Solar panel output varies by model and ranges from around 250 to 450 Watts. The Wattage output rating represents how much energy the panel can produce per hour under standard testing conditions. In 2023, 400W panels are considered standard, so we’ll use this output for our example.
According to our calculator, a 4.5 kilowatt (kW) system with 12 panels would produce on average 4,100 kilowatt hours (kWh) in a year, enough for a 3 bedroom house. However, there are a range of factors that can affect how much electricity your solar panels produce, from the efficiency of your system to the angle of your roof.
Now we can multiply 1.75 kWh by 30 days to find that the average solar panel can produce 52.5 kWh of electricity per month. In sunny states like California, Arizona, and Florida which get around 5.25 peak sun hours per day (or more), the average 400W solar panel can produce more than 61 kWh or more of electricity per month.
A 400W solar panel receiving 4.5 peak sun hours per day can produce 1.75 kWh of AC electricity per day, as we found in the example above. Now we can multiply 1.75 kWh by 30 days to find that the average solar panel can produce 52.5 kWh of electricity per month.
The higher the wattage of a solar panel, the more electricity it can produce. The output will also be affected by the conditions, such as where you live, the angle of the roof, and the direction your home faces. A 350W solar panel will produce an average of 265 kilowatt hours (kWh) of electricity per year in the UK.
Solar panels produce different amounts of electricity depending on the season. This is because the amount of sunlight that reaches the solar panels changes throughout the year. Solar panel output is lower in the winter in the UK – by about 83%, on average.