In the northern hemisphere, the sun rises in the east, sets in the west, and travels in the southern portion of the sky during winter months. Therefore, it is important to select a site for your passive solar greenhouse with a clear southern exposure that receives sunlight all day during the winter months. (In the southern hemisphere the glazed surface faces north.) This configuration maximizes winter sun penetration into the greenhouse space. This means that the long side of the greenhouse should be placed along the east-west axis and the side that will be glazed will face toward the south.
This orientation optimizes the collection of the sun’s low-angle rays in the winter by increasing the area of the glazing facing the southern sky. Many conventional greenhouses do not take proper orientation into consideration when siting the greenhouse. It is estimated that changing even a conventional greenhouse from a north-south to an east-west axis can save up to 25% of the energy needed to heat and cool the space.
For best overall performance when possible, 15o east of due south is the best orientation. There should be no trees or buildings obstructing the sunlight from reaching the SunCatcher.