Dissecting UNIQLO's "HeatTech"! What's the Difference Between Extra Warm, Ultra Warm, & Cashmere Blend Extra Warm?

Light, thin, soft to the touch, and exceptionally warm. UNIQLO's "HeatTech" is undeniably a winter essential nowadays.

This time, we spoke with UNIQLO's PR representative about the development story of HeatTech, its material characteristics, the differences in warmth such as Extra Warm and Ultra Warm, and the newly introduced HeatTech this season.

Aiming for a Thin, Lightweight Material that Absorbs Moisture to Generate Heat

What exactly is HeatTech?

HeatTech is a line of functional innerwear by UNIQLO, released since 2003. In addition to innerwear such as U-neck T-shirts and turtleneck T-shirts, it includes various items like tops and bottoms wearable on their own, as well as socks and gloves.

Why did UNIQLO focus on thermal innerwear?

For a long time, people used layers of clothing to keep warm. While materials like wool, fur, nylon, polyester, and down have progressed steadily, UNIQLO chose to address "cold" with a fresh approach to clothing.

Thus, we fundamentally shifted our thinking and decided to create functional innerwear that is thin, light, and warm. Naturally, to craft such innerwear, a new material was needed. We embarked on developing new materials with Japan's leading fiber company, Toray.