LPG Boilers and LPG Heating

LPG stands for Liquefied Petroleum Gas: a fossil fuel that exists as a gas at normal temperature and pressure but turns to liquid under modest pressure or cooling, which is what allows it to be delivered by road and stored in a tank at your home rather than piped in from a grid¹. It is the fuel of choice for 193,000 UK homes, most of them in rural areas beyond the reach of the mains gas network². Around two million UK properties are off-grid in total and depend on alternative fuels for heating and cooking, and LPG is one of the main options alongside heating oil, solid fuels and electricity³.

For a household thinking about energy independence, LPG sits in an interesting position. It frees a home from the gas grid and from a gas supplier, but it replaces that dependence with dependence on a delivery company, a tank that is usually owned by that company, and a fuel that is a by-product of the oil and gas industries⁴. This page explains what LPG is, how LPG boilers differ from natural gas appliances, what bulk tanks and cylinders involve, and what the fuel costs to run.

Understanding LPG and its origins

LPG is a by-product of two large energy industries: the processing of natural gas liquids and the refining of crude oil¹. It is not a fuel that is drilled or mined for its own sake; it emerges from the supply chains that produce mains gas and petrol, and its availability and price follow those markets. The term covers both propane and butane, two closely related gases, and in the UK the propane form is what heats most homes⁸.

At normal temperature and pressure LPG is gaseous. It changes to a liquid when subjected to modest pressure or cooling, and in liquid form the tank pressure is about twice the pressure in a normal truck tyre, which means it is very safe when properly handled¹. That liquid state is the whole trick of the fuel: a large amount of energy fits into a small tank, and it can be easily stored in bulk tanks or portable cylinders, so providing energy wherever it is needed¹.

LPG is a fossil fuel and produces carbon dioxide when it is burnt, so it is not environmentally friendly in the way a heat pump or solar thermal is⁴. The trade body describes it as the lowest carbon conventional fuel available to off-grid homes, emitting 33% less CO2 than coal, and notes that because it readily evaporates, LPG poses no environmental risks in the event of spillages⁸. Those claims are the industry's own, and they should be read as such: LPG is cleaner than the fuels it usually replaces, but it is still a fossil fuel.

Is LPG heating right for you?

In the UK, 84% of domestic properties are connected to the gas grid, but some two million properties are off-grid and therefore depend on alternative fuel sources for heating and cooking³. Off-gas-grid households use a range of other fuels, including heating oil, LPG, solid fuels, mains electricity and microgeneration⁹. LPG's 193,000 homes are a minority within that off-grid total, and they are typically rural properties where oil has been the traditional alternative².

LPG suits homes that want a wet central heating system, with a boiler and radiators, but have no mains gas pipe. It can be used across multiple applications such as cooking, hot water and heating a property⁸. Compared with the other off-grid options, the cost of LPG installation is significantly cheaper than electric, oil and air source heat pumps, according to the trade body³.

For households on LPG looking to move off fossil fuels, the Boiler Upgrade Scheme in England and Wales offers £9,000 towards an air-to-water or ground source heat pump for eligible off-grid properties heated by LPG or oil, a higher grant than the £7,500 available to on-gas homes¹⁰. In Wales, low income households in some council areas have been able to claim a one-off £200 Heating Oil and LPG Payment towards fuel costs¹². A parliament research briefing describes the scheme as providing upfront grants of up to £7,500, or £9,000 for heating oil and LPG users, to help with the cost of low carbon heating⁷.

Types of LPG boiler explained

An LPG boiler is, mechanically, much the same animal as a mains gas boiler. The same three configurations exist: combi boilers that heat water on demand with no cylinder, system boilers that work with a sealed cylinder, and regular, heat-only boilers fed by a loft tank, often in an open-vent setup. The differences from mains gas are in the fuel side, not the water side: the gas comes from a tank in the garden rather than a pipe in the street, and the burner is set up for propane or butane rather than natural gas.

Some boilers designed for mains gas can be converted to use LPG, which matters to households that already own a serviceable appliance⁴. Conversion is a job for a registered engineer, not a DIY task, and not every model is convertible. If you are weighing the three configurations, the same logic applies as on the gas grid: a combi suits smaller homes with one bathroom, a system boiler suits homes with higher hot water demand, and a heat-only boiler suits homes with an existing cylinder and loft tanks.

LPG boilers also have a future role in hybrid systems. Industry guidance notes that oil and LPG boilers can also be used alongside a heat pump in a hybrid setup¹³, and the same guidance states that the combination of a heat pump with an LPG or oil condensing boiler along with biofuel can significantly reduce carbon emissions. The Boiler Upgrade Scheme treats LPG heating as a fossil fuel system, so an LPG boiler is an eligible system to be replaced under the scheme¹⁴.

