Wool vs Polyester

Wool and polyester represent the fundamental natural-vs-synthetic choice in insulating apparel fibers. Wool — primarily merino for next-to-skin garments and crossbred wools for outerwear — provides excellent thermal regulation across a wide temperature range because the fiber can absorb up to 30% of its weight in moisture vapour without feeling wet, releasing heat as it does so (heat of sorption). Polyester, a thermoplastic petroleum-derived fiber, provides insulation through loft rather than moisture absorption: it traps dead air in its structure and wicks liquid moisture to the fabric surface for evaporation. In practice, wool maintains warmth when damp and resists odour (lanolin and the fiber's scaly surface inhibit bacterial growth), while polyester dries significantly faster and is more abrasion-resistant. Cost, care, and longevity diverge sharply: polyester is machine-washable, tumble-dryable, and costs less per unit weight, while wool requires gentler laundering and carries a price premium. Blending the two fibers (e.g. 60/40 wool-polyester suiting) combines wool's drape and moisture comfort with polyester's wrinkle resistance and durability.