Heat Pump vs Gas Boiler: A Homeowner’s Guide
Are heat pumps better than boilers? This is like asking whether water is better than cola. The two perform the same function, heating your home, but there is a significant difference in cost, convenience, environmental impact and installation requirements. If you’re considering installing a heat pump instead of a boiler, this guide is for you.
Many homeowners today are comparing the costs and benefits of heat pumps against gas boilers. Rising energy prices, colder winters and concerns for the environment are driving a rise in heat pump consideration, especially when people hear they can get a grant from the government to help with the cost.
You should be aware that a middle ground exists: the hybrid heat pump. This system integrates a heat pump into an existing boiler system, so you can cut gas consumption without giving up on-demand hot water.
This guide will help our readers choose the right heating solution for their homes and other properties, whether you’re switching away from gas or a different heat source.
At Intergas Heating, we help homeowners make informed choices for efficient and reliable heating solutions.
How Do Heat Pumps and Gas Boilers Work?
How a Gas Boiler Works
The short answer: the boiler burns natural gas to heat water, which is distributed to radiators around the building.
Gas boilers are connected to the national gas network.
The burner is turned on either by a manual switch or a radio signal from the thermostat. When the burner switches on, a piezo ignition sparks for a moment before a valve opens to start the flow of gas, which then ignites. The delay prevents a build-up of the gas, which could cause an explosion when lit.
The burner’s gas flame is next to a heat exchanger, through which water is flowing. The narrow channels in the heat exchanger create a large surface area to transfer as much heat as possible to the water.
The hot water is either stored in a tank or distributed to radiators and hot water taps on demand.
How a Heat Pump Works
The short answer: the heat pump draws in ambient warmth and compresses it to generate heat. This heats water, which is pumped to radiators.
Heat pumps come in two types, ground source and air source, depending on where they source ambient heat. Both are powered by electricity and use a system of heat exchangers.
Air source heat pumps use fans to draw in air to a heat exchange coil filled with refrigerant. The refrigerant is naturally much cooler than the ambient air, so it absorbs any thermal energy present. This fluid then vaporises as it increases in temperature, and the vapour flows into a compressor. This compresses the vapour, raising its temperature to between 30 and 50 degrees. The compressed vapour passes through a heat exchanger, like in a boiler, where the thermal energy is transferred to water. The hot water is stored in a tank or distributed to radiators, while the condensed refrigerant is depressurised and flows back to the outdoor coil. Just like in a refrigerator, this fluid is in a closed loop and does not need to be refilled.
Ground source heat pumps are connected to underground pipes filled with thermal transfer fluid (a mix of water and antifreeze) to absorb thermal energy. These are either in vertical boreholes approximately 100m deep or horizontal trenches around two metres deep. At these depths, the ground temperature remains approximately 10-12°C throughout the year.
The fluid absorbs heat from the ground and flows back to the pump, where it passes through a heat exchanger to transfer heat to a refrigerant fluid.
The heat pump compresses this fluid, raising its temperature, before passing it through another heat exchanger to transfer the thermal energy to water.
This water is pumped to radiators to release the thermal energy into the building.
As you can see, air source heat pumps are far simpler machines than ground source heat pumps, with a less invasive installation and fewer fluids to manage.
Because all roads lead to hot water flowing through your radiators, choosing whether to install a heat pump or gas boiler is really a question of what is right for your budget, your home or business and your environmental responsibilities.
Installation Comparison: Heat Pump vs Gas Boiler
Heat Pumps: Installation
Heat pump installation is often complex and customised to the precise situation of your building and the type of heat pump you choose.
Ground source heat pumps require extensive groundworks to lay the pipework, so are mostly used for large properties or new buildings.
Air source heat pump installation usually takes fewer than three days, and involves creating a firm, level base, mounting the machine, electrical wiring and plumbing. Air source heat pumps are suitable for installation on most homes and businesses where there is adequate insulation.
