Heat Pumps vs Gas Boilers – Which Is Best & Running Costs

Heat pumps and gas boilers both keep UK homes warm and deliver hot water, but they operate on very different principles. That difference affects efficiency, running costs, carbon emissions, and how your heating feels day to day.

Where a gas boiler burns fuel to make heat, a heat pump moves heat from outside air into your home. In 2026, with Ofgem energy prices shifting and the Boiler Upgrade Scheme still open, understanding how these two technologies compare has never mattered more for homeowners making long-term decisions.

How Each System Works

A gas boiler takes natural gas or LPG and combusts it to heat water that then feeds radiators or underfloor circuits. When selecting the right boiler type, it is worth knowing that modern condensing boilers are typically 90 to 94% efficient, meaning you lose a small amount of energy in the combustion process.

An air-source heat pump (ASHP) uses electricity not to generate heat directly, but to transfer it from outside air into your home. Even on cold days it can deliver more heat than the electricity it uses. The efficiency is measured as a Seasonal Coefficient of Performance (SCOP) rather than a percentage.

The key distinction in plain terms: gas boilers convert fuel to heat. Heat pumps move heat from the air. That is why heat pumps can appear far more efficient in theory, though the real-world economics depend heavily on energy prices and installation quality.

For properties with more specialist heating needs such as boiler types for swimming pools, the considerations differ again from standard home heating systems.

Watch Our Video Comparison on Boilers vs Heat Pumps

What the Numbers Actually Look Like in 2026

This is where the original heat pump marketing often oversimplifies things. A heat pump’s running cost advantage depends on two factors working together: how efficiently the specific installation performs (SCOP), and how much your electricity tariff costs versus gas.

Based on the Ofgem Q2 2026 price cap, gas costs 5.7p/kWh and electricity costs 24.7p/kWh. That means electricity is currently approximately 4.3 times more expensive per unit than gas. For a heat pump to match a gas boiler’s running cost, it needs to deliver roughly 4.3 units of heat per unit of electricity, which requires a SCOP of around 4.0 to 4.3.

The honest reality: well-installed UK heat pumps typically achieve SCOPs of 2.8 to 3.5 in real-world conditions, based on monitored data from the Energy Saving Trust and the Heat Pump Monitor programme. At those SCOP levels, a heat pump on the standard Ofgem tariff runs at broadly similar cost to gas, with a gap of roughly £30 to £80 per year in favour of gas on most standard homes. The gap can swing significantly with the right electricity tariff, as described below.

For those managing thermostat controls, the nest thermostat features and benefits guide covers how smart scheduling interacts with both heat pump and gas boiler systems to reduce running costs further.

Real Hourly Running Costs: Heat Pumps vs Gas Boilers

The figures below are based on the Ofgem Q2 2026 cap rates (gas 5.7p/kWh; electricity 24.7p/kWh on standard tariff, or approximately 15p/kWh on a specialist heat-pump off-peak tariff). Real-world costs vary with insulation, outdoor temperature, and thermostat settings.

Small Home (70 to 90 m²)

A smaller property typically needs around 8 to 12 kW of heat on a cold day.

• Gas boiler: approximately £0.90 to £1.30 per hour
• Air-source heat pump (standard tariff): approximately £1.00 to £1.50 per hour
• Air-source heat pump (off-peak tariff): approximately £0.60 to £0.90 per hour

Medium Home (90 to 120 m²)

A 3-bedroom semi-detached typically needs 12 to 18 kW of heat at peak. For central heating pump replacement costs on this type of system, the central heating pump pricing information guide covers what to expect.

• Gas boiler: approximately £1.30 to £2.00 per hour
• Air-source heat pump (standard tariff): approximately £1.50 to £2.30 per hour
• Air-source heat pump (off-peak tariff): approximately £0.90 to £1.40 per hour

Large Home (120 to 160 m²)

A bigger property at peak demand might need 20 to 30 kW. The heat pump’s efficiency advantage plays a bigger role here, but the electricity price ratio still determines whether standard tariff running costs are competitive.

