Waterproof but Not Breathable? Understanding MVTR in Hardshell Jackets
1、Ever Wonder Why You’re Sweating Inside a Waterproof Jacket?
You bought a high-end waterproof jacket, expecting to stay dry. But after just a short walk or light hike, you feel hot, clammy, and wet — as if you’re sweating inside a plastic bag.
That’s because waterproofing alone isn't enough. The real key to comfort? Breathability — measured by MVTR.
2、What Is MVTR?
MVTR stands for Moisture Vapor Transmission Rate. It tells you how well a jacket can release moisture (aka your sweat) from the inside out.
Think of it this way:
Waterproofing keeps rain out. Breathability lets sweat escape.
- Unit: g/m²/24h
- Higher MVTR = better breathability
| MVTR Value | Breathability Rating |
| < 5,000 | Very poor (sweaty) |
| 10,000–15,000 | Good for moderate activity |
| ≥ 20,000 | Ideal for intense activities |
3、A jacket with weak breathability will:
- Trap sweat and feel soaked inside
- Overheat quickly during movement
- Make you feel wet, even if no rain entered
Many people mistake this for a waterproof failure — but it’s really poor breathability at fault.
4、What Affects Jacket Breathability?
- Membrane Type：Gore-Tex Active > eVent > Infinium
- Layer Construction：3-layer jackets are often more breathable than 2-layer
- Ventilation Features：Underarm zips or side vents are game-changers
- Intended Use：Hiking and snow sports demand more airflow than city wear
5、Buying Tips: Look for Both Waterproof & Breathable Performance
| Activity Type | Waterproof Need | Suggested MVTR | Best Jacket Type |
| Urban commuting | ★★☆☆☆ | 5,000–10,000 | 2-layer soft shells |
| Light hiking | ★★★☆☆ | 10,000–15,000 | 2.5-layer hardshell |
| Mountaineering/Ski | ★★★★★ | ≥ 20,000 | 3-layer w/ ventilation |
6、How to Tell If a Jacket Is Breathable?
- Look for MVTR specs (usually stated as "10,000g" or similar)
- Check for underarm zippers or mesh vents
- Read product pages from trusted brands (Gore-Tex, Polartec, etc.)
Final Thoughts
Don’t just look for waterproof ratings when choosing a hardshell jacket. Breathability makes the real difference between feeling dry and feeling drenched.
A high MVTR and good ventilation = a jacket that works as hard as you do.
Related Guides You May Like:
- 2L vs 2.5L vs 3L: Hardshell Construction Explained
- What Is Gore-Tex? Waterproof Tech 101
- How to Wash a Waterproof Jacket Without Damaging It
