Case study: Llanishen House

Formerly a Medieval inn, Llanishen House situated in the Monmouthshire countryside has two Kensa ground source heat pumps installed; a 24kW Twin in the expertly renovated main house; and a 9kW Evo for the soon-to-be converted granary. The first heat pump system uses coiled slinky pipes, whilst the second uses boreholes to maximise the remaining available land.

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Renovating the main house

Llanishen House, overlooking the Usk Valley in picturesque Monmouthshire, was formerly the site of an old inn parts of which date back some 600 years. Its owner Richard Waterstone has carried out a full renovation of the main building to create a modern and spacious family home with heating and hot water provided by a Kensa ground source heat pump. He is currently undertaking a project to convert the old granary building into a luxury 3-4 bedroom property for which he is using a second Kensa ground source heat pump.

Due to its rural location the site is off the gas grid and oil was not an option that Richard wanted to use. He explained:

I can’t bear the stuff – it’s so environmentally unfriendly. Plus it comes with the nuisance of organising deliveries and storing the fuel. I believe in using more sustainable technology and wanted to generate my own power.”

To this end, he had a Kensa 24kW Twin installed in 2015 to provide heating and hot water to the main house, and is extremely happy with it. Richard was already familiar with ground source heat pump technology, as a friend of his had had a heat pump installed by Kensa into a property in Scotland.

Richard said:

I love the technology – the idea of harnessing free heat from the ground is so simple and Kensa’s kit is top of the range. I often show visitors our heat pump unit and they are blown away by the efficiency and simplicity of our heating system. I’m really pleased with how it’s working.”

Llanishen House is a large 500+m² property; Richard’s refurbishment having incorporated an internal courtyard into the building. As such, the demand for heat was high – ideally suited to Kensa’s Twin Compact heat pump which is fitted with two internal compressors. The heat pump unit is housed in the spacious cellar – a legacy from when the property used to be an old inn. Richard enjoys taking people down to show them the high tech kit!

The original building was part Medieval and part Victorian with some solid sandstone walls, and prior to the refurbishment project it was cold and draughty. Richard converted it to a very high specification incorporating modern features with traditional styling in keeping with the property’s history. He included double glazed windows and wall insulation to lessen the property’s heat losses.

The house has mostly underfloor heating throughout which increases the efficiency of the ground source heat pump. Richard says:

I would definitely advise other people thinking of installing a ground source heat pump to pair it with underfloor heating. It saves replacing radiators, and is more design friendly, removing pipework and freeing up space in rooms.”

The heat pump extracts energy from the ground using 300m of coiled slinky pipe which is located underneath two horse paddocks. Richard had the slinky trenches dug with the help of a local digger.

He said:

I was initially worried about the upheaval as the trenches were being dug, but I was astonished when they were filled back in, because you would hardly know that the pipes were under there, especially when the grass was sown!”

Richard oversaw the installation of the heat pump, supported by Kensa’s MCS Umbrella scheme. Under the scheme, Kensa takes responsibility for the sizing, specification, appropriate quotation, commissioning and MCS registration of the ground source heat pump system.

Richard commented:

Throughout the project I had lots of help from Kensa and was very pleased with the service I received.”

Richard has covered the cost of the ground source heat pump installation via the Government’s Domestic Renewable Heat Incentive (RHI) scheme which provides quarterly payments on the renewable heat the system generates. Llanishen House also features other renewable technologies, including Solar PV on the roof to generate electricity for which Richard is receiving subsidies.

 

Converting the granary

In 2017, Richard decided to renovate the granary, a separate building on the site. It was falling down, the timber cladding and steel frame having rotted and degraded. It features a three storey stone tower, the top floor of which Richard has had to leave as a roost for the bats that live there. The building also has a lean-to which Richard suspects may have housed a steam engine that powered a conveyor belt for the grain.

Richard intends to turn the granary into a 3-4 bedroom house that eventually his family will move into. Again, he is working to a very high specification on the build, for example using sustainable vertical hit and miss timber cladding on the new-build section.

Based on the performance of his first ground source heat pump and the great customer service he recived, Richard decided to approach Kensa again. He did this early on in the build so he could incorporate the heat pump installation at a convenient time in the renovation. The ground source heat pump will harness energy from the ground via two 200m boreholes, maximising available land and minimising disruption.

For this project, Kensa was pleased to be able to specify a 9kW heat pump from the brand new Evo Series launched in spring 2017.  Perfect for larger builds and renovation projects, the Evo is capable of heating domestic hot water to 60°C and boasts industry leading noise reduction. It also offers a 15% gain in efficiency over previous models, minimising running costs and maximising income via the RHI.  Richard’s heat pump is expected to be installed in September/October 2017.

Richard said:

Throughout this project I have worked hard to source the highest quality products from around the world – I have wood from Siberia, kitchen fittings from France – so it’s wonderful to be able to include a British manufactured Kensa heat pump in that list.”

For more information, see https://www.kensaheatpumps.com/product/7-15kw-evo-heat-pump-series/

Key Facts

  • Part Medieval, part Victorian and part new-build
  • Renovated inn and granary building
  • 24kW Twin in main house
  • Supplied by 300m of slinky pipes under a paddock
  • 9kW Evo in granary
  • Supplied by two 200m boreholes
  • Both systems eligible for the Renewable Heat Incentive (RHI)