Take our example above, where you’re getting an average of five hours of direct sunlight per day (an average amount of sunlight for most areas of California) and using solar panels rated at 290 W. Knowing how much energy a single solar panel produces is all well and good, but more importantly, how much solar power can your roof generate? Let’s do the math below: Forget single solar panels–how much energy will your whole system produce? Pricing in solar is typically measured in dollars per watt ($/W), and your total solar panel wattage plays a significant part in the overall cost of your solar system. Most home solar panels on the market today have power output ratings ranging from 250 to 400 watts, with higher power ratings generally considered preferable to lower power ratings. Solar panel output is expressed in units of watts (W) and represents the panel’s theoretical power production under ideal sunlight and temperature conditions. Thus, the output for each solar panel in your array would produce around 500-550 kWh of energy per year.Īll solar panels are rated by the amount of DC (direct current) power they produce under standard test conditions. How much energy does a solar panel produce?įor the sake of example, if you are getting 5 hours of direct sunlight per day in a sunny state like California you can calculate your solar panel output this way: 5 hours x 290 watts (an example wattage of a premium solar panel) = 1,450 watts-hours, or roughly 1.5 kilowatt-hours (kwh). 72-cell panels are usually used on larger buildings and in commercial solar projects, not on residential homes. On the other hand, 72-cell solar panels are larger because they have an extra row of cells, and their average output is somewhere between 350 to 400 watts. Usually, 60-cell solar panels are about 5.4 feet tall by 3.25 feet wide and have an output of about 270 to 300 watts. To make things easy, we can divide solar panels into two size groups: 60-cell solar panels and 72-cell solar panels. Number of solar cells and solar panel size Higher efficiency = more energy, so high efficiency solar panels generally will have a larger energy output. Today, most solar cells can convert about 20 percent of the sunlight that hits them into usable solar energy, which has led to panels exceeding 400 watts of power. Let’s assess each factor separately to understand them a bit better. What factors determine solar panel output?īefore calculating the amount of energy a solar panel can produce, it’s important to understand the two key factors that determine its power output: cell efficiency and solar panel size. You can freely compare solar quotes on the EnergySage Marketplace to see how different wattage panels will affect your unique system.With a 30-panel system, you’ll be producing more than enough electricity per year to match all of your electricity usage, and maybe more!.Currently, most solar panels on today’s market usually produce between 250 and 400 Watts of power - your actual output will depend on factors like shading, orientation, and sun hours.