What is the Heat Loss Curve?
One would assume that if you added three times the amount of insulation as you currently have, you would prevent three times the amount of heat loss, right? Well, not exactly. When you use the heat loss curve to chart the reduction of heat loss per R-value of insulation added, you see that for each unit added beyond R-20, the heat loss reductions actually diminish. Still befuddled? Take a look. The heat loss curve is simply a fancy way to illustrate the fact that increasing your insulation beyond R-20 takes far more resources than it took to reach R-20. This also means that beyond R-20 your payback on investment will take much longer. As you can see, between R-1 and R-3, each unit of R-value reduces heat loss by 4100 BTUs. But from R-21 to R-24, each additional unit of R-value only reduces 25 BTUs of heat loss. Because of this rule, in 1984, the Alberta government passed a code that stated that all new houses must be built with R20 wall insulation. This formula also gives financial cre
