Passive Solar- Not Sexy, Just Smart

South facing windows don't always give you the view of this photo, but any view that includes the sun for most of the day is an energy-rewarding one. There is much to know about the unfairly labeled "passive solar" approach to architecture, and I'd like to spend a few posts exploring the basics together.

Let's start with a bright morning in my addition (the photo is not mine, nor is that scrumptious view). The sun rises, depending upon the season, somewhat southeast at my latitude, 41.4 degrees north. As the sun clears the tree line, app. 500 yards from the house, four ordinary thermopane windows in the south wall start to pick up the sun. Roman shades are raised early in the morning, exposing the glass. By mid-morning, two skylights in the 45 degree sloped roof begin to cast bright, hot rectangles on the wall and floor. By now the room, underserved by my warm air heating system, is already the warmest in the house.

At noon the sun is at its highest point, and is passing the corner of the addition, which is aimed 15 degrees northeast. The house dates from about the Civil War. I didn't choose the site orientation. A four foot square casement window starts to pick up the sun and spread light across the dark harwood floor. Around two p.m. a six foot sliding glass door is filling the room with near-blinding light and more heat. It's ok, really. No one's home at that time, and I refuse to draw the curtains and lose the heat. Thou shalt not muzzle the ox, and all that Biblical wisdom.

By five p.m. it's all over. The sun reaches an artificial horizon to the southwest, a tree-lined hill that crests a quarter-mile away. And then it gets dark, we come home gratefully to a warm room, the ceiling fan has wafted lots of heat through a huge pass-through door to the rest of the house, and we drop the insulating shades and use the thermostat, if necessary, to finish heating the house for the evening. We'll be back next time to go over this scene in more detail.