Wool vs Cashmere for Winter: The Honest Tradeoff

Warmth for weight, and what it costs

Cashmere is about three times as warm as wool for the same weight, and that is the number that sells it. A cashmere sweater is light, soft, and warm, and it feels like nothing else on the skin. The fibres are 14 to 19 microns across, fine enough that they do not prickle, and the garment drapes instead of sitting on the body.

The price of that warmth is the animal. One goat yields 150 to 200 grams of usable fibre a year. One sheep yields 3 to 5 kilos. The raw fibre costs 80 to 200 dollars a kilo for cashmere against 3 to 15 dollars for wool, and the sweater on the shelf carries that difference: 150 to 300 dollars for cashmere, 40 to 100 for wool. The warmth is real. So is the multiplication.

Softness, and the merino exception

Softness is where cashmere's reputation comes from, and it is earned. The fine fibres do not prickle, and the fabric feels smooth against the skin in a way that coarse wool does not. A person who cannot wear wool because it itches can usually wear cashmere, and that is a real difference, not a marketing line.

But the gap has closed. Ultrafine merino under 17.5 microns rivals cashmere for softness, and a good merino sweater at a third of the price is soft enough for most people. The itch line sits around 18.5 microns, and a merino under it does not itch. Cashmere is still softer, but the difference is now a matter of degrees, and the price difference is a matter of multiples.

Wet weather, and the fibre that keeps working

Wool wins the wet weather argument, and it is not close. Wool absorbs up to 30 percent of its weight in moisture without feeling damp, and it keeps insulating while it does. A wool sweater in the rain is still a warm sweater. Cashmere loses its shape and its warmth when it gets wet, and it takes longer to dry, because the fine fibres hold water and the garment sags.

That is the practical split. A cashmere sweater is a cold, dry day garment. A wool sweater is an all weather garment. The person who walks to work in the rain needs wool. The person who sits in a heated office needs cashmere. The wardrobe that has both is the wardrobe that works in winter, and the wardrobe that has only one of them is a wardrobe with a gap.

Durability, and the honest answer

Cashmere pills more and lasts less long under hard wear, because the fibres are short and fine. Wool is tougher, and a good wool sweater will outlast a cashmere one worn the same way, in the same rotation. The cashmere sweater that gets worn once a week and rested will last years. The cashmere sweater that gets worn every day will pill in weeks and thin in a season.

The honest tradeoff is this: buy cashmere for the feeling and the warmth, and buy wool for the work. A wardrobe with two cashmere sweaters for the good days and three wool sweaters for the rest is a better wardrobe than five of either, and it costs less than five cashmere sweaters. The tradeoff is not which fibre is better. It is which job each fibre does.

Keep reading: Wool That Does Not Itch: The 18.5 Micron Rule, Linen in Winter: The Layering Trick That Actually Works, The Winter Capsule: Ten Pieces That Actually Work Together.

Frequently asked questions

Is cashmere warmer than wool?

Yes, for the same weight, about three times as warm. Cashmere fibres are 14 to 19 microns, fine enough to trap more air per gram. But wool wins when wet: it absorbs up to 30 percent of its weight in moisture without feeling damp, and it keeps insulating, while cashmere loses its shape and warmth.

Why is cashmere so much more expensive than wool?

Because the yield is tiny. One goat produces 150 to 200 grams of usable fibre a year, against 3 to 5 kilos from a sheep, and raw cashmere costs 80 to 200 dollars a kilo against 3 to 15 for wool. A cashmere sweater runs 150 to 300 dollars, a good wool sweater 40 to 100.

Does merino wool itch like regular wool?

Ultrafine merino under 17.5 microns does not itch for most people, and it rivals cashmere for softness. The itch line sits around 18.5 microns. A merino sweater under that threshold is soft enough for most skin, at a third of the cashmere price.

Which lasts longer, wool or cashmere?

Wool, under hard wear. Cashmere fibres are short and fine, so they pill more and thin faster when worn every day. A cashmere sweater worn once a week and rested for 24 to 48 hours between wears will last years, but a wool sweater worn the same way will last longer.