Little Penstraze

Little Penstraze front aspect annex and main house

Ground source review: Little Penstraze

John and Sally Berriman chose a 13kW Kensa Evo ground source heat pump to provide heating and hot water for their new build cottage and adjoining annexe building at Little Penstraze in Cornwall. As the heat pump was manufactured just four miles down the road, this renewable heating project has a very small carbon footprint!

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Ground source review: Little Penstraze, Chacewater

John Berriman is a semi-retired Cornish preacher, who has spent most of his professional career working in the dairy industry. Along with his wife, Sally, he purchased a plot in rural Chacewater, Cornwall, on which they built a modern new home for themselves and Sally’s elderly parents. The sizeable plot has seven acres, including five fields. When the Berrimans’ purchased it, it was also home to several dilapidated buildings, the largest of which was knocked down to make room for the new structure.


John and Sally knew that they wanted to use ground source heat pump technology early on in the project. Large areas of Cornwall are off-gas, and as the new build is in a rural location their alternative options would have been limited to oil or LPG, which would potentially have been expensive. The site lent itself to ground source heat pumps, as there is plenty of exposed land area underneath the adjoining field, where slinkies could be located. A local Cornish company performed the groundworks, digging the shallow trenches required for 3 x 50m of coiled slinky pipe.


The Berriman’s knew of a local ground source heat pump installer through a family connection. Edward Savage of EPS Plumbing and Heating is an experienced installer and Kensa partner, having worked on a number of projects installing Kensa ground source heat pump technology. Ed liaised with Kensa, who specified a 13kW Evo heat pump to satisfy the heating and hot water demand for the two dwellings.


The Evo is the newest addition to Kensa’s product range, with a highly efficient output and industry-leading noise reduction. The ground source heat pump travelled just four miles up the road from Kensa’s specialist manufacturing facility on Mount Wellington Mine to the Berriman’s new home in Little Penstraze, Chacewater. The heat pump is housed in the utility room that links the two dwellings.


Building work was completed in under a year with John acting as project manager. The couple lived in a static caravan on site whilst the build was taking place. The two storey new build property is made up of two dwellings; a larger main cottage where John and Sally live, and an annexe which is home to Sally’s elderly parents.


As the two dwellings at Little Penstraze share one EPC, the project is eligible for funding from the Domestic Renewable Heat Incentive scheme (RHI: this scheme has now closed – please visit this page to explore other funding).  This entitles the Berriman’s to guaranteed payments from the Government for seven years to offset the cost of installing the ground source heat pump system.


Both properties were built to a high specification and John was keen to ensure they were well insulated with loft and cavity wall insulation to minimise heat losses. The couple chose underfloor heating throughout the ground floor and radiators upstairs, a combination which works well with the low flow temperature of the ground source heat pump.


John said:


The ground source heat pump has been up and running for a few months giving us lots of hot water, so we’re very happy with it.


The heat pump is in the utility room that links the cottage and the annexe. Ed did a brilliant job of installing it – the pipework is very neat and tidy, and the Evo is smart and modern-looking.


The utility room happens to be underneath our bedroom, but we’ve never been able to hear the heat pump when it’s been running, which just goes to show how quiet it is!

Key Facts

  • Knock down and rebuild project
  • 300m2 property, comprising a 4-bed cottage and 2-bed annexe
  • 13kW Kensa Evo ground source heat pump
  • Heat pump installed just 4 miles from manufacturing site
  • 3 x 50m slinkies under adjacent field
  • Eligible for Domestic RHI (this scheme has now closed)