Efficiency and emissions: 0.241 kgCO2/kWh at 93 per cent

The official worked example used in the building regulations for England, Approved Document L Volume 1, is an LPG boiler with emissions of 0.241 kgCO2/kWh and primary energy of 1.141 kWhPE/kWh at 93% efficiency⁶. The same document's comparison case is an old oil-fired boiler with emissions of 0.298 kgCO2/kWh at 85% efficiency⁶. Northern Ireland's building regulations discussion document uses the same figures for its worked example of a fuel change: an LPG boiler with emissions of 0.241 kgCO2/kWh at 93% efficiency, giving a primary energy result of 1.23 kWhPE/kWh, which is acceptable¹⁵.

Since February 2023, the minimum efficiency standard for new and replacement condensing standard or combination gas boilers, including LPG, has been 92%¹⁶. The comparable standards for oil are 91% for condensing standard boilers and 86% for condensing combination boilers¹⁶. In practice, a modern LPG condensing boiler will run at or above these figures, and the 93% used in the official example is a realistic expectation for a well-specified appliance.

LPG is an efficient fuel, so you get a good return on every unit of energy⁴. The industry also claims that LPG produces 90% less carbon monoxide and 50% less smog than mains natural gas⁸. Those local air quality figures are the trade body's own, but the CO2 position is well established: at 0.241 kgCO2/kWh, an LPG boiler emits less per unit of heat than an oil boiler at 0.298 kgCO2/kWh, though more than a heat pump drawing low carbon electricity.

Installation costs less than most off-grid rivals, running costs high

The installed cost of an LPG boiler is reported at £1,900 to £3,000, while one distributor figure puts a basic LPG boiler unit at about £350 before installation; the two figures differ because one covers the appliance alone and the other the fitted job³. As with all boiler work, prices are installer-quoted and vary with the model and the amount of pipework and tank work needed. For context, a heat-only oil boiler costs £1,200 to £2,450 with installation adding £500 to £2,000, and biomass boilers cost £5,000 to £10,000 for the appliance with installation between £8,000 and £15,000¹⁷.

Running costs are where LPG hurts. The government estimates that a litre of LPG converts to 7.1 kWh, and in July 2025 a litre cost an average of 57 pence, according to Sutherland Tables, which collects domestic fuel pricing data⁴. From 1 January 2026 the standard assessment fuel prices put bulk LPG at 9.60 p/kWh and bottled LPG at 12.01 p/kWh⁵. A parliament briefing puts the annual cost of bulk propane heating for a typical three-bed semi-detached house at £1,800 to £2,200 as of March 2026⁷.

The biggest disadvantage of LPG is that it is one of the most expensive heating fuels¹⁹, and Energy Saving Trust states the position plainly: "LPG is the most expensive of the three fuel types, but it has less CO2 emissions compared to oil."²⁰ Official guidance notes that the cost of heating a typical three bedroom house is 100% higher with LPG than with mains gas⁹. On top of the fuel itself, the tank usually brings an ongoing annual rental charge, and homeowners are usually tied into long contracts, which limits your options when it comes to finding a better deal¹⁹.

Storing LPG at home

LPG reaches a home in one of two forms: a bulk tank, which is refilled by road tanker, or portable cylinders, which are swapped or refilled individually¹. Bulk tanks suit homes with steady heating demand and somewhere to put the tank; cylinders suit lower demand, such as a cooker or a small heater, and carry the higher unit rate of the two⁵.

Ownership is the point that surprises most households. Unlike liquid fuel tanks, the tank is usually owned by the company that supplies the gas, which means an ongoing annual rental charge will apply, and homeowners are usually tied into long contracts¹⁹. You might alternatively need to buy your tank from your supplier, which adds to the cost in a different way⁴. Either way, the tank is a lock-in: switching supplier means transferring the tank or having a new one installed⁴.

On siting, tanks can be buried below ground to improve the aesthetics of a building, an option worth knowing about where an above-ground tank would spoil a garden or a view³. The building regulations guidance on combustion appliances and fuel storage systems, Approved Document J, covers LPG storage installations with capacities up to 1.1 tonne²¹. In England, installing a fuel tank is considered to be permitted development, not needing planning permission, subject to limits and conditions on the installation²². Planning permission is not normally required for the installation or replacement of a boiler or heating system if all the work is internal²³.

Two practical points count in LPG's favour against oil. LPG tanks can be left on site for up to 30 years, whereas oil tanks need replacing every 15 to 20 years⁸. And because LPG readily evaporates, it poses no environmental risks in the event of spillages⁸, a real consideration for homes near watercourses. Telemetry systems can alert the supplier when fuel is low, making deliveries manageable and efficient³.

