Choosing between a heat pump or a gas boiler is a big decision that will likely affect your day-to-day comfort for some time. Before you make a decision, it pays to do your research. If you’ve got this far, you’re likely a carbon-conscious homeowner interested in gas boiler alternatives.
In this post, we compare the environmental impact of air-source heat pumps vs gas boilers. We also examine the difference in running costs, upfront investment, and overall efficiency.
What is a heat pump?
A heat pump extracts thermal energy from the air (or ground) outside, which it uses to heat the water that feeds directly into your radiators and taps.
Though it doesn’t burn fossil fuels, it does require some electricity (we’ll come back to this in the next section).
This sort of heating system is widely used in Europe, where take-up is much higher than in the UK. According to Which? magazine, heat pumps are used in 16% of Europe’s residential and commercial buildings.
In the UK, the majority of homes still use gas central heating (as many as 86%, according to some estimates). So, why are we so reluctant to give up our boilers in this country? What are we clinging on to?
Let’s compare heat pumps vs gas boilers.
Air source heat pump vs gas boiler running costs
On the face of it, running a heat pump is more expensive than a gas boiler because it uses electricity. Anyone who scrutinises their energy bills will know that it’s more expensive to buy electricity than gas.
| Gas | Electricity | |
| Unit rates | 6.04p per kWh | 24.50 per kWh |
| Standing charge | 31.43 per day | 60.10 per day |
Average energy rates in the UK from 1 April to 30 June 2024 (full details at USwitch).
However, this isn’t the whole story because heat pumps are much more efficient than gas boilers. This means they require less energy to do the same job, which offsets the higher price of electricity.
Even better, if you have solar panels installed, you can use the electricity you generate to power your heat pump without relying on the grid.
Is a heat pump more efficient than a gas boiler?
Modern A-rated condensing boilers are more efficient than ever. Estimates suggest that 90% of the energy required to run a gas boiler is used while 10% is wasted. In other words, for every £1 you spend running your gas boiler, 10p is lost.
But when it comes to efficiency, nothing can beat a heat pump.
For every kilowatt of electricity it uses, a heat pump can provide 3 to 4 times as much heat — that’s a 300% to 400% return.
Your house needs to be well insulated to reap the rewards of this efficiency. If it’s not, the heat you’re producing will be lost, and you’ll pay more to run your heat pump as you try to maintain your home’s temperature.
Heat pump vs gas boiler – which is greener?
Gas boilers burn fossil fuels, releasing carbon dioxide and other greenhouse gases into the atmosphere.
By contrast, a heat pump doesn’t burn fossil fuels or emit any toxic gases directly. However, it uses electricity, so indirectly, the heat pump still contributes to the build-up of CO2 emissions.
Arguably, though, electricity is better for the environment than gas.
More than 54% of the UK’s electricity comes from zero-carbon sources (40% of that from renewable sources). So, in the battle between heat pump and gas boiler, the heat pump is the greener option.
Installation and upfront costs
Installing a heat pump is much more involved than replacing a boiler, so it’s likely to take longer. Fewer heating engineers are trained to fit heat pumps, so if your local firm is booked up, you could be in for a bit of a wait.
Ground source heat pumps take longer to install because they require excavation work to fit the pump.
A straightforward boiler replacement (swapping like for like) costs around £3,700. The exact cost of a new boiler installation is determined by the boiler type and size and where in the UK you live.
In contrast, an air source heat pump costs upwards of £10,000, while ground source heat pumps can be as much as £25k+.
To encourage more people to consider swapping their gas boilers, the government is offering up to £7,500 towards the cost of installing a heat pump as part of the boiler upgrade scheme (BUS) for UK properties.
You can find out if you’re eligible on the government website.
Heat pump vs boilers – what else is there to consider?
So far, we’ve considered running costs, efficiency, environmental impact, and installation – but there’s more.
Here are a few other things to consider before you make your decision:
- Heat pumps require more room than a boiler. To install a ground-source heat pump, you’ll need access to enough land near your home for the ground loop system (be prepared for some excavation work).
- Heat pumps have a low flow temperature (the temperature of the water as it leaves the heating system) designed to provide steady heat over the long term, so you may need bigger radiators.
- If you’re switching from a condensing boiler to a heat pump, you’ll also need a hot water cylinder.
Like a gas boiler, heat pumps require regular servicing.
A well-maintained boiler typically lasts between 10 and 15 years, while a heat pump can last between 15 and 20 years (or longer with proper care). Servicing is crucial for maintaining the warranty on either system.
Which is better – a heat pump or gas boiler?
Ultimately, your budget and available space will play a big part in deciding between a heat pump and a gas boiler. In some cases, a heat pump isn’t a viable option – either because you don’t have the room or your house is poorly insulated, preventing you from reaping the benefits of any cost savings.
If your motivation for switching is financially focused, then we recommend speaking to a professional heating engineer first who can ensure your home is set up to enjoy the cost benefits.
For carbon-conscious homeowners who want to reduce their environmental impact, a heat pump is the greener choice.
