eVent isn't exactly the new kid on the block when it comes to waterproof membranes, its been around for a few years now and made big promises upon its release. So how has it faired?

The jacket I have been using which incorporates this membrane fabric is the Rab Latok Alpine, a very simple lightweight mountaineering hard-shell, which I found to have the best fit from other eVent Jackets which I tried. I also splashed out on a pair of the Latok Alpine trousers as matching is the in the thing this season (I also found the fit to be the best though some will probably find them a bit long in the leg).

Now I'm a fan of soft-shells personally but I also live in the Peak District which means I spend most of the winter, and a good portion of the summer, underwater and therefore if I'm going to be on the hill for any length of time I like to have something which is going to keep the rain out. I have used various Hard Shells in the past and I was often left frustrated at the lack of breathability which each and every one of them displayed. So when the eVent membrane reared its head in the UK I was eager to try one out, and I found the difference to be remarkable. eVent does breathe a lot better than any other hard shell which I have tried and the key is in the construction of the fabric.

eVent uses an expanded PTFE membrane (Polytetrafluoroethylene or Teflon to your mum - make reference to her non stick frying pans during explanation) which is the same membrane found in most hard shells, the difference being that conventional shells coat the inside of this membrane with a PU (Polyurethane) layer, to protect it from body oils which will cause the PTFE membrane to break down.

The PU layer in a conventional hard shell has to get saturated before the PTFE membrane can begin to draw the moisture to the outside of the jacket. This means that a PU coated jacket has to get a bit wet on the inside before it will start to breathe, which is something of a contradiction in terms with what the shell is trying to achieve. With the eVent membrane technology the PTFE is treated so that it doesn't require the PU coating this creates eVent's concept of direct venting, whereby there is no delay for moisture vapour trying to escape the jacket. I would readily recommend eVent to anyone looking to buy a hard shell jacket. However perhaps a better market to ask is the masses of people already using eVent membranes, having worked in a gear shop in Ambleside meant that in preparation for this review I had the best resource to call upon. I spent a couple of weeks chatting to people who walked into the shop wearing an eVent jacket, and there was an overwhelmingly positive response to the performance of the membrane. The only complaints were about stitching and DWR problems something which we will get to in a moment and these are nothing to do with the membrane whatsoever.

One of the issues relating to shell clothing which I would like to highlight is aftercare of the garment. A lot of people like to assume that their jacket will simply go on doing its job with no care or attention, that rain will bead from it surface as if it were new for it entire lifespan and that the breathability will not diminish under any circumstances. Unfortunately this is just not the case; shells require maintenance and depending on how often you use them this may have to happen more or less frequently.

DWR's (durable water repellent finishes) are what cause the rain to bead off the surface of a jacket, these wear out over time and not just through being rained on, every time a jacket rubs up against something, like the inside of your rucksack for example it damages the DWR. When the DWR begins to fail and a jacket wets out (ie. The rain stops beading and begins to soak into the outer face fabric) the membrane loses its' ability to breathe leading most to believe that their jacket is leaking, when they are actually being drenched from their own sweat as it is unable to escape. In fact somewhere in the region of 70% of hard shells returned are related to DWR failure rather than the assumption that the membrane is leaking. Washing and reproofing your shell, as necessary, will greatly improve its performance and increase its lifespan. The Latok which I have been testing eVent with, has been washed and reproofed three times in the two years that I have owned it and is due for another. You may find that it is necessary to do this more or less frequently depending on how often you use your shell. I use Nikwax Tech wash then Nikwax T.X Direct.

 
Some tips for washing and reproofing. The most important is to get rid of any normal detergent in your washing machine.

• Wash the detergent drawer with boiling water.
• Put two clean towels through a hot rinse, twice.
• Place upto two garments in your machine and then add the Tech Wash as per instructions.
• Drip dry.
• Wash garments in Nikwax T.X Direct
• Drip dry.

In conclusion, as I said earlier eVent does breathe a lot better than any other hard shell membrane I have tried. Direct venting works. With good care eVent membrane hard shells are durable. Too much venting in cold weather? I prefer to be dry and warm, rather than clammy and warm, and even in cold weather I'm usually working hard so the increased breathability compared to other breathables is not usually an issue.

For more info check out the eVent Technologies page here.

Rab have a number of eVent fabric garments available here.