The GoLite Vapor is a very thin, full zip vest with a breathable, wind-resistant front and a non-breathable, vapor-barrier back. The principal for which it is designed is this: under very cold conditions, when you are hiking or climbing while wearing insulating clothing (e.g., fleece or high loft insulation), the vapor barrier back prevents the migration of sweat through your base layer, thus preserving the integrity of your insulation by keeping it dry.
Until we received our Vapor samples, our primary experience with zone vapor barrier vests was one with a neoprene back and fleece front. It’s weight was 10 oz, but it has gained a cult following in the climbing community for its utility during cold conditions. Thus, when we found out that GoLite was making a 2 oz zone VB vest, we jumped at the opportunity to save up to half a pound, or at least, increase the flexibility of our insulation choices (by not being locked into the insulation provided by the neoprene and fleece on the other model.
The Vapor is made with 1.4-oz silicone-coated nylon for its impermeable back and 1.1-oz uncoated ripstop nylon for its breathable front. The vest has a full zip, no collar, and is about as simple as they come. It weighs a paltry 2.1 oz, which is very near the manufacturer claim.
We used the Vapor in Montana and Alberta’s subfreezing winter backcountry while skiing and ice climbing. Below zero degrees, we found the vest to work very well, since we were wearing fleece jackets for insulation and after a long hard day, they pretty much stayed dry. However, there is no question that the vest resulted in the accumulation of moisture in the back of our base layer (resulting from sweating while wearing a backpack), so our base layer never dried out until we returned to camp and removed the vest. This caused a bit of discomfort, but never threatened to chill us to the point of hypothermia.
Therefore, we must ask the question: is it worth the discomfort of having moisture against your skin vs. in your insulating garment? For thin fleece (which breathes very well) as your insulation, the answer is probably no. However, if you are on a multi-day subzero trip where your insulation is a high-loft synthetic or down, we found the answer to be a resounding “yes!”
On a five day winter ski tour of the Canadian Rockies, where our primary insulation consisted of Polarguard-insulated parkas, which we actually wore skiing in the biting subzero winds of the Wapta Icefields, we found that using the Vapor kept our jackets puffy and warm, even though we never had the chance at night to dry out our gear (we were sleeping in snow caves rather than huts).
This is a specialized piece of equipment. It has little utility for three-season backpacking. But if you commonly venture out where the mercury drops, and you want to protect your insulating clothing on a multi-day trip, you should probably consider what this extra 2 oz can do for you. You’ll be surprised.
Final Grade: A