Shelter in Twilight2000

[swaghauler]

I am kicking around a short set of rules regarding "exposure" and how it affects both healing and fatigue. Twilight2K13 had a set of shelter rules but I was thinking of including clothing as well.

My "core idea" is to use a sort of "comfort threshold" of 70 degrees Fahrenheit as a base level of comfort. All coverings (blankets), clothing, sleeping bags, and shelter would "add" degrees of temperature to this threshold. I'm considering this method because most sleeping bags and tents are Rated at a given level of protection in Degrees. For instance, you can buy a +30 Degrees Sleeping bag. This means that if the outside temperature were 40 Degrees, this sleeping bag's insulation would make you feel like it was 70 degrees inside the bag. In a 100 Degree environment, that sleeping bag would make you feel too hot at a perceived temperature of 130 Degrees. This system would need ratings for mechanical effects such as heat exhaustion, and hypothermia. The most basic effect would be Fatigue. The worst case scenario would be temporary (or permanent) characteristic loss.

So, has anyone ever tried to develop these rules outside of shelter in TW2K13?