Power output or wattage is an important factor to consider when comparing solar panel options. You may hear your solar installer say, “it’s a 255 Watt panel” or “the panel I am recommending is has a wattage of 300.” Or, when you are reading a quote from a solar installer, you might see numbers like 245W, 300W, or 345W next to the name of the panel. They are all referring to a solar panel’s wattage, capacity and power output.

How much energy can a solar panel produce?

Available sunlight will vary depending on where you live but for the sake of an example, if you are getting 5 hours of direct sunlight in a sunny state like California you can calculate it this way: 5 hours x 290 watts (a wattage of a premium solar panel) = 1,450 watts or roughly 1.5 kilowatt-hours (kwh). Thus each solar panel in your system would produce a little over 500-550 kWh of energy per year.

All solar panels are rated by the amount of DC (direct current) power they produce under standard test conditions. Solar panel power output is expressed in units of watts (W), and represents the panel’s theoretical power production under ideal sunlight and temperature conditions. 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. Pricing in solar is typically measured in dollars per watt ($/W), and the total wattage of your solar panels plays a significant part in the overall cost of your solar system.
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