh application and a fresh consent. Eligibility excludes new builds other than qualifying self-builds, social housing and properties already funded for low carbon heating. Ofgem carries out routine checks and site audits at any stage including after payment. For problems, the owner should approach the installer first and then escalate through MCS or a consumer code such as RECC.
  4. 4technicalvery strongGOV.UK, guidance.RN-5338K3The government's own recommendation tool, and the neutral link a DIY insulation note should offer instead of a comparison site. It gives personalised home improvement recommendations for property owners in England and Wales, and for each suggestion shows an estimated cost of making the improvement and how much could be saved on bills. It cross-refers to the Boiler Upgrade Scheme, the Warm Home Discount Scheme and the Winter Fuel Payment. A telephone helpline is available Monday to Friday 8am to 6pm except bank holidays, and Saturday 9am to 12pm. The page itself carries no eligibility criteria or scheme figures, so a note quoting grant values must cite the individual scheme pages rather than this one.
  5. 5technicalvery strongGOV.UK.RN-U1PW3GThe England-only successor to the Home Upgrade Grant, delivered by local councils. Eligibility: household income of £36,000 a year or less (with postcode and benefit-based exceptions), privately owned home, EPC rating D to G. Funds wall, loft and underfloor insulation, air source heat pumps, smart controls and solar panels, with the council organising and paying for the work. Explicitly 'only available in England'. Use this whenever a note says HUG closed and a successor is awaited: it is live and taking applications.
  6. 6costvery strongDepartment for Energy Security and Net Zero, guidance.RN-BCN48CA price, true at 2026-07. Warm Homes: Local Grant, policy guidance for local authorities (updated July 2026), government guidance cited for the figures and rules it sets out
  7. 7technicalvery strongHealth and Safety Executive, guidance.RN-RJTAHSHSE's gas safety answers for homeowners and occupiers: what to do if an appliance is suspected unsafe, and the advice that all gas appliances, flues and pipework be installed, maintained and serviced annually by a Gas Safe registered installer. HSE is the enforcing authority for gas safety, so this is the regulator's own position.
  8. 8technicalvery strongThe National Archives (legislation.gov.uk), legislation.RN-UFY1XPRegulation 3(1) makes it unlawful for any person to carry out work in relation to a gas fitting or gas storage vessel unless he is competent to do so, and 3(2) places the duty to ensure that on the employer, on every other employer or self-employed person with any control over the work, and on anyone who required the work to be done at a place of work under their control. Regulation 3(3) goes further: no employer may let an employee, and no self-employed person may themselves, carry out work on a gas fitting or service pipework unless that employer or self-employed person is a member of a class of persons approved by the Health and Safety Executive, which in practice is registration with the Gas Safe Register. Regulation 3(4) exempts only replacing a hose or regulator on a portable or mobile space heater and replacing the hose connecting a re-fillable cylinder to installation pipework. Regulation 3(7) makes it an offence to falsely pretend to be a member of an approved class. This is the legal basis for saying a boiler must be fitted by a Gas Safe registered engineer.
  9. 9technicalvery strongMinistry of Housing, Communities and Local Government.RN-I320EKThe landing page for Approved Document J, 2010 edition incorporating 2010, 2013 and 2022 amendments, in force from 1 October 2022. It covers air supply, discharge of combustion products and protection of the building for solid fuel, gas and oil appliances, and the information to be provided for hearths, fireplaces, flues and chimneys. The 2022 amendment extended the provisions and guidance on carbon monoxide alarms. This is the document behind hearth thickness, flue size and clearance-to-combustibles rules for a wood burner or an opened-up fireplace.

  1. Separation distances, Health and Safety Executive, accessed 10 September 2026. hse.gov.uk

  2. Energy price cap unit rates and standing charges, Ofgem, accessed 10 September 2026. ofgem.gov.uk

  3. Boiler Upgrade Scheme: guidance for property owners, Ofgem, accessed 10 September 2026. ofgem.gov.uk

  4. Find ways to save energy in your home, GOV.UK, accessed 7 September 2026. gov.uk

  5. Apply for the Warm Homes: Local Grant to improve a home, GOV.UK, accessed 10 September 2026. gov.uk

  6. Warm Homes: Local Grant, policy guidance for local authorities (updated July 2026), Department for Energy Security and Net Zero, accessed 15 September 2026. Priced at 2026-07, so no calibration is needed. assets.publishing.service.gov.uk

  7. Gas safety - Home owners, Health and Safety Executive, accessed 10 September 2026. hse.gov.uk

  8. The Gas Safety (Installation and Use) Regulations 1998, regulation 3: qualification and supervision, legislation.gov.uk, accessed 10 September 2026. legislation.gov.uk

  9. Combustion appliances and fuel storage systems: Approved Document J, GOV.UK, accessed 10 September 2026. gov.uk