What do Waterproofing & Breathability Ratings Mean?
The moment you walk onto the course or step into your skis, your performance depends on more than skill and determination. It relies on the invisible science woven into every fiber of your apparel. When storm clouds gather over the fairway or fresh powder beckons from the mountain, the difference between extraordinary performance and compromised comfort often comes down to two critical measurements: waterproof and breathability ratings.
At KJUS, we don't just meet industry standards, we redefine them. To truly appreciate what sets our performance apparel apart, you need to understand the science behind these ratings and why the numbers matter more than you might think.
Decoding Waterproof Ratings: The Foundation of Protection
Waterproof ratings serve as your first line of defense against the elements, measured in millimeters of water column pressure (mm/H₂O). This rating represents exactly how much water pressure a fabric can withstand before moisture permeates the membrane of the fabric.
The measurement process is precise: imagine a graduated cylinder filled with water placed directly on the fabric. The waterproof ratings indicate how many millimeters of water must accumulate in that cylinder before the water finally permeates the membrane. A 5,000mm rating means the fabric can withstand 5,000 millimeters of water pressure before failure.
Higher numbers translate directly to superior protection. While many performance brands consider 10,000mm adequate, KJUS sets our baseline standard at 20,000mm, or double what others accept as sufficient. This isn't arbitrary ambition; it's engineered assurance that whether you're facing rain on the back nine or heavy snow on the slopes, your outerwear will keep you completely dry when others might fail.
The Science of Breathability: Beyond Simple Air Flow
Understanding breathability vs. air permeability requires recognizing an important distinction: breathability ratings measure how effectively water vapor can pass through fabric over a 24-hour period, quantified in grams per square meter per day (g/m²/24hr).
This measurement captures your body's natural moisture management system in action. As you generate heat and perspiration during movement, that moisture must escape to maintain optimal comfort and performance. Breathability ratings of 3,000-5,000 represent the low end of performance, often resulting in uncomfortable situations, when sweat has nowhere to go.
At KJUS, our baseline breathability ratings start at: 20,000g/m²/24hr. Our most advanced designs push even further, with select styles achieving 30,000, 40,000, and our pinnacle Men's Lasse Airflow Jacket reaching an extraordinary 50,000g/m²/24hr.
The Delicate Balance: Waterproofing Meets Breathability
The relationship between breathability and waterproof ratings presents one of performance apparel's greatest engineering challenges. Maximizing waterproofness traditionally compromises breathability, as the very properties that keep water out can also trap moisture inside.
This tension exists because waterproofing focuses on creating barriers, while breathability requires controlled permeability.
KJUS transcends this compromise through partnerships with cutting-edge research and development teams who engineer high-performance materials that deliver exceptional waterproof ratings while maintaining superior breathability. Our advanced fabric technologies prove that you don't have to sacrifice one for the other, you can achieve both at the highest levels.
Engineered Excellence: The Rain Gutter System
Beyond raw numbers, KJUS innovations like our rain gutter system demonstrate how thoughtful engineering amplifies performance ratings. This multi-component system uses strategically placed raised foam barriers combined with high-tech hydrophilic tape featuring a specialized finish that actively draws water toward designated channels.
Positioned near sleeve cuffs, this system guides water away from your hands, preventing the common problem of water streaming down your arms onto gloves and clubs. For golfers, this means maintaining a strong grip even in downpours.
Performance Tiers: KJUS Products by the Numbers
Our commitment to superior waterproof ratings and breathability ratings translates into real-world performance advantages across our entire line. Every adult waterproof style meets our 20,000mm baseline, for men's and women's designs.
For athletes who demand enhanced moisture management, our Golf Pro 3L 3.0 collection and Ligety series—including the Men's Ligety HexAir Jacket and Ligety Bib all feature 30,000g/m²/24hr breathability and 20,000mm waterproofness.
At the apex sits the Men's Lasse Airflow Jacket with its unprecedented 50,000g/m²/24hr breathability, engineered for the most demanding athletes who refuse to accept anything less than absolute performance supremacy.
Beyond the Numbers: The KJUS Advantage
Understanding breathability vs air permeability and the science behind the two empowers you to make informed decisions about your performance apparel. But numbers alone don't tell the complete story.
At KJUS, every rating reflects our relentless pursuit of perfection, our commitment to pushing beyond industry standards and above conventional expectations. Because when the weather turns challenging and performance matters most, you deserve apparel that exceeds every limitation others accept as inevitable.
Beyond. Above. It's not just what we believe. It's what we engineer into every fiber.