A passive solar energy system is designed to collect, store, and distribute solar energy without the aid of mechanical or electrical devices. 

Design Basics
Passive solar design is based on the following principles that optimize the use of solar energy for heating and cooling your living space: 

1. Building orientation towards true south (in the northern hemisphere)
2. Properly placed, energy efficient windows
3. Calculated roof overhangs
4. Thermal mass for energy storage
5. Thermal efficiency and insulation
6. Effective air circulation

Passive solar design uses south facing windows to bring the sun’s energy into your home. Thermal mass, such as a tiled, concrete floor, stores the heat and minimizes temperature fluctuations inside the building. Ample insulation conserves energy for both heating and cooling. That’s the concept—plain and simple.

In the winter, when the sun’s path is lower in the sky, calculated roof overhangs let the sun shine directly into the building and warm the slab. The sun’s path is higher overhead in the summer, and these same overhangs shade the windows then, keeping the sun out and your home nice and cool.

While the intent is that the house should air condition itself, as with all the house systems a back-up system must be implemented.

For more information go to the Arizona Solar Center