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Electrification of Heat Demonstration Project
Case study

Raj and his family’s air source heat pump

“Having a heat pump installed will help me and my family achieve net zero.”

The project

Funded by the UK Government Department for Business, Energy and Industrial Strategy, the Electrification of Heat Demonstration Project was designed to understand the technical and practical feasibility of a large-scale rollout of heat pumps. Find out more about the project.

Raj and his family were part of the project.

The challenge

For more than a decade now, Raj and his family have been on a journey to reduce their carbon emissions. They have bought an electric car, installed rooftop solar PV, done insulation upgrades and installed smart heating controls. Raj is proud that their energy efficiency has increased significantly and their power demand is totally covered by renewable electricity.

When the family found out about the UK Government funded Electrification of Heat Demonstration Project, which is trialling heat pumps, they felt that replacing their gas boiler was the missing piece in achieving zero carbon emissions and living a fully sustainable life.

In addition to doing the right thing for the environment, Raj was also keen to replace their gas boiler because it was old and unreliable, and the family worried that it could break at any time. They decided to join the Electrification of Heat Demonstration Project to increase their energy efficiency further and get a modern and reliable system providing their heating and hot water.

Solution and benefits

An air source heat pump was installed with the outdoor unit in the family’s back garden and a hot water tank in a cupboard in the kitchen, where their old gas boiler used to be located. Three radiators out of the 15 in their home needed to be replaced with larger ones, but none of the pipework needed to be changed.

Replacing their old gas boiler with a reliable, low carbon heating technology was a key benefit of having a heat pump installed for the family. Raj is happy with how warm his house is and believes that: “Heat pumps are an option absolutely worth exploring for every household.”

Installing the heat pump

How long did it take?

The installation process was completed in a week. The heat pump was installed in less than two days. Fitting the hot water tank in the kitchen cupboard took a few extra days as it required additional plumbing work. There were also some delays getting materials.

What did it involve?

The heat pump outdoor unit was placed in the back garden and the hot water tank in a cupboard in the kitchen, where the gas boiler was previously located. Raj felt that the installers did a brilliant job with the heat pump installation and appreciated their support with the system configuration.

Were they happy with the result?

Raj and his family are very happy with their new heat pump.

Common concerns about heat pumps

Energy costs

At the time this case study was written, the family has only been living with the heat pump for a few months, so it is too soon to say how annual running costs compare to their old gas boiler.

However, Raj has been comparing the monthly running costs and noted that it depends on the relative costs of gas and electricity: “When we first installed the heat pump, the monthly cost was comparable to our previous gas boiler, however with the increased gas prices, the cost of running the heat pump on renewable electricity might become cheaper.”

Disruption in the home

Raj felt that the heat pump installation did not cause any significant disruption in his family’s everyday life. “The installers did a fantastic job. They were professional, on time and they respected our space and home,” Raj said.

He highlighted that the installers did everything they could to ensure that there was minimum disruption to his family’s daily routines. The installers also provided portable heating systems so as not to leave the house without heating at any point during the installation, and the house was only without hot water for just over a day.

Warmth and comfort

Raj and his family are happy with how warm their house is after installing the heat pump. They are particularly pleased with the increase in hot water pressure, as they can now have two showers at the same time. “This has been really convenient for us,” Raj said.

Aesthetics and ‘look’ of the heating unit

“Given the recent press coverage, the heat pump is a great conversation starter with our guests in the kitchen and garden. The heat pump looks very much like an air conditioner unit in the rear garden,” Raj commented.


Raj and his family have had no issues with noise from the heat pump.

Impact assessment

The family’s new heat pump should be over 300% more efficient* than their old gas boiler.

It will reduce their heating carbon dioxide (CO2) emissions by about 80%*. This is equivalent to having three less cars on the road each year.

At the moment it is likely that the heat pump cost more to run than the family’s old gas boiler, depending on which electricity tariff they use. However, the heat pump will become more cost-effective to run in future if levies and obligations are adjusted to make electricity less expensive relative to gas.

*Assumptions: annual heating demand of 25,000kWh; average heat pump SPF of 2.64; gas boiler efficiency of 84%; mains gas carbon emissions 0.21kg CO2e per kWh; electricity carbon emissions of 0.136kg CO2e per kWh; vehicle emissions of 225g CO2e per mile; average driving distance of 7,400 miles per year.

This case study is part of a series produced as part of a UK Government funded project through its Energy Innovation Programme, the Electrification of Heat Demonstration project. The project is trialling different types of heat pumps in up to 750 homes across the UK.

Last updated: 20 July 2022