An historic property on a nature reserve where one of Britain’s most endangered animals’ lives has been brought into the 21st century thanks to a sophisticated underground heating system.

The stone farmhouse of Penllyn lies on Cors Goch National Nature Reserve where the rare water vole – the Water Rat of Kenneth Graham’s children’s classic The Wind In The Willows – is still found.

It was once common on the UK’s rivers, lakes and streams until habitat loss and the depredations of the American mink caused a 90 per cent fall in its population in the last 40 years but Cors Goch remains a stronghold.

The North Wales Wildlife Trust reserve also contains rare orchid species, is a hunting and nesting area for barn owls and home to fenland birds like the sedge warbler as well as adders and great crested newts.

Penllyn lies in the heart of the reserve and without access to mains gas which meant a ground-source heating system was an ideal solution but with so much of the nearby land peat bog and wetland the solution was to go deep, according to David Jones, managing director of ‘green’ energy experts Hafod Renewables.

They called in Dragon Drilling, of Ruthin, to drill three boreholes each over 270 feet deep but only eight inches in diameter before laying pipes for an advanced ground source heating system.

Down that deep the bedrock is at a constant 12 degrees Celsius and a heat exchanger does the rest, raising that temperature to a perfect 22C in the house with water heated to 60C.

That water supply is also improved as a result of the work with a new borehole replacing the old spring-fed system.

David Jones, Managing Director of Hafod Renewables, said: “Penllyn is a lovely old farm cottage but it really needed an effective heating system in such a potentially damp area and this is what it now has.

“We recommended ground source because it is cheap, efficient and easy to run, it fits with the Trust’s ethos and it’s also half the price of oil and a third of the cost of electric and the heat exchanger system is now housed in the farm’s kitchen.

“It uses the big bank of heat that exists deep down underground and while the Trust’s new tenant gets a really good heating system the Trust itself will now bank a £4,000 Renewable Heat Incentive annually for seven years which will more than pay for the installation cost.”

Frances Cattanach, Chief Executive of the North Wales Wildlife Trust, based in Bangor, said: “This is an internationally important site and as we are an environmental organisation we wanted to reduce our impact on climate change by considering a renewable energy system.

“Cors Goch is a massive carbon sink – it’s a lake which is gradually filling in and a fantastic resource for storing carbon.

“Penllyn is a Grade Two listed building which dates from the 1890s and it has hay meadows which we still manage.

“The drilling down into the bedrock was done very carefully because Cors Goch is a wetland site and its water supply is critical.

“This area of Anglesey is particularly special because of the geology, which creates a calcium-rich wetland because of the limestone. These fens are very rare, and support great fen sedge which used to be cut to put on top of hay ricks to keep them dry.”

Hafod Renewables, based on Denbigh’s Colomendy Industrial Estate, was founded eight years ago by former Holywell High School pupil David, an electrician and graduate in Renewable Energy and his father, Richard, a heating engineer, when the solar industry, fuelled by a generous feed-in tariff, was booming.

A Government cut to that tariff drove many firms out of the business but Hafod, which employs nine staff, has continued to grow as the company has expanded into other areas such as ground and air-source heat pumps, biomass and underfloor heating and these now account for more than 60 per cent of their business.

For more on Hafod Renewables go to and for more on the North Wales Wildlife Trust go to