Men's Flannel Shirt

Flannel names a finish rather than a weave. Cotton woven plain or as a twill passes under rollers covered in fine wire. Those wires drag fiber ends up out of the surface into a soft nap. Everything the shirt does afterward comes from that raised layer.

Air held still in the nap, not the weight of the cloth, is what keeps you warm, so a napped shirt beats a smooth one of identical weight by a margin you feel at a bus stop. Shirting flannel runs 5 to 9 ounces per square yard. Single napped cloth is brushed on the face only and double napped on both sides. The second is warmer and kinder against bare skin. That nap is also the weak point, since loose fiber ends roll into pills wherever the shirt rubs, and after 20 to 30 washes it lies flat and the shirt cools down to ordinary cotton. Plaids carry their own names too: a tartan crosses bands in a repeating sequence, while a buffalo check alternates two colors in large even squares.

The Oxford Cloth Button-Down Shirt shares the shoulder seasons and none of the warmth, because nothing on it is brushed. Chambray sits thinner again. Going the other way, an Overshirt starts near 9 ounces and is cut to close over a second shirt, which flannel is not. Set against a thin wool sweater, flannel is about as warm, washes at home far more happily. Buttons open the moment a room gets hot.

Between roughly 35 and 55 degrees Fahrenheit it works alone, and below that it becomes the middle layer under a coat. Standing still outdoors is where it shows best, since trapped air does little while you move fast and everything while you wait. Heated offices are the wrong place, as the same nap holds your own heat with nowhere to send it. Wearing one under a fitted jacket adds bulk at the chest you will notice all day.

Run a palm across the inside and the outside; equal softness means both faces have been napped. Look at the plaid across the shoulder yoke and over the chest pocket, because matching a pattern there costs cloth and only careful makers pay for it. Wash inside out on a short cycle, shave pills instead of pulling them, and keep fabric softener away, since it coats the raised fibers and mats down the loft you bought.