November 25, 2021

Heat Pump vs Gas Boiler

Home heating now accounts for roughly 15% of UK carbon emissions, which is in direct opposition to the government’s 2050 carbon neutral ambitions. Because gas boilers are a major source of these emissions, low-carbon options such as a heat pump or hydrogen boilers are anticipated to replace them in the coming years.

However, there are some significant distinctions between gas boilers and heat pumps, and since neither choice is ideal, it’s important to be informed of the disadvantages of each. Alternatively, you can read about the different types of boilers available if a heat pump does not suit your needs.

So, let’s examine how they stack up against one other so you can make a better educated choice about which is best for you and your home.


To begin, what exactly is a heat pump?

Heat pumps, as its name implies, transfer heat from one point to another. They do it by taking heat from the air outside your house or from the ground and using it to heat it.

Heat pumps are divided into three categories:

  • Heat pumps using an air source
  • Pumps that extract heat from the ground
  • Heat pumps with a hybrid design

They collect heat from the air, the ground, or the water and may offer both central heating and hot water, while hybrid heat pumps can supplement heat with a boiler when the weather is really cold.

Heat pumps need very little power to run, and when paired with the fact that they absorb a lot of heat from the environment, they may be quite efficient.

Check out our heat pump guide for more information.


Heat Pumps vs. Gas Boilers

Around 17 million houses in the United Kingdom use gas boilers for home heating, with the majority of the remaining properties relying on oil boilers since they are not linked to the gas network.

Low-carbon heat pumps, on the other hand, are a critical component of the government’s carbon-neutral aspirations.

As a consequence, gas boilers have already been the subject of significant regulation, such as a ban on non-condensing boilers, requiring all new boilers to be at least 90% efficient, and a full ban on gas boilers in all new construction houses beginning in 2025.

However, other experts argue that the drive for a heat pump revolution is fundamentally misguided, citing key problems such as cost and practicality.

Instead, many industry observers argue that switching to a green fuel is significantly simpler than switching to a whole new heating system, which is why many people choose hydrogen boilers that may possibly utilise the current gas network.

With that in mind, let’s see how heat pumps and gas boilers stack up….


Installation complexity


Installation of a gas boiler

In most cases, installing a gas boiler is simple, fast, and painless. There are plenty of Gas Safe Engineers available to install gas boilers in as little as 24 hours.


Installation of a heat pump

Because heat pumps are in lower demand, there are fewer trained installers available to install them, so you may have to wait longer. It also means that they are much more costly to buy and install than gas boilers.

Installing air source heat pumps takes a bit longer than installing gas boilers (between 2 and 3 days).

Ground source heat pumps may take anywhere from four to six weeks to install. This is due to the intrinsic nature of their setup, which necessitates the construction of boreholes and trenches inside the property’s boundaries.



Gas boiler installations are significantly more tempting in terms of speed. Gas boilers are a more faster and more effective alternative if you don’t have hot water or heat.


Comparison of Upfront Costs


The cost of a gas boiler

The typical cost of a gas boiler installation is between £1,500 and £3,000, making it a reasonably priced home heating option.

Boilers are also available on finance in most cases. You can also look into the cost of moving the location of your boiler and reasons you may do this.


Prices for heat pumps

Heat pumps are sometimes highly costly, and their installation is specialised and difficult.

The cost of air source heat pumps ranges from £8,000 to £15,000, whereas the cost of ground source heat pumps including installation is between £18,000 and £25,000.



Again, if you’re on a budget, gas boilers are the way to go. Heat pump prices are expected to drop as demand rises, although they are now much higher.


Comparing Operating Costs


Costs of operating a gas boiler

The typical yearly boiler consumes 13,600 kWh of power, according to official government figures, and the average gas bill in 2020 was £557 (and £706 for electricity).

Electricity is now significantly more expensive than gas, resulting in a very high running economy. For example, electricity costs 3-16p per kWh compared to 3-4p per kWh for gas.

As a result, an air source heat pump may not be less expensive to operate than a gas boiler, particularly in a home with low thermal efficiency. Environmentalists are requesting that the government lower the environmental fee on power as a result of this.


The cost of operating a heat pump

Heat pumps work on electricity, with an estimated 25% of the heat they supply coming from energy and the remaining 75% coming from the air or ground, making them incredibly efficient.

