Insulate your house with sheep

No, I'm not suggesting you use actual sheep to insulate your loft. That'd be be impractical, not to mention morally dubious. I'm referring to Thermafleece, a new insulation material made from sheeps' wool by Cumbria-based Second Nature. The company's just won an Ashden Award for energy efficiency, which is fitting because Thermafleece acts as an air conditioner in summer (releasing moisture and potentially reducing temperatures by 7 degrees C)  and a heater in winter (absorbing moisture and keeping temps up by 4C). It also uses much less energy to manufacture in the first place - 14 per cent of the energy required to make glass fibre. Unlike glass fibre, it doesn't require gloves and goggles to fit, as it's not full of nasty artificial irritants. You can order it direct from Second Nature and via several regional suppliers. Second Nature's website.