When winter bites we reach for our woollen hats, gloves, jerseys and coats, recognising they're the ultimate for warmth, even when they get a bit wet. So it has always puzzled Miles Anderson why it's only a minority who choose to wrap their houses in wool.
Anderson, who recently stepped down as Federated Farmers Meat and Wool Chairman, sees wool insulation – and carpet for that matter – as an investment in quality that will last the distance.
For a world steadily turning its back on synthetic and oil industry-based materials, wool insulation was also a green/natural choice, and one that would help the part of our agricultural sector that's doing it the hardest at the moment, Anderson said.
Anderson chose wool carpet and insulation for the new 240sqm home he's building south of Timaru - not just out of loyalty to the sheep farming industry that four generations of his family have been involved in - but because wool "ticks all the boxes".
"Wool has evolved to keep sheep comfortable in sometimes extreme conditions. It's biodegradable, renewable and sustainable."
"As wool grows, it absorbs carbon dioxide from the atmosphere. When it is finally at the end of its useful life, it readily decomposes in soil, whereas synthetics are extremely slow to degrade," Anderson said.
Wool was also a very effective insulator and acoustic buffer, durable (rated 50 years-plus in ceilings by EECA), resistant to compression and loss of "loft" (shrinkage), it exceeded other forms of insulation in absorbing sound, and was fire retardant.
Not only this, but as a result of wool's high water and nitrogen content, it won't burn unless temperatures exceed 560 degrees Celsius. If wool comes in direct contact with another burning surface, it won't melt or stick, and is self-extinguishing once the initial ignition source is removed.
Former Federated Farmers Meat and Wool Chairman Miles Anderson. Photo / Supplied
Wool forms an insulating char when it burns and emits less smoke and toxic gases during combustion than most synthetic fibres.
Terra Lana, the Christchurch company that blends wool left over from carpet and textile manufacturing with non-toxic polyester to make insulation "blankets", points out that the crimped structure of wool is extremely effective at blocking the transfer of heat by trapping air within and between its fibres.
"Wool can absorb moisture up to a quarter of its own weight as a vapour (not as a liquid), hold it within the fibres then release it as the relative humidity decreases. Synthetics and fibreglass do not have this ability and any entrapped moisture is likely to be present as a liquid or 'sweat', which can lead to mould or mildews," Terra Lana's promotional material said.
"Wool is ideal for structures made from wooden frames, as the wool has a natural synergy with timber," the guide said.
"The fibres in the material draw out moisture, which conditions the wood and protects the building's materials."
Ask a homeowner why they installed fibreglass or synthetic insulation, and chances are they'll say because it was cheaper.
Brian Murray, of Hutt Valley-based insulation manufacturer and installer Natural Wool Products, said all the superior qualities of wool justifies the price premium – "and at any rate, that premium is a bit of a myth".
"We focus on blown wool insulation, which matches or exceeds recommended R-values (a measurement of insulation effectiveness) and is excellent for getting into confined spaces under the roof.
"We can normally install it at much the same price as synthetic products," said Murray.
Although "blanket" style insulation made from wool does cost more "it pays for consumers to think about the long game".
"They really should take into account the wool product's long-livedness, and the fact it doesn't sink or slump like some of the alternatives," Murray said.
Wool is a product Kainga Ora/Housing NZ believed in, according to Murray.
"We've done the insulation in a heck of a lot of Housing NZ homes, and especially those houses which have delicate ceilings or inaccessible under-roof space. We've done hundreds of them very, very successfully."
Miles Anderson with Agriculture Minister Damien O'Connor. Photo / Supplied
In Southland, James Carter of BJ Carter Builders and Insulators - who make and install a 100 per cent natural wool ceiling insulation product, Envirowool – wished politicians would employ more action and fewer words over backing the use of New Zealand wool.
"Politicians like Winston Peters call for woollen carpets and insulation yet the government agency, the EECA, is highly particular about who gets accepted under the insulation subsidy scheme.
"Insulation companies from Christchurch, Nelson, Dunedin travel down to put in insulation in Southland homes and they qualify under the subsidy scheme. We've been in Southland for 50 years, installing wool insulation for 10 or 12 years, and we don't get a look-in in our own province.
"We're using a New Zealand product with recognised superior qualities. It's like banging our heads against a wall."
Carter believed some of the insulation products currently used in building ceilings and walls may prove to be the next asbestos.
"Silica in cement and gravel is now recognised as a problem, and I reckon fibreglass will be the next issue."
Like Miles Anderson, Carter said he was wary of any product that necessitates installers to wear personal protection equipment just to put it in place.
"In the European Union they're really cracking down on it. They've gone big on specifying cleaner, greener materials. So why are we still using these toxic products in our homes?"
