When Berghaus claimed that they had created the world’s most breathable 3-layer GORE-TEX® jacket we couldn’t help but be excited. It’s a bold statement: the promise of lightness, waterproofing and breathability held in fine balance. As a team invested in the excellence of our outdoor gear we felt it our duty to test whether these claims held water (or, more appropriately, kept it at bay) Over the course of two cold days we donned the GR20 Storm Jacket for some fast-paced outdoor pursuits and took a serious look at whether it matched its reputation.
The first impression of the GR20 is of precision and sleek design. The woven outer material is combined with a specially constructed version of GORE-TEX® active fabric and the result is an incredibly light, almost delicate garment that feels utterly different from typical waterproof layers. The inner layer has a soft, smooth texture that feels more like natural fabric than standard synthetic. It is more than comfortable enough to be worn over just a short sleeve t-shirt.
The next-to-skin comfort is useful because the jacket’s streamlined design tapers slightly toward the waist and does not easily accommodate a chunky midlayer. This isn’t an oversight by Berghaus. The GR20 is not designed as a knockabout outer shell for long, slow treks; everything about it is focused on agility and speed. You can definitely wear it over a slim fleece but you may find yourself more commonly throwing it over the top of a baselayer for running or for high-speed hiking. And this is where that claim of superior breathability becomes a crucial issue.
Berghaus have taken two approaches to maximising temperature control. First, the main body membrane is massively breathable in itself; second, the GR20 boasts Berghaus’ Body Mapped Storm Ventilation on the chest, shoulder and underarms. The clever thing about these vents is that they open and close in accordance with body movement, so the more strenuous your activity, the more they react. A fold of material inside the vent collects any water blown up against the jacket by high winds and stops it entering through the open vent. Such a simple design detail maintains waterproofing and makes the GR20 the first open-vented jacket to pass GORE’s Storm Test. Estimates put the humidity control at 27% better than other jackets on the market.
We tested the GR20 alongside other new season shells and when it came to moving quickly up steeper terrain we found that the claims of superior breathability really did seem substantiated. Even though the day started bitterly cold, when the sun came out other waterproofs were relegated to daypacks whereas the GR20 remained comfortable throughout. Later we tested it during a short run in the hills, with the same result. Amongst all the hidden technology in contemporary outdoor gear, it’s refreshing to see something as physical and analogue as the Storm Vents, gaping to expel the heat you’re generating.
Both test days remained relatively dry so the jacket’s waterproofing capabilities were never really tested. As expected, though, what little rain we did experience caused the jacket no problems whatsoever. GORE-TEX® always provides a baseline level of reassurance and even though Berghaus have not publicly stated the hydrostatic head rating, it is estimated to be around 25,000mm. In other words, VERY waterproof.
There are lots of other design points to consider. A pair of large hip pockets offer plenty of easy storage but also contribute to ventilation. Asymmetrical, elasticated cuffs cover the back of the hands and trap warmth on colder days. The low-profile hood is lightly peaked and can be adjusted with one pull of the single adjustment toggle behind the head. The hood, like the shoulders, is also covered in a more durable version of the Active fabric to withstand the abrasion from helmets and packs.
Though these features contribute to the overall effectiveness of the jacket, our response to the GR20 was more to do with the big picture than the details. The GR20 doesn’t just offer impressive performance in a ludicrously lightweight jacket, it genuinely makes you feel more lithe, agile and capable of taking on the outdoors at speed. It may be the sleek profile, or the striking colour-blocking, or the lightweight feel, but something about wearing it promotes an eagerness to run. True, the GR20 doesn’t offer the warmth and wind-defying ruggedness of higher denier fabrics, but that isn't the point. This isn’t a jacket to protect you during the most arduous slog; it’s an outer shell to keep you mobile and motivated. We loved it.