The Centre for Alternative Technology is one of the landmarks of Mid- Wales and is so well known that everyone simply calls it CAT. It was founded in 1973 by the late Gerard Morgan Grenville who set it up as a showcase for sustainable living. Now it is the first port of call for many people who want to live in a more environmentally friendly way.

Go to CAT and you can see all the latest green technology where energy can be generated by water and waves, the sun and wind. It is quite easy to imagine using any of these alternatives to fossil and nuclear fuel. However, when you ask one of the experts at CAT for the way forward, you will invariably be told to insulate your house more fully.

Insulation is the key to a greener lifestyle and the best way to cut down the fuel bills. But insulation has neither the excitement of harnessing the wind nor the cutting-edge technology of photovoltaic panels. It will, however, be the single most productive thing you can do to both cut down your carbon emissions and cushion yourself against rising fuel prices.

CAT will tell you that if your loft is uninsulated then your heating and the high bills that you pay are literally going through the roof: 25 per cent of all heat generated is lost through the roof and a further 35 per cent through the walls. If you have loft insulation, CAT will tell you to put in more. If your cavity walls aren’t insulated then they should be and if you don’t have cavity walls, then you can line the walls internally with rigid boards such as Kingspan.

CAT says that loft insulation is the simplest thing you can do and suggests that rather than follow building regulations guidelines of 250mm thickness you should aim for 350mm.

CAT has used wool insulation for its information centre and shop, pointing out that this is not a new idea, for it has been used in Wales for many centuries. Wool from Welsh hill sheep is much coarser and rougher than that of many other breeds and has traditionally been used in the carpet industry. But its coarseness and thickness make it ideal for insulation. CAT points out that very little energy is used in manufacturing woollen batts and that it is a local, renewable resource.

Natural materials

Ty-Mawr, the Brecon company that has developed a range of environmentally friendly building products, is the largest distributor for wool insulation in the country. The Gervises, who own the company, champion their product, Thermafleece, for many reasons but not least because it is a superb insulating material for old buildings. The company was born out of a love of old buildings, particularly the old farmhouse of Ty-Mawr.

When Joyce and Nigel Gervis bought Ty-Mawr, hoping to restore it as a traditional Welsh farmhouse, they discovered they couldn’t readily buy lime mortar. Their initial frustration turned to a determination to rediscover a lost natural material, and the Ty- Mawr company was born. It now supplies not only lime mortars and other traditional materials but runs courses on rendering walls with lime.

Just as they champion lime mortar they also promote wool insulation for old buildings, pointing out that it absorbs moisture in damp weather without losing its insulating property (a drawback with rock wool) and that when the air dries out, the moisture evaporates.

Normally the wool in Thermafleece, which is manufactured by Second Nature from wool supplied by the Wool Marketing Board, comes from all over the country. However, Joyce, a hill farmer’s daughter, wanted the wool supplied to Ty Mawr to reflect her Welsh roots. “It is sensible sustainability,” she says.

Both the Wool Marketing Board and Second Nature have met her request and a minimum 75 per cent of Ty Mawr’s insulation can be guaranteed to come from sheep that graze the Welsh hills.

Wool insulation costs more, but it is sound-absorbent, making it suitable not only for lofts but walls and wood planking. It can soak up and neutralise harmful toxins such as nitrogen oxide. Wool is not affected by damp and is completely safe to install. *

Newspaper pulp

The question of the safety of installing fibreglass is one that has been raised again and again. Although it has never been proved to be carcinogenic, you do need to protect yourself with a facemask and gloves when handling it. At the least, the fine and sharp filaments of fibreglass can irritate both the lungs and the skin. It is one of the primary reasons why Ben Meade turned to recycled newspaper pulp when he wanted to insulate his barn conversion near the Mid-Wales village of Meifod.

Ben had read about Warmcel recycled newspaper insulation manufactured by Excel in Gwent and thought that it sounded like a good idea. He had dismissed fibreglass as “too itchy” and thought “when you see a black cross on a product’s packaging then you should question why it’s there.”

Because Ben and his brother, Jasper, couldn’t find an installer willing to travel to Mid-Wales, the brothers decided to buy the equipment and install it themselves.

Pen y Coed, which is owned and run by the Meade brothers, is now the country’s biggest installer of this cheap and environmentally friendly material. It insulates every timber-framed building they put up – as Jasper’s background was in construction and Ben’s interest was in wood, branching out to build what Jasper calls ‘sensible houses’ was a natural development.

A ‘sensible house’ is one that is so well insulated it will cost as little as £150 a year to heat. The Meade brothers’ cluster of four houses in the Mid-Wales village of Castle Caereinion have soaring windows that overlook sheepcovered hills. Insulation is far above the government standard, and solar energy and the most efficient double-glazed windows are fitted as standard.

Their latest house is still under construction in the village of Guilsfield that lies just a few miles from the market town of Welshpool. The timber frame is up but the Warmcel has still to be blown into the foot-wide framework*. It is a good example of what an eco-house should be, as are all the houses built by the Pen y Coed workforce. The Meades are ahead of government legislation, which calls for every newly built house in Wales to be carbonneutral and carbon-free from this year onwards.

Sustainable, planet-friendly building is a subject that is dear to the heart of the Prince of Wales. Prince Charles’ own Foundation for the Built Environment is creating a low-carbon prototype made of clay blocks, rendered in lime and hemp, and insulated with wood fibre and sheep’s wool. There isn’t a windmill or any other highly priced ‘green machine’ to be seen because this house is about conserving energy reasonably which, inevitably means insulation.

*Wool insulation is fireproof and vermin-proof, non-toxic and naturally sound-absorbent. Warmcel shares all of these properties, being extremely resistant to fire through the addition of simple inorganic salts.

Further information

• Centre for Alternative Technology (CAT), Machynlleth, Powys SY20 9AZ, tel: 01654 705957 (this dedicated line offers free information on the technologies CAT promotes), www.cat.org.uk
• Ty-Mawr Lime Ltd, Ty-Mawr Farm, Llangasty, Brecon, Powys, LD3 7PJ, tel: 01874 658249, www.lime.org.uk
• Pen y Coed Construction and Insulation Ltd, Pen y Lan, Meifod, Powys SY22 6DA, tel: 01938 500643, www.penycoed-warmcel.com