Domestic Retrofit Ground Source Heat Pump Installation

The Background

A whole house renovation in an old property in Llanfairpwllgwyngyll, on the Isle of Anglesey in North Wales. The owner of this property has capitalised on the benefits of installing a Stiebel Eltron Ground Source Heat Pump system to supply heating and hot water to the 100 year old property.

Owners of Mr & Mrs Winder chose the system as a replacement to its olid system which was costly and required modernising. Annual costs for running an off-grid oil system can be four times as much as a sustainable source and generate at least twice as many CO2 emissions.

This final renovation, by the current owners, included updating the central heating system (radiators) and updating the insulation levels of the property.

Mr. Winder explored renewable heating systems which supported the off-grid nature of his home and his research highlighted the efficiencies of Ground Source Heat Pumps, their capabilities of supplying heat and hot water and their carbon neutral credentials.

Installers JM Renewable Solutions specified and installed the system comprising of Stiebel Eltron 10kW Ground Source unit, with an integrated 200L cylinder and 100 L buffer cylinder. The integrated water cylinder allows for less space to be taken in the plant room, which was very appealing to the Winders as space was restricted.


“Stiebel Ground Source Heat Pumps provided the perfect solution for Matt’s property and would deliver the cost savings he was looking for compared with his antiquated oil boiler system which was estimated at over £1500 per annum,” commented Ben Musgrave Director, JM Renewable Solutions. “The quality of Stiebel products and their reputation for successful installations in rural settings attracted the homeowner to this solution and, as we were familiar with such systems, we were well placed to advise him on everything from equipment requirements to installation procedures and the long term return on investment.”

The project required the installation of a 12kW ground source heat pumps with a 200 litre integrated hot water cylinder and 100 litre buffer cylinder. 800 metres of pipe was laid in the field adjacent to the home which, whilst labour intensive, generated the required heat so that they could enjoy ambient temperatures throughout the day and night rather than limiting the use of their previous system due to escalating and unsustainable costs.

The Ground Source Heat Pump System works through a buried pipe system laid 1.2 metres below the surface which extracts heat from the ground to provide efficient and reliable heating and hot water. It circulates a mixture of water and antifreeze around a ground loop. The heat is absorbed into the fluid which then passes through a heat exchanger and into a heat pump. Because the ground stays at a remarkably consistent temperature below the surface, and is not affected by weather conditions heat pumps can be used successfully throughout the year.


The system was designed and installed by Stiebel Installer, JM Renewable Solutions, whose experience in this field allowed for a seamless system installation right from site survey, through to commissioning and ongoing maintenance support.

The 12KW ground source heat pump fitted nicely at the property and is an ideal solution for this retro-fit situation and the land surrounding the property was perfect to accommodate the ground loop pipe required.

This particular pump is enjoying a A**energy rating. Furthermore, the range is installer and user friendly and can offer indoor comfort and hot water as well as cooling and ventilation. The Winders will benefit from a 50% decrease in their annual heating bill and will enjoy approximately £2000-2500.00 p/a from the domestic RHI.