1. It allowed George to write in his hut without
having to use an artificial light source. He would just get up (which was a good and healthy thing to do anyway) and give the
hut a little turn towards the light.
2. It limited the windows needed for direct light to enter the space. This is important in cold weather. More glass in the cold months made for a cooler working space. By limiting windows to one side of the shed (with only one other window opposite the door) made it possible to work in the hut even in cooler months.
3.The direct sunlight entering the hut created passive solar heating within. Limiting the windows to the one side facing the sun also reduced the amount of heat loss.
4. Last but not least, Bernard was able to pivot the hut in the summer to create a shaded space (passive shading) whenever he desired to do so. Opening the only operable window opposite the open door created natural ventilation
This just in from "Treehugger".
George Bernard Shaw