Installation and supply costs for heat pumps can range between £10,000 and £25,000. You might need new radiators and insulation to make the heat pump effective. However, grants are available to help with the costs, with the government offering to pay £7,500 towards heat pump installation when transitioning away from fossil fuels.
Gas Boiler Installation
A typical gas boiler installation is quick and easy, especially if you are replacing a similar boiler. It’s not hard to find a certified engineer, and installation usually takes less than a day.
The average cost of a gas boiler installation falls between £2,700 and £3,500, including the price of the boiler itself.
However, if your property is not yet on the mains gas network, the gas boiler installation becomes more complex. Simply getting connected involves groundworks and internal pipework. This can cost between £400 and £4,000. There are no grants available to help with the cost of a new gas connection.
Air Source Heat Pump vs Gas Boiler Running Costs
Typical Running Cost of a Gas Boiler
Running costs are among the main reasons people look to replace their heating systems and form a large part of the argument for sticking to gas boilers.
Per kilowatt-hour (kWh), gas prices are capped at 7p in 2025, while electricity costs 30p per kWh, making the per-unit fuel costs of gas boilers almost a quarter of those of heat pumps.
However, a per unit approach is only meaningful when you consider efficiency as well. For every unit of fuel, even the most up to date, A-rated gas boiler loses approximately 10% of the energy.
1 kWh of gas generates 0.9 kWh of heat.
According to Ofgem, a 2-3 bedroom house will use an average of 11,500 kWh of gas each year. This figure doesn’t differentiate between gas used for heating, hot water and cooking, but as only 3% of total household energy consumption is for cooking, compared to 61% for heating and 17% for hot water, the annual average gas use via the boiler is closer to 11,040 kWh. It will also be much less if you have high-quality insulation.
At the 2025 rate, this adds up to: 11,040 kWh x £0.07 = £772.80/year to run a gas boiler.
Consider that current UK energy prices are rising annually when you make your decision.
Typical Heat Pump Running Costs
As electricity costs are capped at 30p per unit, meeting this 11,040 kWh target looks far more expensive at face value. However, air source heat pumps typically have a coefficient of performance (COP) of 3.0. This means for every 1 unit of electricity the pump uses, it delivers 3 units of heat energy.
To generate 11,040 kWh of heat for your home, a heat pump will use approximately 3,680 kWh of electricity. At current prices, this is: 3,680 kWh x £0.30 = £1,104/year.
Consider also that most households using gas boilers are not necessarily well insulated, while good insulation is a requirement for heat pump installation. Gas boilers generate high heat quickly to compensate for heat loss in older homes, whereas heat pumps offer a more regular supply at around 50°C.
If your home is well-insulated or has an EPC rating in band B (as many new build homes do), your annual heat demand will be closer to 3,780 kWh of heat or 1,260 kWh of electricity when using a heat pump. That’s just £378 for your annual heating bill, compared to £264.60 if you use gas. The better your insulation, the closer the gap between air source heat pump and gas boiler running costs.
Comparing Heat Pumps vs Gas Boilers: Cost, Efficiency and Emissions
| Heating System | Gas Boiler | Heat Pump |
| Fuel | Natural Gas | Electricity |
| Price per kWh (2025) | 7p | 30p |
| Coefficient of Performance (COP) / Efficiency (%) | 0.9 / 90% | 3.0 / 300% |
| Effective Cost per Heat Unit Generated | 7.8p | 10p |
| Installation Cost range | £2,700 – £7,300 | £10,000 – £25,000 (grants available) |
| CO2 Emissions (tonnes/year) | ~2.0 | 0 – 0.6 (depending on electricity source) |
While electricity is more than quadruple the price of gas, a heat pump uses far fewer units to generate the same amount of heat, with far fewer emissions. However, in the battle of air source heat pump vs gas boiler, convenience and cost often win out.
Is a Heat Pump Better for the Environment Than a Gas Boiler?
