Skip to main content
Press Release 29 February 2024 Updated 6 March 2024

Cut through the hot air: four heat pump questions clarified

Energy Saving Trust launches new campaign to help people make the switch to low carbon heating.

New government data released today shows that installations of heat pumps are on the rise in England and Wales1. However, the pace is still slower than what’s needed to achieve net zero targets of 600,000 installations a year by 2028. To help drive further uptake, Energy Saving Trust has launched a new campaign, ‘Cut through the hot air’.

The campaign will cut through the myths and clarify the facts around installing a heat pump for homeowners considering them as a low carbon heating option.

Brian Horne, technical knowledge lead at Energy Saving Trust said:

“In the UK’s transition to net zero, heat pumps are key to reducing carbon emissions from heating our homes. In fact, a semi-detached home with an older, G-rated gas boiler would save around 2,900kg of carbon dioxide emissions a year by replacing it with an air source heat pump, the equivalent of flying from Belfast to Nairobi and back2.

“While more people are installing heat pumps, this needs to be much faster. Our new campaign aims to help build confidence about making the switch by clarifying the facts so that people can make a better-informed decision about what’s right for them.”

1: Will I have to install more insulation before installing a heat pump?

Installing more insulation in walls and roofs isn’t necessary for having a heat pump – they still work well in homes with less insulation. However, a recent poll carried out by YouGov on behalf of Energy Saving Trust shows that only 29% of Brits know this3.

To qualify for a government grant towards installing a heat pump your home must have a valid Energy Performance Certificate (EPC) with no outstanding recommendations for cavity wall or loft insulation, or evidence to show why these measures aren’t possible.

If you aren’t able to top up your home’s insulation, a heat pump system could still be designed to work well in your home depending on your heating needs and property type. This may involve installing larger radiators and programming your heat pump to come on at the optimal times to get your home up to the right temperature.

2: Will it require a lot of maintenance?

Heat pumps require no more maintenance than a gas boiler, although the recent polling shows that only 25% of people know this3. They require an annual check, often as part of their warranty, to make sure the system is clean and working efficiently.

One of the differences is that if a boiler isn’t serviced it will become less efficient over time, whereas the efficiency of a heat pump changes based on the weather, or if it’s not kept clean.

All heat pump installers and some manufacturers will offer servicing packages. An installer will also supply a list of regular checks you should undertake to ensure everything is working properly.

3: Will I have enough room?

Air source heat pumps, which have an external unit fitted close to a property, are the most common system installed in the UK and are suitable for many types of home. They are about 1 metre tall and 1.5 metres wide. This means they take up no more space than two garden waste wheelie bins – although our recent polling shows that only 29% of people know this3.

Inside your home, you’ll need a hot water cylinder to store hot water for when you need it. This can usually fit in a cupboard that’s around 80x80cm. For smaller properties where space is limited, smaller hot water storage solutions have also been developed.

4: Will I be able to afford it?

The UK Government offers financial help towards replacing a fossil fuel heating system with a heat pump, however our recent poll shows that only 50% of people are aware of this3. Although they currently tend to cost more to install than the average boiler, the grants of up to £7,500 on offer under the Boiler Upgrade Scheme4 can help to significantly reduce the initial outlay.

Once installed a heat pump would be expected to cost a similar amount to run than the average gas boiler. If you’re replacing an older, G-rated gas boiler, you could even save around £340 a year on your energy bills under current energy prices5.

However, it’s important to note that households replacing a newer, efficient gas boiler won’t yet make significant energy bill savings by fitting a heat pump.

Well-designed heat pump systems will have the lowest running costs, so when designing your system, your installer may recommend installing larger radiators to allow your heat pump to work as efficiently as possible.

Energy Saving Trust’s campaign runs across digital channels from 26 February to 31 March and aims to provide reassurance and clarity around common barriers to installing a heat pump.

For more information visit:



[2] Based on airplane emissions ranging from 0.154 to 0.246 kg/CO2e/km on a per passenger basis, not the entire aircraft.

[3] The survey was carried out by YouGov between 29-30 January 2024, surveying 1,000 people across Great Britain.


[5] Figures are based on energy prices as of January 2024. The running cost you can expect will depend on the size of your home, any heating system upgrade and any saving will also depend on the fuel type and age of the heating system being replaced.

Find out more about how Energy Saving Trust made these calculations.

Last updated: 6 March 2024