Keeping your LPG system safe

The rules for LPG appliances are the rules for gas appliances. The Health and Safety Executive strongly advises that all gas appliances, flues and pipework should be installed, regularly maintained and serviced at least annually by a Gas Safe registered engineer²⁵. Always use a Gas Safe registered engineer to fit, fix and check your appliances, and have all your gas appliances checked every year²⁶. Only Gas Safe registered engineers are legally allowed to install boilers²⁷. When booking, check the engineer's registration covers LPG work, not just mains gas.

Warning signs are the same as for any gas boiler. A gas flame should be crisp and blue; if it is burning lazy and orange, have the appliance looked at²⁶. Carbon monoxide is the silent risk with any fuel-burning appliance, and an audible CO alarm is the standard precaution; our page on carbon monoxide safety covers placement and standards.

If you smell gas or suspect a leak, the steps are fixed and worth memorising²⁸:

1. Open windows and doors to help ventilate the gas²⁸.
2. Turn off the gas supply at the meter as well as any gas appliances²⁸.
3. Call the National Gas Emergency number on 0800 111 999²⁸.

Do not smoke or use any naked flames, do not touch any electrical switches, because turning a switch on or off could ignite a gas leak, and do not enter a cellar, even if your gas meter is located in the cellar²⁸. LPG is not odourless, making it easier to detect leaks⁸, but an odour is a late warning, not an early one: annual servicing is what catches problems before they become leaks.

LPG versus oil and mains gas

Against mains gas, LPG loses on cost and wins on availability. The main difference between the two is that LPG is delivered by road and stored in a tank rather than being piped directly into your home⁴, and heating a typical three bedroom house costs 100% more with LPG than with mains gas⁹. Against oil, the comparison is closer and less settled.

On carbon, LPG emits 12% less CO2 than oil according to the trade body², while the bioLPG page from the same organisation gives a figure of up to 20% less than oil²⁹; the two figures differ, and both are industry claims. Independent advice is more cautious, saying only that the carbon emissions from LPG are slightly lower than oil¹⁹. On cost, LPG is the most expensive of the three fuel types²⁰. On the appliance side, oil boilers have a wider established market: installation costs for all three types of oil boiler can vary from £500 up to £2,000, with heat-only oil boilers at £1,200 to £2,450¹⁷.

For a household weighing LPG against oil boilers, the honest summary is that LPG burns a little cleaner, costs a little more to run, and comes with a tank you do not own. Oil gives you a tank you do own, but one that needs replacing within 15 to 20 years and that carries spillage risk⁸. Neither fuel offers the independence that a heat pump plus solar does, because both leave the household buying a fossil fuel by the tanker-load.

The future of LPG: switch-over timelines, bioLPG and hybrids

LPG's long-term position is fixed by policy. The UK government's stated ambition is to end the installation of gas boilers by 2035 at the latest³⁰, and its heat pump investment roadmap aims to phase out the installation of new and replacement natural gas boilers by 2035 at the latest³¹. For oil and LPG boilers specifically, the Climate Change Committee noted in October 2023 the delayed phase-out date for oil and LPG boilers, moved from 2026 to 2035, and assessed that a 2035 phase-out date for fossil boilers is potentially compatible with Net Zero³². No legally binding ban exists today, and existing LPG boilers are not being removed; the dates concern new installations. Our page on the gas boiler ban covers what is actually law and what is ambition.

BioLPG is the industry's answer to that trajectory. BioLPG is chemically identical to LPG and compatible with all LPG products, with no changes to infrastructure or appliances required²⁹. It emits 33% less CO2 than coal and up to 20% less than oil, on the trade body's figures²⁹. Supply today is limited, so a household buying an LPG boiler should treat bioLPG as a possible future fuel rather than a present one.

The hybrid route is the most practical bridge. Industry guidance states that the combination of a heat pump with an LPG or oil condensing boiler along with biofuel can significantly reduce carbon emissions¹³. In a hybrid, the heat pump covers most of the year's heating and the LPG boiler tops up in the coldest weather, cutting fuel use without requiring the whole system to be replaced at once. The £9,000 Boiler Upgrade Scheme grant for off-grid LPG and oil homes¹⁰ makes the full heat pump route cheaper than it has ever been for those households, though the scheme's rules treat biomass as an option that may replace fossil fuel heating systems fuelled by oil, LPG and coal³³.

For energy independence, the direction of travel is clear: LPG is a comfortable, familiar technology that keeps a wet heating system running off the gas grid, but it does not remove a household's dependence on fossil fuel deliveries, supplier contracts and a tank owned by someone else. A household that installs LPG today should do so knowing it is a way station, not a destination.