If you reckon you have to be a member of the brown-rice-and-sandals brigade to live in an eco-home, then Kester and Zinnia Wilkinson beg to differ. The Herefordshire couple may be one of only a few in the country to live in a straw-walled house, but that was not what they intended when they first began hunting for a home.

“We’re accidental environmentalists,” admits Kester, 35, a manager at a learning resource centre. “When we set out to build our own home it was to save money, not the planet.”

The Wilkinsons did not like the look of any of the three-bedroom homes for sale within their budget in the Ledbury area and stumbled across the idea of self-building in 2000, when they read a book on the subject. From then, the couple, and their daughters India and Liberty, now aged eight and six, were on the road to building their own home — but with an eco-twist.

“I was researching building materials when I was recommended to go on a straw bale course,” says Kester. “Then people kept coming up to me saying there were more environmentally friendly ways of doing other things. They introduced me to materials such as lime and breathable paint. Before that, I’d been into things like chipboard.”

Their two-storey property, finished in mid-2002, is timber-framed and has foundations filled with vermiculite, a sponge-like mineral that provides extra insulation. The walls are made of straw covered in clay, with a plaster finish, and the roof is shingle-covered.

The Wilkinsons spent £100,000 buying the land and knocking down a 50-year-old bungalow that was on it, and then another £70,000 building the house — £20,000 more than planned.

“But it’s a false economy to hold back on eco-products,” says Kester. “Using breathable paint at £6 a litre, for example, sounds expensive. But it requires only one coat and stays in good condition longer than conventional paint. The long-term approach means your running costs can be much lower.”

Zinnia, 36, a primary school teacher, masterminded the interior, which is painted and colourwashed with Keim, a hard-wearing mineral paint, and bought a beech tree from a local tree surgeon to provide the wood for the stairs and windowsills.

The Wilkinsons believe the evidence proves that eco-friendly features are cheaper as well as kinder to the planet.

“Last year, we bought a solar panel. I was a bit wary of having it on the roof and doubted it would really be efficient in the British climate,” admits Kester.

His scepticism was overturned, however, when the family discovered the panel generated enough heat to keep their water at 36C even under the leaden January skies, and reduce hot water bills by about 10%. They now spend only about £240 a year on hot water and heating for their 2,152sq ft family home.

“What puzzles me is why developers don’t take notice of the experience of people like us. They don’t even bother putting in improved insulation. That alone would improve a property’s eco-rating and save money for the owners, as we’ve proven,” says Kester.

Four years on, the Wilkinsons have nothing but praise for the lifestyle generated by their home.There were mistakes, of course: Kester says that not using an architect backfired when ordering materials and relying on drawings that had inaccurate measurements. Failure to hire scaffolding for the roof slowed progress when he and Zinnia were at their most tired after months of work.

Using eco-materials has proven cheaper than expected in the long term, he says, while the positioning of the windows to take advantage of the sun to maximise natural warmth and light has been a success.

The property was valued at £200,000 when it was completed, giving the family a notional £30,000 profit in return for 10 months of hard labour.

Although it has appreciated further since 2002, the Wilkinsons have been told that had they built the property in a conventional fashion using mainstream materials, it might have been valued at up to twice as much.

Yet, as Zinnia puts it: “I can’t say if it is better or worse, cheaper or warmer, longer-lasting or greener — but it is the house we wanted and we love it.”

Times recommends

• Second homes: credit crunch casualty or money-spinner?
• How I built my own sliding house
• Top 10 incentives for house buyers