LIVING underground without heating may not be everyone's idea of a dream home.

But for Helen and Chris Seymour-Smith it is the culmination of hard work and meticulous planning.

Millions of viewers saw the green scheme come to life on Channel 4's Grand Designs – from a giant hole in the middle of the Cotswolds countryside to a state-of-the-art hidden home.

Built under the ruins of a 300-year-old barn, married architects Helen and Chris wanted it to be England's first accredited "passive" house – airtight and needing no heating – built to German Passivhaus eco standards.

"It was a no-brainer when we came to building a new house," Helen said.

"We believe strongly it's the best way of achieving a desperately-needed reduction in carbon emissions.

"We'll expect to be making more electricity than we use."

TV presenter Kevin McCloud worried the cavernous and minimalistic house could feel a bit cold and industrial. But the creative couple decided to dig deep because their design would not have got planning permission if it had been visible in the Cotswolds Area of Outstanding Natural Beauty, four miles from Moreton-in-Marsh.

They used a planning law which allows a house of exemplary architectural merit to be built in open countryside.

"We wanted to build something crisp, modern and white and very un-Cotswolds," said Helen.

"Building a subterranean house is a method that's allowed us to do that in the landscape we enjoy."

The deeply-rooted home is blanketed with high-tech insulation and soil.

It features solar panels and a row of south facing triple-glazing on to a courtyard.

Helen said: "It's an absolute joy not having the view, so that every time we come out we just say 'wow'."