Gas boilers burn natural gas, which is a fossil fuel. The energy contained within this gas was generated through photosynthesis in plants that lived millions of years ago. These died, decomposed and released the gas in underground chambers, which are now tapped and piped to homes to burn for heating, hot water and cooking. Each year, the average UK home with a gas boiler emits two tonnes of CO2 into the atmosphere, contributing to the ‘greenhouse effect’ which warms the planet, leading to more extreme weather, less predictable seasons and changes to sea levels and ocean currents.
Gas boilers also carry a risk of leaking harmful gases such as carbon monoxide into your home and your local atmosphere, causing air pollution and long-term health problems.
Heat pumps run on electricity, either from the UK national grid or from solar panels installed on your property. As the UK continues to increase energy production from renewable resources, electricity becomes less reliant on fossil fuel production. Electrifying your home heating can reduce your household CO2 emissions by up to two tonnes every year, especially if you generate power on site.
Intergas takes a sustainability approach to heating solutions, sourcing our materials responsibly and innovating to create ever more efficient systems.
Comparing Heat Pump or Gas Boiler: Which is More Suitable for Your Home?
Choosing your heating solution depends on the condition of your home, such as insulation, proximity to the gas network and budget. For older properties with poor insulation, a boiler will provide quick heat whenever you need it. Heat pumps are best for well-insulated buildings as they rely on high heat retention. As well as a grant to help with heat pump installation, you may be able to get financial help with insulation costs, making this transition much more affordable.
However, the environmental benefits make heat pumps a key part of the UK’s journey to Net Zero carbon emissions. While they are slightly more expensive to run, they do not emit any carbon dioxide or other potentially harmful gases. Heat pumps are completely safe, with no risk of gas leaks or explosions as associated with gas boilers.
If you can cover the initial investment, replacing your current heating system with an air source heat pump is an excellent way to reduce your emissions.
If you’re not ready to give up the comfort of instant heat and hot water, a hybrid heating system combines all the benefits of heat pumps and gas boilers, reducing gas consumption by up to 82.5%. Heat your home with the best of both options by choosing a hybrid heat pump system. Find out more about what hybrid heat pumps are.
FAQs: Heat Pumps or Gas Boilers
Can I get a government grant for a heat pump?
If you are replacing a fossil-fuel based heating system with a heat pump and you own the property, you may be eligible for a £7,500 government grant for heat pump installation in England and Wales.
The property must also have a valid Energy Performance Certificate for the property and be suitable for a low-carbon heating system. You can find out by speaking to an MCS certified heat pump installer.
In Scotland, you may be eligible for a similar £7,500 grant and an additional £7,500 as an interest-free loan.
Find out if you’re eligible for the Boiler Upgrade Scheme.
Are heat pumps better than boilers?
It depends on what defines ‘better’. They are far more energy efficient, generating 3 heat units per unit of fuel compared to 0.9 for most gas boilers. They are better for the environment, running on electricity rather than natural gas, and they are safer to have installed at home.
On the other hand, gas boilers generate more heat, more quickly, so you can guarantee hot water on demand and feel comfortable in a poorly insulated home.
Is a combi boiler gas or electric?
A combi boiler is named for its combined functions of central heating and hot water supply. Combi boilers can be either gas or electrically powered, though gas is the cheaper option.
Does a heat pump replace a boiler?
Heat pumps are designed to replace boilers in home heating systems. They provide central heating and hot water. However, heat pumps store hot water in a tank rather than heating it on demand like a combi boiler does.
Is a heat pump cheaper than gas?
In 2025, there is no measure by which a heat pump is cheaper than a gas boiler. As demand increases, advocates hope that the initial cost of heat pumps will fall. Because heat pumps are electrically powered, they are slightly more expensive to run, despite using a lot less energy. However, if gas prices rise as reserves run out, this may change.
How do I replace my gas boiler with a heat pump?
The first step is to arrange an inspection to check whether or not your home is suitable for a heat pump installation. You should have good insulation and up-to-date radiator systems in place to make a heat pump an effective method of heating.
