Installing an air source heat pump to improve the eco-credentials of a home

December 16, 2022
4 min read

Customer case study: How one Oxford homeowner made the switch from oil-based heating to an air source heat pump

At Green Building Renewables, we’re committed to helping homeowners and businesses find more sustainable ways of generating their energy so that they can move away from traditional fossil fuel-based sources and save on their energy bills.

For all our customers, there’s a range of factors to consider such as space, affordability and the long term return of investment from sustainable energy.

Our client Violet’s ambition was to make her Oxfordshire home as eco-friendly as possible, particularly as she had already invested in solar panels. The next phase of her renewable energy mission was to replace oil-fired heating with either an air source or ground source heat pump.

After reviewing the pros and cons of air source or ground source heat pumps, the latter proved too expensive. So, we helped Violet explore a range of air source heat pumps based on an assessment of her heating requirements and the size of her property.

“Our top priority when we moved house was to make it as environmental as possible to run. We got a couple of quotes for ground source heating, but we found it unaffordable for us – we were unsure if our house was suitable for an air source heat pump, but then a specialist electrician recommended GBR, so we gave them a call.”


If space is at a premium, then an air source heat pump is the obvious way forward, as these can be mounted on the wall or the ground.

We have several air source heat pumps that we can specify. For Violet, we recommended the Daikin Altherma 3 High Temperature 16kW ASHP air source heat pump, supplemented by the Daikin unvented 250L hot water cylinder. Given the large size of her property, she needed an air source heat pump solution that could support high efficiency radiators. These replaced eleven single and double fin radiators, allowing us to optimise the heat pump’s performance.

Unlike ground source air pumps, air source heat pumps are a far less invasive installation. The Daikin heat source pump was installed at the side of the property, with the cylinder installed in the kitchen.

Violet is now receiving the RHI (Renewable Heat Incentive), which sees her receive quarterly payments over seven years. This has now been replaced by the £5,000 Boiler Upgrade Scheme (BUS) grant, for which Green Building Renewables are approved installers. This means we can also help you with your application as well as the actual installation.

Green Building Renewables Air Source Heat Pump Oxfordshire
Green Building Renewables Air Source Heat Pump Oxfordshire

How do air source heat pumps work?

Air source heat pumps extract heat from the outside air by converting low grade heat into usable energy. It does this by passing the air through a compressor, increasing its temperature. Amazingly, air source heat pumps can work with outside temperatures as low as -20℃. Even at these lower temperatures, the Coefficient of performance is still 340%, on average, despite fluctuating outside temperatures.

How efficient are air source heat pumps?

Air source heat pumps are very energy efficient, converting 1 Kilowatt of electricity into 340 kilowatts, making them 340% efficient. By comparison, an A-rated combination boiler can only convert 1 kilowatt of electricity into 0.9 kilowatts of electricity, making it 90% efficient.

How much money can I save by installing an air source heat pump?

There are several variables we need to consider before arriving at an answer. So, the amount of money you can save will depend on the size of your property, how well insulated it is, the size of your current radiator system and whether you have underfloor heating. Each property is unique, and if you’re like Violet, and already have solar panels, you can use this free energy to power your heat pump.

‘They were very friendly, thorough and professional throughout, providing an extremely high level of service. We would highly recommend GBR to anyone wanting to improve the environmental impact of their home or business.

What did Violet think of her experience with Green Building Renewables?

“We would recommend having one installed, and we have recommended it to family members and several of our friends. GBR were very friendly, thorough and professional throughout, providing an extremely high level of service. We would highly recommended GBR to anyone wanting improve the environmental impact of their home or business’


Still need convincing? Such is the attractiveness of air source heat pumps that there are government incentives to attract people to go down this route. And last week, it was reported that Barclays is now encouraging homeowners with a £2,000 incentive to install heat pumps.

Barclays to pay borrowers £2,000 to install heat pumps (

Interested in an air source heat pump? Launch our air source heat pump calculator to learn more

Written By:

Sarah Taylor, Group Project Support Manager
Sarah Taylor
Sarah’s experience predates the formation of Green Building Renewables. She was a critical member of the management team that rebranded to GBR. It was the allure of a new challenge and the chance to make a difference in a family business which propelled her entry into Green Building Renewables during a dynamic phase in the industry. Want to know more about Sarah? Click here to find out more : Read More

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