How Woollen Clothes Keep us Warm
Posted by Team NZNC on 16th Apr 2019
Wool Keeps Us Warm
Wool is one of the best insulators in the world. Just ask the sheep – you won’t hear any complaining about being cold in the winter from them.
There are few things more comforting than sinking your hands into the warm wool on the back of a sheep on a cold winter’s day. The sheep might think you’re a bit funny in the head, but if you can get close enough, it’s a lovely experience. You don’t have to risk the wild to touch a sheep, though; we’ve got plenty of types of wool for you to handle in-store…
If you do manage to make friends with a sheep, you’ll find its wool is soft and luxurious to the touch. In fact, it’s the softest natural material known to man. This comes from the lanolin in the fibres. Lanolin makes it so silky, but it also keeps it clean. It helps the wool resist dirt and grease.
Lovely lanolin is also why wool isn’t itchy. It’s far more likely to be the detergent you’ve used than the fibre itself.
Wool is so much more fun than it sounds. It’s a sustainable, water-wicking, odour-resistant, fire-resistant wonder material.
And yes – fire-resistant. Up to 600 degrees. It’s the safest fibre to have in your home. So much so that builders in NZ have been using wool insulation for years to keep buildings warm more efficiently. The rest of the world is starting to catch up!
Isn’t it interesting that the newfangled and fancy often get replaced by tried-and-tested methods we’ve been using for hundreds of years?
Just like how knitting has become trendy again, all the youngsters seem to be taking it up – our Julie could teach them a thing or two!
But what makes wool so exceptionally good at keeping us warm?
It Doesn’t Just Keep Us Warm
Wool doesn't just keep you warm.
Wearing and layering wool garments will keep you warm relative to the outside temperatures. But unlike layering with lots of cheap synthetic fabrics that make you sweat and overheat, wool helps you maintain an optimum body temperature.
Wool hair fibres act as an insulator by trapping air in the cloth. This helps regulate your temperature by acting as a natural buffer between your body and the outside of the fabric.
It also means no more having to take your layers off and then put them on again as you get hot and then cool down too rapidly, and vice versa. So your humble woolly jumper is the solution to both overheated shops and working or exercising outside on a chilly day.
Wool keeps us warm because of its amazing insulation properties, but more importantly, it helps keep our temperature constant, which keeps us nice and toasty. Not too cold, not too hot – just right.
How Wool Works
Getting a bit more nerdy, the way wool works is incredibly clever. The secret doesn’t lie in the length or thickness of the fibres. To uncover the secrets, let’s get technical:
Wool is a protein fibre formed on the skin of sheep. It’s a hygroscopic fibre, meaning that as the humidity of the air rises and falls, the fibre will absorb or release water vapour in response. This is what gives it its unique moisture-wicking properties. It holds heat during the absorptive phase of this process, which is why it’s a fabulous insulator.
The fibres themselves are crimped. Because of this irregular shape, when the fibres are tightly packed together to make fabrics, millions of tiny air pockets form. This very special structure allows the wool to absorb and release water. That water could be from you being active and getting sweaty, or from the air itself. This, combined with its hygroscopic nature, means it can maintain its thermal efficiency.
It won’t get smelly because it’s odour-resistant and, unlike synthetic fibres, won’t promote the growth of bacteria. It absorbs sweat and releases it into the air before your sweat attracts the bacteria that make it smelly. The natural waxy coating also repels stains and dust and makes it antistatic.
The unique properties don’t just stop there. The fibres are tear-resistant because of their protein composition. That means each fibre can be bent back and forth over 20,000 times without breaking. The crimped structure also means the wool has its own natural elasticity, so it will come back to shape and won’t wrinkle or sag. That’s what makes it a long-term piece of clothing you’ll love for years.
You can also dye it, and it will retain the colour without the use of chemicals because it’s hydrophilic. It’s also naturally fire-resistant up to 600 degrees, as mentioned earlier…
The especially cool thing is that we can make “warmer” and “cooler” wool fabrics. Warmth from wool depends on the construction of the yarns. A closely woven fabric of a “cool fibre” can be warmer than a not-so-closely-woven fabric of a “warmer fibre”. A textured weave may be more heat-retentive than a plain weave. This is how you get the differing wools, from smooth fabrics to the denser, tougher tweeds.
Warm Even When Wet
One of the things that helps to make wool the ultimate garment fabric is the fact that it keeps you warm even when it’s wet. It can hold 30% of its own weight in water before feeling wet and will still keep you warm.
Most know the misery of being caught in a sudden downpour in just a cotton T-shirt and jersey. You get very cold very quickly. Removing the clothes when you get in is also slightly like wrestling an octopus.
Plus, wool naturally wicks away moisture, so you don’t have a cold, wet fabric clinging to your skin. And because the wool continues to breathe, even when wet, it continues to circulate warm air around you, keeping you warm.
The price you pay for all of this is that wool does take slightly longer to dry than other fabrics. Even if you do get completely soaked through, it will still breathe and keep you warm. And that’s nothing much to grumble about, considering its phenomenal properties.
In fact, science has yet to produce a fibre with so many unique qualities. Isn’t it amazing? All from the humble sheep. There really is something to be said for sticking to the fibres nature has given us.
Looking back a bit, in 1913, William Broome had moved from the UK to Taranaki, NZ. Using felted wool, he devised the world-famous Swanndri bush shirt. Proof that time and technology have not forgotten tried-and-true wool for warmth.
What we do best is take that natural know-how and add our own to create comfortable, practical garments that last.
Making Wool Even Better
How do you make a super fibre like wool even better?
You take the only other fibre on the planet known to have the same characteristic as polar bear fur and blend it together.
That sounds crazy, right?
What kind of fibre would give you the same properties as polar bear fur? That would be the pesky common brushtail possum. New Zealand's very own seriously invasive pest. The pest that is killing ecosystems. The possum is listed as a major agricultural and conservation pest in New Zealand.
While these little blighters may look cute, they carry bovine TB, which is a major agricultural threat. Worse than that, though, they eat the eggs and chicks of the endangered kōkako, as well as the kererū, kiwi, harrier hawk, fantail, muttonbird and tūī. They also eat the plants’ nectar and berries that the native birds need to survive. To save New Zealand’s precious and fragile ecosystems, the possum has to go.
Thankfully, it is controlled, and because we’re a resourceful lot, its fibres do not go to waste. We use the fur fibres of the possum to make wool even better.
Possum fur will not freeze, even when exposed to periods of prolonged cold. It’s what makes it so similar to polar bear fur. It’s also as soft and light as silk.
The hollow nature of possum fur and superfine Merino wool makes possum Merino 14% lighter than wool, which makes it one of the most lightweight natural-fibre fabrics in the world. It is also incredibly soft, hugging the skin without itching or irritating it in any way.
Combine lovely Merino and silky possum, and you have a sustainable and environmentally beneficial super garment! One that feels lovely on, looks great for ages and has properties that science has not been able to replicate. Clothes just don’t get any better than this.
Want to see what some of these super garments look like? We’ve listed our favourites below:
Looking for Just Wool:

The Palliser Guernsey – Made from Romney lambswool, from the farm to the garment, all 100% NZ-made.
Luxurious Wool:

Luxurious base layers sit next to your skin all day. No one sees them. Once you start, you won’t be able to go without them. Julie never leaves the house without her Merino base layers.
Enhance Your Wool Experience with a Bit of Possum Added In:

The Tasman is possum-lined.
Alternatively, if you have a question about us, our products or why wool is the best thing around, get in touch and we’ll be happy to help.