Cooling Vest Fit and Sizing: How to Size a Crew

Before you buy

Four checks, two minutes.

Flat hand

Slide a flat hand between the vest and the chest.

Fails if it slides in loose

Pinch

Try to pinch a fold of vest away from the body.

Fails if you gather material

Reach up

Raise both arms overhead, then lower them.

Fails if the hem stays up

One hour

Wear it through an hour of real work.

Fails if straps need resetting

Run these on the smallest and largest people on the crew, never someone in the middle. A size run that fits the average and fails at both ends is the most common sizing mistake in this category, and it usually gets written up as low adoption instead.

By vest type

What to watch on each.

Ice

Packs shift and sag. Check fit again once loaded, not empty.

Alternative phase change (PCM) vest, not Clema

PCM

Rigid packs bridge over curves. Look for gaps at the chest.

Evaporative

Stretches when wet. Size for soaked, not dry.

Fan

Needs air gap, not contact. Opposite rule to every other type.

Circulatory

Tubing kinks where it bends. Check seated and reaching.

A worker wearing Clema, the solid-state active cooling vest, on an industrial site

Active (Clema)

Nothing to load or soak, so the fit you set is the fit all shift. No shoulder bulk under a harness.

Full breakdown of how each type actually performs is in the cooling vest comparison and how long each one lasts.

Clema sizing

Two sizes, everyone covered.

Clema comes in two sizes rather than a long size run, because the panel adjusts across a wide range. Between them they cover the full adult range. Go by height and weight.

Size 1

Standard

Height: Under 6'1"
Weight: Under 220 lbs
Choose this if: Both are true

Size 2

Large

Height: 6'1" and over
Weight: 220 lbs and over
Choose this if: Either one is true

Over the line on either one? Take Large. A slightly larger panel that still sits flat beats a smaller one that pulls tight and gaps at the shoulders. Sizing a mixed crew and not sure of the split? Send us the range and we will work it out with you.

Layering

Second layer, always.

01Wicking base

02Cooling vest

03Work layer

04Everything else

Worn on the outside, a cooling vest has to work through whatever is underneath it, and most of the effect is lost. If it cannot get to position two, it will not get worn. How Clema cools covers why contact matters so much.

Is there a difference between cooling vests for men and women?

Most cooling vests are sold unisex, which usually means cut for a broader male torso. Cooling only transfers where the vest touches you, so a vest that gaps at the chest or rides up at the waist is cooling less of the body. Check adjustability at the shoulders and sides, and confirm the panel still sits flat on the smallest and largest people who will wear it.

Which Clema size do I need?

Clema comes in two sizes. Take Standard if you are under 6'1" and under 220 lbs. Take Large if you are 6'1" or taller, or 220 lbs or heavier. If you are over the line on either height or weight, take Large: a panel that sits flat across the torso cools better than a smaller one that pulls tight and gaps at the shoulders.

How tight should a cooling vest be?

Snug enough that the cooling panel stays against you, loose enough that it does not restrict breathing or shoulder movement. A flat hand should slide between the vest and your chest with mild resistance. If you can pinch a fold of empty vest away from your body, it is too big.

Should a cooling vest go over or under other gear?

Under. Cooling worn on the outside has to work through whatever is beneath it, which wastes most of the effect. Put a thin wicking layer against the skin, the cooling vest next, then everything else on top.

Fit is a cooling spec.