Wind shirts; love them, hate them, think they’re an essential, or a total waste….search the various blogs out there and you’ll find someone supporting any of these positions. I guess it’s my turn to weigh in to add to the confusion, but I waited all season to come to a verdict and actually used the damn thing(s) in varying conditions.
Enlightened Equipment offers the Copperfield in three denier iterations; 20D (@1 CFM), 10D (15 CFM) and 7D (35 CFM). I’m not going to pretend to explain the science of CFM, METS and so on, there are plenty of experts out there that can do a better job than I. I can tell you this: CFM=short for cubic feet per minute (cu ft/min). It is a measurement of the velocity at which air flows into or out of a space. METS=Metabolic Equivalents, where 1 MET is the resting metabolic rate….the higher the exertion, the higher the MET. So in the EE universe, the 20D will provide the most wind protection and the 7D is the most breathable.
After scouring the web in researching and formulating a basic understanding appropriate for a music major, I determined that I would get the most use out of the 7D fabric. I’m a fairly heavy sweater, and the 35 CFM of the 7D would (theorhetically) carry me through a wide range of conditions, breathing during exertion (high METS) and providing just enough barrier in colder or windy conditions to form a layer for heat retention. Let’s look at some situations where I’ve donned this gossamer piece:
Biking: Lots of wind when you are cruising downhill at 35 MPH, and still some wind on the uphills when you are cranking. I’m not gonna stop at every hill bottom and top to don and doff a jacket. In April of 2018, I biked over 350 miles around the Olympic Peninsula, thankfully during a favorable weather window (no rain). During those times when it was too chilly for a single layer, but too warm for my biking jacket, I pulled out the miniscule EE Copperfield; not only does it weigh in at 1.91 ozs for size L, but I could cram it in small spaces on the limited real estate on my bike for easy access. And yes indeed, it provided just enough warmth in the morning and evening to keep my body temperature comfortable negotiating both uphills and downhills.