Case Study

Part 1/3: Heat pumps key to energy efficiency in retrofit project

In order to achieve a net zero carbon status, multi-tech solutions consisting of air source heat pump units and PV panels were used during a retrofit of a primary school in Gloucestershire.

This first of three posts in our retrofitting mini-series showcases the project, highlighting what you need to know about retrofitting using renewable technologies.

St Andrews CofE Primary School, in Chedworth, worked with plumbing and heating engineers C.P. Jefferies to achieve their ambitions of a having a low cost and renewable heating system which could maintain a comfortable temperature throughout the school, while being as energy-efficient and carbon-neutral as possible. Completed in March this year, it is a perfect example of a successful retrofitting project that was able to meet the needs of an educational institution whilst achieving its net zero carbon status. So, how was it achieved?

The project, which was managed by Inspired Efficiency who helped the school to obtain a £120,000 grant through the Governments Public Sector Decarbonisation Scheme administered through SALIX, overcame a number of challenges, including delays in funding being released, complex planning approval and undertaking site safety working practices to safeguard against the risks posed by Covid-19.

However, by replacing an old oil boiler and installing PV panels, LED lighting and four Mitsubishi Electric 14kW R32 Ecodan air source heat pump units – that were able to keep a consistent temperature across 3 heating zones in the school all year round – the school achieved its net zero carbon status.

CP Jefferies found the Ecodan system straightforward to install, meaning the four units can work in a cascade so that they share the workload evenly and are easily able to match the heating demand. This means that the life of each unit can be prolonged, whilst minimising the amount of power consumed, thereby keeping costs to a minimum for the school. What’s more, because Inspired Efficiency were able to apply for the funding under the Salix scheme, this made Ecodan a straightforward choice for the school as they were able to remove an antiquated oil boiler and replace it with modern air source heat pumps.

St Andrews school now can meet its residual energy demand through a 100% renewable electricity supplier and estimates it will save 15.49 tonnes of CO2e per year and financial savings of £4,500 per year.

According to the headteacher Nikita Smith, the pupils are well aware of climate change, so they were excited to know their school were getting rid of the oil boiler and embracing renewable heating. For the school, it means they can significantly lower their heating bills and carbon footprint and they no longer have to worry about winter deliveries.

To conclude, the retrofitting of public buildings and especially schools are complex, with many challenges to overcome. But with the right installers conducting detailed assessments of the site and understanding the nuances of the education sector, the best partners with a detailed knowledge of the funding available, and the most eco-friendly solutions – huge carbon efficiency and cost benefits can be achieved.

Max Halliwell, communications manager, residential heating, Mitsubishi Electric & vice chairman of the UK’s Heat Pumps Association shares his views on what installers need to know about retrofitting, especially when taking on a project like this, in our mini-series. Find part 2 here.