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Rural stone schoolhouse

Ground Source Heat Pump Case Study
Rural stone schoolhouse

Rural stone schoolhouse

High in the hills of the Yorkshire Dales, above Ilkley, is a rural stone schoolhouse. Built in the 1900’s, this traditional property is owned by Adam Clark, a practicing Architect who specialises in low energy and Passivhaus projects. The property has been cleverly renovated with heavyweight construction to act as a heat store and extensions built and designed using modern construction methods to match the age of the existing property. The final goal of the schoolhouse renovation was to replace the existing natural gas boiler system and install low carbon and renewable energy technologies that would not only decarbonise the property but meet Adam’s sustainability aspirations and assist him in gaining first-hand experience that he can use with his clients and staff.

The Solution

To cover the large site, two NIBE S1155-12kW Ground Source Heat Pumps (GSHPs) were installed in series to provide both space and water heating. The availability of a paddock behind the garage served as a suitable location for the 1000m ground loop array, with the two S-series GSHPs housed remotely in the garage. The hot water is piped to and from the house through underground Rauvithern insulated pipework – removing the bulk of the previous gas boiler system from the main property and placing it in the garage. Alongside the two GSHP units, were installed a 300 litre Megacoil hot water cylinder and a 200 litre NIBE UKV buffer tank, to match the properties space and water heating demands all year round and make the system as energy efficient as possible.

Moreover, to assist in reducing energy bills and utilise renewable energy sources, a 4kW solar PV array was added to the property, further increasing the efficiency of the heating system, future-proofing the household and adding in the ability to sell energy back to the grid during periods of energy surplus. An additional Maximum Power Point Tracking (MPPT) EcoBoost unit was installed to help optimise the system and uses any excess electricity generated by the PV array to heat the hot water, thus, reducing demands on the heat pumps.

The Results

The system, funded through the Domestic Renewable Heat Incentive (RHI) scheme. It has achieved a Seasonal Performance Factor (SPF) of 3.4, due in part to the 1000 linear metres of ground pipework and duel, efficient S-series GSHP plants. It is estimated that annual cost savings will be in the region of £500 at typical energy prices.


“Through recommendation from some friends who had a ground source heat pump installed by Dewsbury based renewable experts Warmaway, we contacted their Director, John Redgwick, who couldn’t have been more helpful and professional.

“With many years experience of ground and air source heat pump installations, their initial survey and calculations were spot on and their original quotation was easy to understand, and split into sensible stages.

“Whilst the installation was carried during late autumn/early winter, complete with torrential rain and snow, the Warmaway team completed the works on schedule, in time for Christmas.

“It was a big moment, when the gas boiler was removed and we switched over to the two NIBE heat pumps, connected to the 1000 linear metres of ground pipework in our adjoining field. The pumps kicked in and they have worked perfectly ever since.

“We have a bountiful supply of hot water and constant heating throughout the winter, with the satisfaction of knowing that we are helping the planet. We now have no fossil fuel appliances with the exception of two wood burning stoves.

“Whilst the recent energy crisis has seen the doubling of our electricity cost per unit, we hope that the efficiency of the NIBE units, coupled with the solar panels and the excellent installation from Warmaway will pay dividends in the long run.”

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