Heat pump vs LPG boiler — which is better? (UK guide)

The short answer

For a home heated by LPG (liquefied petroleum gas), an air source heat pump is usually the strongest alternative. An LPG boiler works much like a mains gas boiler — high flow temperatures, existing radiators, low install cost — but the fuel is expensive per unit, prices are volatile, and you typically rent or own a bulk tank with delivery contracts. A heat pump runs on electricity at a SCOP of around 3 to 4, so despite electricity's higher unit price, it is frequently cheaper to run than LPG, which is one of the more expensive heating fuels in the UK. The heat pump costs more to install but qualifies for the £7,500 Boiler Upgrade Scheme grant in England and Wales. The trade-off is the heat pump's lower flow temperature, which may require radiator or insulation improvements in older homes.

LPG is one of the costliest ways to heat a UK home, so many off-grid households compare it directly with a heat pump. Here is how the two stack up.

Heat pump vs LPG — at a glance

Heat pump fuelElectricity
LPG boiler fuelLiquefied petroleum gas (propane)
Typical heat pump SCOPAround 3.0 to 4.0
LPG boiler efficiencyAround 90%+
BUS grant for heat pump£7,500 (England & Wales)

Running costs: why LPG is expensive

LPG is among the more expensive heating fuels per unit of energy in the UK — typically dearer than mains gas and often than oil. An LPG boiler is efficient (around 90% or better), but high efficiency on an expensive fuel still leaves you with high running costs. Prices are also exposed to global energy markets and your supplier's contract terms.

A heat pump consumes electricity, which costs more per kilowatt-hour than LPG — but the heat pump multiplies that energy. With a SCOP around 3 to 4, it delivers 3 to 4 units of heat per unit of electricity. Because LPG is so costly to start with, a well-designed heat pump frequently undercuts it on running cost, and a time-of-use electricity tariff can improve the comparison further.

Factor	Air source heat pump	LPG boiler
Fuel	Electricity	LPG (propane)
Typical efficiency	SCOP ~3.0–4.0	~90%+
Fuel cost per unit	Higher, but multiplied by SCOP	High — among the dearer UK fuels
Running cost	Often below LPG	High and volatile
Carbon emissions	Low and falling	High (fossil fuel)
Tank / storage	None	Bulk tank, often rented

Indicative comparison for guidance. Sources: Energy Saving Trust; Nesta.

Tanks, contracts and installation

LPG usually involves a bulk storage tank — either bought outright or, more commonly, rented from the supplier under a contract that ties you to buying gas from that supplier. These contracts can include minimum order quantities and exit terms, and tank siting has safety distance rules. Switching to a heat pump removes the tank, the deliveries and the contract entirely.

On installation, an LPG boiler replacement is cheap and quick because it reuses existing radiators and pipework. A heat pump costs more up front: it needs an outdoor unit, a hot water cylinder, and often radiator upgrades to suit the lower flow temperature. The £7,500 Boiler Upgrade Scheme grant offsets a large share of that for eligible homes.

Check your contract: if you rent an LPG tank, review the supplier agreement before switching — there may be notice periods or charges for tank removal. Factor this into the comparison, but it is usually outweighed by removing an expensive recurring fuel bill.

Hot water, controls and day-to-day living

An LPG boiler — often a combi or system boiler — heats on demand at high temperatures, so hot water and heating feel much like mains gas. The downside is the ongoing logistics: monitoring the tank level, arranging refills before you run low, and the risk of a cold home if a delivery is delayed in winter. Bulk LPG also ties you to a supplier and their pricing.

A heat pump removes that logistics burden entirely. It heats a hot water cylinder rather than producing instant hot water like a combi, so sizing the cylinder correctly to the household's demand matters — a well-sized cylinder gives plenty of hot water, while an undersized one can run short. Once set up with weather compensation and good controls, the heat pump runs steadily in the background with no fuel to manage.

For households frustrated by LPG deliveries, price volatility and supplier contracts, the shift to a self-contained electric system is often as much about convenience and predictability as it is about cost.

Carbon and suitability for older homes

LPG is a fossil fuel, so its carbon footprint is fixed and high. A heat pump's emissions track the electricity grid, which keeps getting cleaner — so the system decarbonises over time without any equipment change.

The deciding practical question is whether your home suits a heat pump. Heat pumps run at lower flow temperatures than LPG boilers, so they depend on good insulation and adequately sized emitters. A well-insulated home with reasonable radiators is straightforward; a draughty solid-wall property may need fabric and radiator improvements first. An MCS-certified installer carries out a heat loss survey to design the system and confirm what upgrades, if any, are needed. For some hard-to-treat homes a hybrid system — heat pump plus a small back-up boiler — can be a stepping stone.

Frequently asked questions

Is a heat pump cheaper than LPG?

Usually, yes. LPG is one of the more expensive heating fuels per unit in the UK, and a heat pump's efficiency (SCOP around 3 to 4) means it delivers several units of heat per unit of electricity. Even though electricity costs more per unit than LPG, the multiplier effect typically makes a well-designed heat pump cheaper to run than an LPG boiler.

Do I have to keep buying LPG from my tank supplier?

If you rent your bulk LPG tank, your contract usually requires you to buy gas from that supplier, sometimes with minimum quantities. Switching to a heat pump lets you end the fuel deliveries, but check the tank rental agreement first for notice periods or tank-removal charges before you cancel.

Can I get the Boiler Upgrade Scheme grant if I have LPG?

Yes. Off-gas-grid homes, including those heated by LPG, are eligible for the £7,500 air source heat pump grant under the Boiler Upgrade Scheme in England and Wales, provided the property has a valid EPC with no outstanding insulation recommendations and the work is done by an MCS-certified installer. Scotland has separate funding via Home Energy Scotland.

Sources & further reading

Figures on this page are typical UK ranges drawn from published sources and depend on your specific home. They are guidance, not a quotation or guaranteed saving.