Lessons in solar heating
When you begin to reasearch heat and energy systems for the home, it is common to hear measurements in degrees or BTUs, kilowatts or kilocals. Useful numbers to measure a system's maximum capacity, perhaps; but almost always applied as though the maximum were going to be required at all times and in all places throughout the living space.
It is similar to measuring the energy needed to move a boat through the water: I can look at the horsepower of a cruiser's twin inboard diesel engines and measure them against currents and tides, but my cruiser is the most ignorant vessel available, which burns far more fuel than required because its owner insists on traveling a straight line, across all currents and waves, at any time of day. At the helm of a sailboat, even the most amateur navigator learns quickly how to minimize the effort required to move through water, and through that learning increases his or her mastery with every voyage, until the way of being on the sea is educated by the movements of the world itself. A wise voyager spends the least to go the furthest.
In my 1860s farmhouse, there are more ways for heat to escape than there are to keep it in. I am, in effect, a sailor whose boat is full of holes, and I am constantly working against the gravity of the situation, to pour the least amount of fuel into the system, that my savings doesn't go up the chimney with the inefficiency of oil. The two heating zones in my house are both managed by automated thermostats, whose temps go down to 58 degrees during the workday and sleeping hours (I might make that lower), rising to levels of comfort considered uncomfortable by some when the house is inhabited. That's not really a matter of choice, in a building that steams through several thousand dollars a winter just to keep the pipes from bursting.
But now, let's look at this. It is knowledge about the environment and how people move through it that allow one to manage resources, instead of throwing them in the general direction of a problem, where only a fraction hit the mark. I have been sitting in my 58 degree house all morning, in front of this laptop, in complete comfort: in other words, I have spent 6 hours of "uninhabitable" oil use without feeling its lack.
What's up? Do I have a wood fire going in the little kitchen wood stove? No. Am I wearing a hat on my mostly hairless head? Not at the moment, but earlier this morning I did - at several dollars per hour in oil, it seemed a good salary for keeping a cozy lid on around the house; don't forget the woolen slippers. Do I have an electric space-heater next to my chair? No. In fact, in the living room it is almost intolerable to be seated for 15 minutes without that chill starting to go up the legs and into the fingers. But every house consists of numerous environments, the unused ones to be shut away with their volumes of icy air; the ones which serve for traffic only, from one space to another, can be left to their own devices. And this one, my eating area, is relatively cool for a working space -- the thermometer says 63.5 -- but has large windows facing south.
I don't need the cupboard doors to be warm, nor the chairs, nor the air which, when heated, becomes disagreeably dry. I don't need the there to be such a radical difference between what meets the windows from the inside and what meets the windows from wihtout. I just need me to be warm, and the full-on wash of solar heat has kept me basking all morning.
Without doubt, a newer house with a tight envelope could be kept much warmer for much less -- as an entire structure. But the ecology of an inhabited room is more important than enforcing a building-wide landscape, and on sunny winter days (of which we enjoy a good number) the akmost oil-less climate right here on this chair is frankly unbeatable. Knowing my house, or thinking about these microclimates when developing a new one, allows me to sail it smartly, in waters mild or rough.
When night comes, the heat goes down, and we do as well, not thrusting our power boats against the incoming tide, but receiving the chill as a sign that the time for bed has come. Cold, if we stay close enough to it, helps convince us not to "burn the midnight oil", as a phrase from less consumptive days would have it, but to instead burrow down into our comforters, together with the warm bodies of our partners if we have them, to enjoy the delights of a climate that is human-sized, with only human-sized demands, and human-sized expense that is easily and happily paid.