How Solar Panels Are Made to Function in Real World
To understand how much solar power is produced per square foot it’s helpful to know what solar panels are made of.
If a solar panel is rated to produce, say, 360 watts, and it's about 3-and- ¼-feet wide by 5-and- ½- feet long, then each square foot must produce about 20 watts, right?
Not exactly. The real test of a photovoltaic (PV) solar system is how well it works in real world conditions. To produce the maximum amount of power per square foot, a solar panel has to be well designed to handle temperature, spectrum, angle and amount of light.
Temperature: Some people associate solar power with heat because heat is associated with lots of sunlight, but if there’s too much heat, your solar panels may not work as effectively. Once temperatures rise higher than about 77 degrees Fahrenheit, there's always some drop-off in power production. Our panels have a low "temperature coefficient," or heat-related energy decline, so power production losses due to high temperatures are minimized.
Spectrum: Cloudy days are a fact of life, but – contrary to what some think – solar panels do work on cloudy days. That’s because there's a wide spectrum of light. Some of it is visible to the human eye, and some of it, like infrared and ultraviolet light, is invisible. Clouds may block a lot of the visible light, but they don't block out the entire spectrum (which, incidentally, is why you still get sunburned on a cloudy day). Our premium panels harvest more infrared and more ultraviolet light than conventional solar panels. So as a homeowner you’ll need fewer panels on your roof to produce the energy you need.
Angle: Each solar installation is unique because your home has a specific orientation to the sun. Solar installers usually install solar panels facing due south to capture the most direct sunlight. But even the sun’s rays will always hit at different angles some of the time. Most solar panels are built with "anti-reflective glass," which means once light enters the panel it will bounce back into the solar cell to harness as much power as possible. The anti-reflective glass on some panels can degrade after long exposure to weather, but our panels are known for their low degradation rate. 2 Extensively tested high-quality components like anti-reflective glass are one reason our panels have the most comprehensive complete-system warranty in the solar industry.
Amount of light: Solar panel production peaks around noon, but this can vary based on your location. Shading from trees, dust, leaves and other obstacles can obscure light, affecting solar panel power output. Shading can not only hurt power production, it can damage a solar panel over time. Most solar installers, especially Rendezvous Solar, will find a way to avoid shading to make power production efficient. And having solar panels that are 30 percent more efficient than competitors means you can use less roof space, so panels won’t have to be installed in shady spots. So how many square feet of your roof will your PV solar system cover? Because of the variables, pinning down exact numbers is tough. But at 20 watts per square foot, a system rated to produce 2 kilowatts would cover roughly 150 square feet while a 3kW system would take up about 225 square feet. Each solar installer has sophisticated software that can spell out your house's exact power needs while looking at historical weather patterns, roof angles and other factors to tell you how many panels you'll need and how much power your they'll be able to generate per square foot. When you get the solar panels installed, keep in mind that you'll want a system the system and start saving the maximum amount of money.
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