Let’s start with a tent. Or a tepee. Or an animal skin wrapped round the shoulders. Thin layers. Boundaries between us and inclement conditions outside.
Over time we have found ways to thicken that layer of protection. We count on that protective boundary to contain the heat our bodies generate. We build fires next, in pits first and fireplaces next and ultimately in boilers and furnaces. Understanding the effort it takes to gather and fuel that fire, or to pay to sustain it, we gain interest in preserving the effect; in sustaining the comfort we derive as long as possible, with less effort to gather the fuel – or pay for it.
The thickness of that shell, the thermal boundary that we rely on to contain the heat, has been growing slowly over the course of my building career. Following generations of hollow walls, filling that narrow framework with insulation became standard practice. In the eighties we began increasing the thickness of the walls by two inches; an idea that was considered radical at first eventually became the norm.
We now face energy and environmental realities that require us to treat our ration of energy with much greater reverence. The age of abundant cheap energy is nearing its end. Fortunately we have a provocatively simple option. Thicken the walls and use dramatically less energy to provide what turns out to be substantially better comfort.
Not only do thicker walls with more insulation require substantially less energy to provide comfort, when we take equal care to reduce air leakage the investment we make in heating that space is not suddenly exhausted thru what have historically been hundreds of air leaks in the typical home.
Thick walls, constructed without leaks, end up producing a home that is not only more energy efficient, it is healthier, more durable, comfortable, and stable than any home we have ever lived in.
How great is that!
We’re working on a house that had this “economy” insulation in its walls. Measuring an inch and a half in thickness, this insulation was doing next to nothing to preserve energy or provide comfort in this home. In the course of a remodel that is now underway we have turned the tide. We have “thickened” the building envelope in every way we know how, and we expect this home to use half the energy it once did as a result. We’re saving energy. Inch by inch!