The idea of using sheep wool to insulate your house didn’t seem very revolutionary to me when I started reading about it in the papers. Surely, we’ve been using wool in our houses for centuries? Apparently not the idea of insulating homes against heat loss is relatively new. Houses were designed to keep off the wind and the rain. Humans insulated themselves with thick clothes, rather than going to the extravagance of lining their homes. Wool was the first choice for this, but it seems there wasn’t much wool left over once everyone was properly dressed. This, of course, is all changing.

Living in an uninsulated house has now become one of the worst financial, not to mention social, omissions in this climate-changing world. Smart Greens are no longer only discussing how much to insulate; now, the big question is synthetic or natural? Meanwhile, demand for wool is falling particularly for tougher, lower-grade fleeces from hill sheep. The surplus allows us to contemplate spreading rolls of the stuff through our roof spaces.

This growing interest has prompted a group of old hands in the construction industry to build Britain’s first dedicated natural insulation factory in North Wales where else? Black Mountain Insulation has just started converting bales of British fleeces into lovely woven material thick enough to sleep on. Chief executive Andrew Evans had been selling plumbing before he realised that insulation was going to be the next big thing as environmental concerns hit the building industry. After initial excitement when he discovered natural wool products on the market, he was disappointed to learn how expensive they were compared with their synthetic equiva-lents. He realised that, unless he started making the material himself, wool insulation was only ever going to be used by a committed minority, such as the National Trust.

In spite of Mr Evans’ efforts, wool is still more expensive than its main synthetic rivals, but the natural lobby argue that it’s better value. It certainly seems to tick most environmental boxes. Its competitors may be good for the planet once installed, but making fleece from glass or rock uses a lot more energy than shearing it from a sheep. Indeed, if you factor in all of the grass that goes into feeding the sheep, wool insulation has a negative carbon footprint. Further-more, this new use will provide a much needed boost to beleaguered hill farmers. Dai Davies, president of NFU Cymru, said that they have recently been getting as little as 20p a fleece, which is pitiful, particularly as it costs £1 to shear a sheep.

Beyond its environmental advantages, wool insulation still has a bit of a way to go if it’s going to justify its higher cost to the sceptics. Its advocates point out that it should last and be effective forever if properly installed. A simple natural insecticide prevents it being eaten, and it even absorbs and locks in the unwelcome chemicals that tend to float around our houses these days.

Most interesting is that it can regulate moisture in the home. It behaves just as it did when protecting the sheep. Absorbed moisture heats it up and, as it dries, it cools down a perfect, natural air conditioner. Even in these hard times, paying a bit extra to line your home in British wool may just be the investment you won’t regret.

Black Mountain Insulation, Denbighshire (01745 361911; www.blackmountain-insulation.com). Second Nature UK, Penrith, Cumbria (01768 486285; www.secondnatureuk.com) Until May 1, COUNTRY LIFE readers can claim 10% off any wool-insulation orders from Black Mountain Insulation by quoting COUNTRY LIFE offer