• Gas boiler: approximately £2.00 to £3.00 per hour
• Air-source heat pump (standard tariff): approximately £2.30 to £3.50 per hour
• Air-source heat pump (off-peak tariff): approximately £1.40 to £2.10 per hour

Ultra-Efficient Scenario: High Insulation and Off-Peak Tariff

For a well-insulated home on a specialist heat pump electricity tariff (such as Octopus Cosy or Economy 7, with off-peak rates of 7 to 15p/kWh), the economics shift clearly in the heat pump’s favour:

• Heat pump: approximately £0.60 to £1.20 per hour
• Gas boiler: approximately £1.30 to £2.00 per hour

In this scenario, the heat pump beats gas on running cost and on carbon. This is where the technology is genuinely at its best.

Annual Bills: A Realistic 2026 Picture

For a typical 3-bedroom home requiring approximately 12,000 kWh of heat per year, based on Ofgem Q2 2026 cap rates:

• Gas boiler (90% efficient): approximately £760 to £900 per year
• Air-source heat pump (standard tariff, SCOP 3.0): approximately £800 to £960 per year
• Air-source heat pump (off-peak tariff, SCOP 3.0): approximately £400 to £600 per year
• LPG boiler: approximately £1,800 to £2,200 per year
• Oil boiler: approximately £1,400 to £1,800 per year

The key takeaway: on a standard electricity tariff, gas and a well-installed heat pump run at broadly comparable annual cost. On a specialist off-peak tariff, the heat pump wins clearly. For off-grid homes currently on LPG or oil, a heat pump already makes strong financial sense even at standard electricity rates.

Upfront Costs: What You Pay Today

Running costs only tell half the story. The upfront difference between the two technologies remains significant.

A typical gas combi boiler installation in a UK home costs between £2,500 and £4,500 fully installed. When comparing best combi boilers for small spaces, factors such as output rating, warranty length, and brand support matter significantly alongside price.

An air-source heat pump installation typically costs £8,000 to £14,000 before any grants. The Boiler Upgrade Scheme (BUS) provides £7,500 directly off the installed cost when using an MCS-certified installer, bringing the effective net cost to £500 to £6,500. The BUS is confirmed open until at least March 2028 and is available for properties in England and Wales.

The electric boiler benefits in the UK guide provides a useful third comparison point for households considering all-electric heating options alongside heat pumps.

Comfort and Home Suitability

A heat pump delivers steady, lower-temperature heat that works best matched with low-temperature emitters: underfloor heating circuits or oversized radiators designed for flow temperatures of 35 to 45 degrees rather than the 60 to 70 degrees a gas boiler typically produces. Well-insulated homes with good airtightness get the most from heat pump technology.

Gas boilers deliver hotter flow temperatures and warm rooms quickly, which tends to feel more intuitive in older, draughtier homes or where insulation is difficult to upgrade. The Worcester Bosch boiler advantages and disadvantages guide covers how specific high-efficiency gas models perform in these situations.

A heat pump also requires a suitable outdoor location for the external unit. This is straightforward for a detached home with a garden; more challenging in terraced houses with shared walls or flats where space is tightly constrained.

Who Should Choose What?

Most UK households fall into one of three situations.

Still on Mains Gas with Budget or Insulation Constraints

A modern high-efficiency gas boiler still makes excellent sense. When considering the types of green boilers available alongside standard condensing options, there are eco-minded gas alternatives that reduce emissions without the full heat pump installation cost.

For those looking at specific high-efficiency models, the main eco compact 30kw boiler features review covers a well-regarded compact option suited to medium-sized properties.

Well Insulated with Outdoor Space and Tariff Flexibility

An air-source heat pump can compete on running cost and clearly outperform on carbon emissions. Getting your electricity tariff right is not optional here; it is the single biggest variable in whether the heat pump saves money or costs more than gas. Specialist tariffs from Octopus, OVO, and EDF are designed specifically for heat pump households.

Rural or Off-Grid Properties

LPG and oil boilers have filled important roles in rural UK, but heat pumps are increasingly compelling for these properties because the comparison is against expensive off-grid fuels rather than mains gas. The natural gas boiler advantages in the UK guide covers the LPG vs mains gas comparison in detail.

