Russell and Helen Keenan, and their four children, moved to Saughall in Wirral about 6 years ago.

“I think it was then,” Russell explains, “when we moved to the countryside, that we really started to think more carefully about the environment and our impact upon it.”

A year ago, the family began their massive project to build a self-sufficient zero-impact home with an adjoining holiday house. Beginning with very little knowledge of building, a long period of research preceded the start of construction in September 2006.

Since then, they’ve been filmed by the BBC for It’s Not Easy Being Green, joined in the project by scores of intrigued volunteers and have also become the talk of their local village.

“Most people are really interested in what we’re doing up here, but yeah, you do get some funny looks,” Helen jokes.

Russell’s a paediatrician by day, allowing only the evenings and weekends for building, yet he is still boundlessly enthusiastic more than a year into the project.

“Our aim is to be entirely self-sufficient on energy, water and sewage,” he explains. “Basically the house is being built with two principles. One, it will be built to last, which in itself is low impact. Most modern houses are only built to last 50 years, but this is being built to last 500 years. And the second is that we will use natural, renewable, low energy materials as much as possible.”

The Keenans, who previously lived in a crumbling bungalow in the corner of the site, are using a number of unique materials and techniques in their attempt to avoid conventional, energy-intensive methods. For example, instead of cement, which requires a high energy manufacturing process, green oak is used and the wood is air-dried, not kiln-dried. The plastering is prepared with lime, instead of the more conventional and environmentally damaging gypsum. As lime does not bind as easily as cement, hair from their pet goat doubles as fibreglass in the plaster mix. Also, lime plaster, as Russell informs me with the wonder of a schoolchild, actually absorbs carbon dioxide. The roof is covered with natural slate and the floor is made of sliced stone tiles.

These materials and techniques have all been discovered through internet searches and visiting various facilities, such as the Centre for Alternative Technology, for advice. Not long ago, Russell and Helen’s understanding of low energy building techniques was non-existent. On site, their dedication to the project is visible as every detail of construction contains evidence of their research.

Of course, many of the materials used are rare and, therefore, more costly than standard building materials.

“No doubt that some of the green choices are more expensive, but we’re doing cheaper things in the long run,” says Helen. “A green lifestyle is less waste, which means less cost.”

Here Helen is alluding, not only to the fact that all of their furniture is second hand, procured from local Freecycle groups, but also to the technology that allows the family to live in a zero impact home. The Keenans source all their electricity from a wind turbine, a large reed bed takes care of the sewage, the rooms are heated by ground source heat pumps and their water is harvested from the rain. There’s no shortage of wind or rain on the Wirral coastline, which means the Keenans shouldn’t have much trouble maintaining their water and energy supplies.

The project would be bold enough without considering that Russell and Helen also have four young children to look after. But as Helen points out, having children only underlines the importance of the project.

“Of course, having four kids on site doesn’t make things any easier,” says Helen. “But what we’re trying to do is create a family home. We’re trying to build a future for the kids, and a sustainable future is obviously part of that.”

The young Keenans aren’t the only ones on site as the family regularly play host to volunteers, who have learned of the build through a website called HelpExchange. Volunteers from all over the world have stayed in a tippi located near their small lake for up to six months to help build the house and holiday suites. The complex even includes a swimming pool for the future holiday-makers, heated, of course, by the ground source heat pumps.

The family are currently living in a small completed section of the home, which should be finished, along with the holiday home and their small lake house – ideal for fishing – by summer ’08. And Russell hopes that the Keenan’s outlook might have an effect on any visitors to the holiday home.

“People can come here and see that you can have a comfortable lifestyle, a holiday in luxury, with zero impact,” he says. “That will, hopefully, make people think a little differently when they leave.”

Gavin Thomson is a journalist and lives in London.