The operating expenses might be exceedingly expensive if they’re placed in a residence with low thermal efficiency, particularly when compared to gas.
This is why an energy audit is necessary prior to installation, which adds even another degree of complexity to heat pumps. This would include evaluating the insulation, heat loss, existing tariffs, and the size of your property.

However, you may be able to use the Renewable Heat Incentive (RHI) to help defray some of the expenses.

The Renewable Heat Incentive (RHI) is a government-funded programme that pays homes for the heat generated by qualified renewable heating systems. From April 2022, the Clean Heat Grant will take its place, with families receiving a grant for the upfront installation expenses rather than a monthly payment after the system is installed.



If correctly placed in a thermally efficient home, a heat pump will likely be less expensive to operate than a gas boiler.

However, since the majority of UK home stock is thermally inefficient, extensive investment in insulation, draught proofing, and glazing may be necessary to reduce heat pump operating costs. The operating expenses of a heat pump will surely be more tempting if the cost of energy is cut.

In its most basic form, efficiency refers to the amount of fuel transformed into thermal energy.


Efficiencies Compared


Efficiency of a gas boiler

A contemporary A-rated gas boiler is roughly 90% efficient, which means it can convert 90% of the energy it consumes into heat energy while only wasting 10%. That implies that for every £1 spent on heating, the flue pipe will lose 10p. Read more about boiler efficiency in our in-depth guide.


Efficiency of heat pumps

Heat pumps are substantially more efficient, with air source heat pumps achieving efficiency ratings of approximately 300 percent and ground source heat pumps exceeding 400 percent.

This implies that for every 1 kWh of power consumed, 3 to 4 times as much heat is generated.

The efficiency of heat pumps is expressed as a COP (Coefficient of Performance) or SCOP (Successive Coefficient of Performance) (or Seasonal Coefficient of Performance). For example, a SCOP of 3 indicates that for every 1 kW of power produced, 3 kW of heat is generated.



Heat pumps come out on top, hands down. When installed appropriately, the total efficiency is significantly better than that of a gas boiler. The thermal efficiency of the building in which they’re placed has an important role in their performance.


Performance & Heat Output


Performance of a gas boiler

When compared to heat pumps, gas boilers are able to offer a high and constant heat output in a very short period of time.

A boiler, for example, has a high flow temperature of approximately 70°C, but an air source heat pump has a radiator system temperature of 35°C to 45°C and a hot water temperature of around 55°C.


Performance of a heat pump

Heat pumps can’t generate heat as quickly as traditional boilers since their output temperature is lower, therefore they’re only suitable for house heating over a longer time.

The maximum flow temperature for heat pumps is 45°C. Gas boilers, on the other hand, can easily maintain a constant temperature of 70°C.
As a result, they are only appropriate for houses with proper insulation and draught proofing.

It usually necessitates the installation of new, bigger radiators, since standard radiators are unlikely to offer the needed heat output, as well as heat pump compatible hot water storage.



Gas boilers are still the best performing alternative for day-to-day uses in the average house. They’re able to sustain greater temperatures year after year, with no seasonal performance dips.

Larger radiators and a big investment in insulation may be necessary to provide the comparable warmth into your house with a heat pump.


Comparison of Carbon Footprints


CO2 emissions from gas boilers

A contemporary A-rated gas boiler produces 215 grammes of CO2 per kWh of heat produced.

These contemporary condensing boilers are much more environmentally friendly than previous non-condensing boilers.

You might save up to 1,220 kg of CO2 per year by replacing your old boiler with a new condensing boiler.

You might save even more if you use a smart thermostat and thermostatic radiator valves. Because of its adjustable learning schedule, you might save up to £75 and 330kg of carbon each year by installing a Nest.


CO2 emissions from heat pumps

The heat pump is a zero-carbon heating equipment since it burns no fossil fuels and only utilises electricity.

Heat pumps are carbon-free. They do, however, operate on grid power, of which only 40% is produced green.

However, this does not imply that the power it consumes is 100% pure, but given that renewables account for about 40% of electricity output in the UK, it is unquestionably better for the environment than gas boilers.



A heat pump is the champ when it comes to emissions from the device itself, since it produces none. However, you’ll need to take power from the grid to feed the gadget, which would have been created using fossil fuels (predominantly).