A Pragmatic Path for Most UK Households

For many homeowners the answer in 2026 is not “either gas or heat pump today.” A staged approach often makes more financial sense:

• Improve insulation and controls now. This reduces bills regardless of which heating system you have, and is often required before a heat pump installation qualifies for the BUS grant anyway. The Viessman 20kw boiler specifications review covers one high-efficiency gas option suited to better-insulated properties.
• Upgrade controls. Smart thermostats for efficient heating with scheduling and modulation can cut gas usage by 10 to 20% on its own, regardless of whether you switch to a heat pump later.
• Replace an ageing boiler if needed. A new A-rated gas boiler is the right call for immediate reliability and comfort, particularly if the heat pump transition is 3 to 5 years away.
• Plan the heat pump transition. When the home is ready, financially and physically, the combination of a well-insulated building, an off-peak electricity tariff, and the BUS grant makes the economics considerably more attractive than in 2023 or 2024.

This staged approach avoids rushed decisions and spreads investment while still cutting costs and emissions over time.

Final Thought

Heating choice in the UK is not just about technology. It is about the home you live in, the fuel available, the insulation you can realistically achieve, and how you use heat every day. As you consider these factors, understanding central heating costs in the UK across different system types is an important part of setting realistic long-term budgets.

Whether you stay with gas and plan for a heat pump transition later, or move to electric heat now, the decisions that tend to pay off best are those that match your house’s actual condition and your household’s real lifestyle, not the most optimistic scenario from a marketing brochure.

Frequently Asked Questions

Is a heat pump cheaper to run than a gas boiler in 2026?

On a standard Ofgem tariff at Q2 2026 prices (gas 5.7p/kWh, electricity 24.7p/kWh), running costs are broadly comparable for a well-installed heat pump achieving SCOP 3.0 to 3.5. The difference is typically £30 to £80 per year in favour of gas at standard rates. On a specialist off-peak heat pump tariff (7 to 15p/kWh), a heat pump can be £300 to £600 cheaper per year than gas, depending on insulation level and SCOP.

What is SCOP and why does it matter?

SCOP stands for Seasonal Coefficient of Performance. It measures how many units of heat a heat pump produces for every unit of electricity it consumes, averaged across a full UK heating season. A SCOP of 3.0 means 3 kWh of heat for every 1 kWh of electricity. Real-world UK air source heat pumps typically achieve SCOPs of 2.8 to 3.5. Installation quality, insulation level, flow temperature, and outdoor conditions all affect SCOP significantly.

How much does the Boiler Upgrade Scheme grant cover?

The Boiler Upgrade Scheme (BUS) provides £7,500 directly to your MCS-certified installer, which is deducted from your final invoice. You never handle the grant money yourself. It is available for air source and ground source heat pump installations in England and Wales. The property must have a valid EPC with no outstanding recommendation to insulate loft or cavity walls. The BUS is confirmed open until at least March 2028.

Can a heat pump work in an older or poorly insulated UK home?

Heat pumps can work in older homes, but efficiency drops significantly with poor insulation or inadequate radiators. A heat pump in a draughty property with single glazing and undersized radiators will achieve a lower SCOP, potentially making it more expensive to run than gas on a standard tariff. Addressing insulation and upgrading radiators before installation is strongly recommended, and is in many cases a condition of BUS grant eligibility.

Do I need planning permission for a heat pump?

Most air source heat pump installations in England fall under permitted development rights and do not require planning permission, provided the unit is not installed on a wall or roof facing a highway, is not in a Conservation Area or listed building, and meets certain size and noise limits. Scottish and Welsh rules differ slightly. Always confirm with your MCS-certified installer before proceeding.

What happens to gas boilers after 2035?

The UK Government’s Future Homes Standard targets the phase-out of new gas boiler installations in new-build homes from 2025, and the Heat and Buildings Strategy outlines a longer-term transition away from fossil fuel heating across the existing housing stock. The 2035 date for ending new gas boiler sales in existing homes has faced political uncertainty and should not be treated as confirmed at the time of writing. The BUS grant mechanism suggests the government expects heat pump adoption to grow progressively rather than through an abrupt ban.