Deciding Where to Mount Your Solar Panels
After assessing your solar power needs and the amount of solar gain you can expect, you can turn your attention to mounting your solar collectors to gather as much sunlight as possible. You always have a number of choices for mounting, and the best choice depends not only on maximizing exposure over the course of a year, but also on cost and practicality. County codes require panels to withstand very high wind speeds, and conforming to this requirement can sometimes mean thousands of dollars in engineering and equipment. When all is said and done, simplicity reigns.
In most cases, you may not have much choice. If your roof faces southwest and its pitch is 45 degrees, you’ll end up mounting them on your roof, unless you want to get into some really odd-looking and expensive mounting racks. Appearance does matter, especially to the neighbors who will be looking at your solar ingenuity. When mounting racks are visible, the effect is “industrial.” Do you want your home to look like a factory?
The best orientations (in the northern hemisphere) face due south. As for altitude, the best bet is to orient the panels to the altitude of the sun in the middle of the equinoxes, or around March 20 and September 20. This angle depends on your latitude.
Identifying true south is not as simple as using a compass. Due to imperfections in the composition of the earth, due south rarely matches the compass reading. Here’s a simple way to find due south without relying on a compass or on complex “magnetic declination” formulas. Your local newspaper publishes the exact time of dawn and dusk. Calculate the middle of these times; it should be somewhere near noon, but rarely right at noon. Stick a pole in the ground, and at the exact middle time between dawn and dusk, the shadow from the pole lines up with due south.