A heated vest or other type of heated clothing is very effective at replacing lost body heat. But how much heat do you really need?

Good question. In fact we need much less than we might tend to think we need. But we need it distributed more evenly. And it helps if we don't lose the heat through convection or radiation heat loss.

Heated clothing is basically an external heat source. Its effectiveness will depend on our skin's ability to absorb and transfer this heat to our deeper tissues and muscles. The problem arises in that our skin can only transfer heat at a certain rate. If we apply more, the skin exceeds its ability to transfer and it burns (or cooks, if you will).

Let's think of how we cook meat. Plop a steak on a very hot grill and it will sear on the outside while remaining raw and cold on the inside. Plop a steak on a pan that is not as hot and it will warm evenly throughout. The same holds true for electric clothing. It’s really that simple.

This is what happens when a rider feels that the heated vest is almost burning next to his skin but he is still not warm enough. This is also what happens when a rider gets branded by the heating elements. The usual suspects here are uneven heat distribution often caused by too few heating elements.

So, to my mind, the answer to how much heat is required from a heated garment is the following: Adequate levels of heat, as much as you can handle, but distributed over a greater surface will be more effective as well as more comfortable than higher but more localized levels. It's all a question of rate of absorption.

The ideal, and most comfortable for me, is a heated garment set on low simmer that soothingly replaces lost body heat.