When to Move Reflector/Shades?

 The graph (Fig. 7) plots the months of the year according to their average temperatures and the position of the sun in the sky on the 21^st day of the month.  The sun is in the same position March 20 as September 20, yet in Albuquerque the average September temperature is 70^o F while that of March is 46^oF.  One does not switch reflector/shades on the equinoxes. Wait, maybe as long as six weeks.  The weather will tell you when to move them.

Fig. 7
Asymmetry of temperatures at equinoxes in Albuquerque, NM

I have waited as late as May to lower Sunbenders and raise drum doors, then again, I have waited as late as November to raise them. When I remember I write or scratch the date on the reflector/shade.  Each year is different; sometimes quite a lot different.

An Interesting Quality about Earth and the Length of our Year

 
The entire business of solar heating and nighttime cooling is related to the lengths of our day and our year, and the eccentricity of the earth’s orbit and the tilt of the axis of rotation.  It looks as if this was planned to embarrass architects.  Fixed overhangs could work if the year were ten times as long.  Earth temperatures would be more extreme, but temperatures would have time to keep up with changing solar positions.  And, if the year were only a month long it would be a blur of bright and dark weeks with temperatures never sinking to the depths of our winters or reaching today’s summer heats.  Fixed overhangs would again be fine. Our seasons on earth are thermal waves you must paddle to catch; you can’t wait with fixed shades to ride them.