Off-grid systems are not tied to any utility power lines and are most common in remote areas where connecting to the utility grid is more expensive than purchasing an off-grid system. In off-grid systems, the solar electric system represents the home’s main source of power. Batteries store unused solar energy for use at night.
Solar panels are assigned a rating in watts based on the maximum power they can produce under ideal sun and temperature conditions. You can use this rated out-put to estimate the number of panels you’ll need to meet some or all of your electricity needs. However, the exact amount of energy produced by a solar electric system also depends on roof orientation and tilt, as well as other factors such as shading, dust, panel conversion, and wire losses.