With the cost of electricity always on the rise and the cost of solar panels more affordable than ever, it's easy to consider going solar. The good news is, solar panels can be installed on most any roof, regardless of the location, type of roof and pitch. Keeping that in mind, the next question to consider is the amount of roof space required for solar panel installation. The answer to this question is far from a one-size-fits-all answer, but there are a few things to consider when sizing solar panels for your roof. Amount of Sun Exposure Not all homes are created the same, or rather, not all homes are built facing the same direction. You may have heard the old adage that your home must face south in order for solar installation to work, but this is not necessarily true. Southern exposure is ideal, but east and west facing roof surfaces are also doable. A home with plenty of sun exposure in a hotter climate typically requires less solar panels than a home facing west in the northwest part of the United States where temperatures tend to be cooler. You also have to consider the angle of your roof. While not as important as the direction your roof faces, optimal pitch is around 30 degrees. Neighboring structures, including buildings, towers and even trees reduce the efficiency of your solar panels. A shaded roof requires more solar panels to produce the same amount of energy than a shade-free roof that receives maximum sun exposure throughout the day. Efficiency Rating The average efficiency rating for solar panels in the United States is between 15 to 21 percent. High efficiency panels have a 21 to 22 percent rating, but they cost much more to install. Lower efficiency rating panels need more space for installation than higher rated panels, so if you are limited on space, you may need to install more efficient panels. When considering the efficiency rating, the same system on different roofs produce different results. Type of Roof Solar panels are heavy and require a sturdy surface. While they can be installed on any type of roof, solar panels last 30 years or more, so they require a stable surface free of cracks and other damage. A solid foundation reduces your solar panel maintenance requirements over time. Concrete roofs create little difficulties for the installation of solar panels, while metal may not be able to withstand the wind or the encumbrance. Spanish tile also requires a different type of mounting system, which can take longer to install and can increase the overall cost of installation. The type of roof you have may determine the type of panels you can install. It takes less high-efficiency panels to generate the same amount of energy as a larger number of low-efficiency panels. Thus, in order to produce enough energy and to be able to accommodate the weight of the panels, a small roof requires a smaller number of high-efficiency panels. Number of Panels Solar panels come in a variety of sizes, but the average size of a panel is approximately 3-feet by 5-feet for a total of 15-square feet. These average panels produce around 190 watts of electricity. Because electricity is measured in kilowatts per hour, you must multiply the number of watts by 1,000 to get the total number of kilowatts per hour for each panel. Therefore, the average solar panel produces .19 kilowatts of electricity. Next, you need to figure out the amount of usable roof space required for solar panels that you have on your home. The average home in the United States has around 3,000 square-foot of roof space. This doesn't take into consideration north-facing tiles, turbines and shade that subtract from the usable space. Account for the unusable space to see how many tiles your roof can accommodate. With 500 square-feet of usable roof space, you can install a 6.27 kilowatt system of 33 average-sized solar panels. Total Amount of Energy Finally, the total amount of energy your solar panels produce each year depends greatly on where you live and the cost of electricity in your area. Each area in the United States is defined by a specific weather band that details the approximate amount of solar power produced. Warmer climates generate more solar power. For example, Southeast climates fall within the 1700 kWh band. To find out the amount of energy produced, based on the 6.27 kW system, multiply the number by 1700 to get 10,659. This number is then multiplied by a constant number of .78 and you get 8,314.02 kWh of power generated per year. To calculate the savings for solar panel installation in your area, multiply the amount of power generated by the cost of electricity in your area. According to NPR, the average cost of electricity in the US is .12 cents per kWh. Thus, a 6.27 kW system with 33 panels would save you approximately $997.68 per year in energy costs. According to MIT, the average home uses 48 kWh of electricity per day. Based on that number, you would need a bigger system than the 6.27 kW system with 33 panels. Figuring out the necessary roof space required to install solar panels depends on a multitude of factors. Regardless if you want to run your home completely on solar power or if you want to see savings at the end of the year, the number of panels and the amount of roof space you need depends on where you live, the position of your home and a number of other factors.