Understanding Solar Panels: How Much Energy Does A Solar Panel Produce?

Team Solarblocks Energy
December 21, 2023
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Understanding Solar Panels: How Much Energy Does A Solar Panel Produce?

Like most Americans, you are considering switching to solar but wondering if it will be a profitable choice. Can solar panels power your entire and provide backup energy during blackouts? Can installing solar panels help save you from the towering electricity prices and bills? How much energy does a solar panel produce?

To get the answer to the last question, it is always a good practice for consumers to see if the option is worth it. You should calculate the total energy output from the solar panels and determine if it is enough to meet the long-term needs of the household.

How Much Energy Does a Solar Panel Produce?

Every solar panel owner tries to pre-define how much energy they want the solar panels to produce. Either 100% or less, the goal is to offset the electricity usage from the grid and reduce annual utility bills. 

On average, solar panels come with a 250 to 450-watt power rating and they can generate around 1.5-2 kilowatts of power every day. Most homes in the US will need about 20 panels, with an installed capacity of 6-8 kWh. However, the solar panel output depends on certain other factors too, like the roof orientation, sunlight, weather conditions, etc.

Solar Panel Output Calculation

Solar companies rate solar panels based on the amount of direct current or DC power they produce under standard test conditions. Pricing of this equipment is measured in dollars per watt ($/W) and the solar panel wattage decides the system’s overall quality and output. To calculate wattage, multiply volts x amps where volts indicate the amount of electricity force and amperes or amps indicate the aggregate energy used. 

To calculate solar panel output, consider the following. Remember, energy is the amount of power utilized in a certain period and is measured in kilowatts per hour or kWh. 

Point 1: Consider the solar panel wattage or the rating of the system. This covers the maximum energy that the solar panels can produce under ideal weather conditions. 

Point 2:  The availability of sunlight is the second most important factor to consider. Also known as solar radiance, it is the amount of sunlight reaching the surface of the solar panels. This is the solar radiance map provided by the National Renewable Energy Laboratory. You can also check the solar radiance map for the entire world

Now, multiply the solar panel wattage by the hours of sunlight received to get an estimate of the complete energy output from your system. This is the ultimate formula to know how many kwh a solar panel produces. 

Here is an example for you to understand.

If you get 6 hours of sunlight every day, you can calculate the solar panel output in the following way: 

6 hours x 250 watts (an example of solar panel wattage) = 1500 watts or 1.5 to 2 kilowatts per hour (kWh). 

If f a 300-watt solar panel receives 6 hours of sunlight on average daily, you can calculate the total energy output by: 300W x 6 hours = 1800 kWh or 1.8 kWh. Using the same calculation, if a 400 KW solar panel receives 4 hours of peak sunlight, it can produce 1.75 kWh of electricity.

Besides, it may be unclear as to how much sunlight an area receives. Hence, it is advisable to contact professional solar installers from a reputable solar company to know the sunlight availability in the region, the sun number score of the house before finally deciding on how much energy a solar panel produces.

Solar Panel Wattage Versus Solar Output

The consideration for household solar panels is never equal. Since solar panels are based on watts, the higher wattage rating means a capability for higher output. However, the solar panel’s efficiency also depends on how well they convert sunlight into energy/electricity. Although most people prefer high-rated systems, you should always choose the one that can ensure optimum power generation without hindrance. 

For example, there are two solar panels with a 25% efficiency rating. But one is a 300-watt system and the other is 450 watts. In this instance, some might assume that a 450-watt panel is more powerful depending on its size. However, it can be the opposite. This is why it is recommended to check the solar panel’s power production potential rather than its size.

Factors Which Influence the Solar Panel Output

  • Type of panel

While there are lots of options in the market, they vary depending on the wattage, efficiency ratings, and degradation rates. Silicone-based solar cells or monocrystalline panels can convert 18 and 22 percent of sunlight into usable power. High efficiency means high energy and solar panel output. On the other hand, polycrystalline panels are not efficient in comparison to Monocrystalline panels. 

  • Home roof

The output of the solar panels not only depends on the system or the solar panel wattage. The home roof is a key differentiating factor in this regard. Solar panel installation on the rooftop is effective only when the roof is southward facing with an orientation of 42 degrees. This enables optimum sunlight utilization for energy output. Hence, the home roof should be perfectly angled toward the sun. 

  • Sunlight 

How many kwh a solar panel produces largely depends on the exposure to sunlight. The more hours of sunlight, the greater the solar panel energy production. 

  • Shade

Rooftops with shade from tree branches or otherwise will lead to low solar production. The solar panel wattage ratings do not take into account the shade which blocks the sunlight. 

  • Age of the solar panels

This should not be forgotten when estimating how much energy a solar panel produces. The expected lifespan of the solar panels is 25-30 years. As they start aging, their capacity reduces and the panel output starts degrading. On average, solar panels degrade at a rate of 0.5% per year. So, once they reach their typical timeline of 25 years, the production efficiency comes to 85%. 

  • Solar panel direction

The solar panels should be placed at an angle or a vertical tilt on the roof of the house to maximize system performance. This helps the panels collect all the sunlight effectively. PV solar panels produce energy upon facing the sun directly, at an angle which is called the “angle of incidence”.  Light strikes perfectly when the panel is almost or exactly perpendicular.

Consult Solarbloks

….for professional solar panel installation and maintenance services. Here, our energy advisors can help you calculate how much energy a solar panel produces and how much kwh a solar panel produces after assessing the panel quality, wattage, house size, region, and sunlight availability. You can use our solar calculator or seek guidance before finally deciding to transition to solar. 

Get started with Solarblocks today and benefit from maximized savings.


  1. How much energy does a solar panel produce?

On average, solar panels in the US have a 250 to 450-watt power rating, capable enough to generate around 1.5-2 kilowatts of power every day. A normal house will need 20 panels, with an installed capacity of 6-8 kilowatt hours of energy. 

  1. What is the formula to calculate the total kwh of energy production from solar panels?

Calculate the total peak sunlight hours in that particular region and multiply it by the solar panel wattage. This formula will help you get an estimate of the overall energy production from the solar panels. With the result, you can estimate how many kwh a solar panel produces. 

  1. Why is the home roof an important factor to consider for solar panel efficiency?

The roof of the home is important to determine the complete usability of the solar panels. The roof should be in proper condition to bear the weight of the panels. The solar panels should be mounted securely on the roof, to face the sunlight directly for maximum energy production. They should face southward with a 30 to 45-degree tilt. A slanting roof is always beneficial for solar installation. 

  1. What do you mean by solar panel wattage?

Solar panel wattage refers to the amount of direct current or DC power that the panels produce within a particular time, under ideal conditions. It is calculated in watts, after multiplying the solar panel voltage, amperage, and the number of cells in the panel. You can also find the wattage of the panels by multiplying volts x amps where volts indicate the amount of electricity force and amps or amperes imply the aggregate energy used.

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