his formula will help you figure out how many panels you’ll need to reach your energy goals.
Factors that affect how many solar panels you will need
The number of solar panels you’ll need depends on a variety of factors and is going to vary drastically by household. A few factors affecting the amount of panels you’ll need are:
- Wattage per panel
- Panel efficiency
- How much energy your solar panels are producing
- Your household’s energy consumption
- Size of the panel
- How many hours of peak sunlight you receive
- The condition and shading of your roof
- Your own personal energy goals and needs
How to calculate how many solar panels you will need
- Desired energy production (kW) / Solar panel wattage (kW) = Number of solar panels needed
- You can use this formula to calculate how many solar panels you’ll need. But first, you’ll need to know:
- Your home’s monthly energy consumption
- The wattage of the panels you plan to install
- The amount of peak sunlight hours your home receives per day
Step 1. Review your monthly electric bill: It’s important to determine how many kilowatt-hours of electricity you consume monthly. As an example, we will use 1,500 kWh every month.
Step 2. Convert monthly energy use to daily use: Given 1,500 kWh is consumed per month, to ascertain the daily usage, we need to divide this figure by the average number of days in a month, which is roughly 30.42 days (365 days divided by 12 months). Hence, the average daily use = 1,500 kWh / 30.42, approximating 49.3 kWh daily.
Step 3. Determine peak sunlight hours: This factor varies based on location and climate. For this example, let’s assume that this home receives an average of about 5 peak sunlight hours per day.
To calculate the total daily energy production required, divide the daily energy consumption by the number of peak sunlight hours. This gives the amount of energy your solar panels need to produce per day.
Energy production required = 49.3 kWh per day / 5 hours, which equals 9.86 kW.
Step 4. Calculate the number of panels: Lastly, you’ll need to determine the wattage of the solar panels you plan to install. The average solar panel efficiency in the US is rated between 250 and 400 watts. For this example, we’ll use a rating of 350 watts.
By dividing 350 by 1,000, we can convert this to kilowatts or kW. Therefore, 350 watts equals 0.35 kW.
Step 5. Determine the required number of solar panels: Divide the daily energy production needed by the solar panel’s power output.
Number of solar panels needed = 9.86 kW / 0.35 kW per panel, which equals 28.17 panels.
How much do solar panels cost in my state?
Here’s the average total cash price, cost per watt and system size for a solar panel system in your state, according to data from FindEnergy.com. These prices don’t factor in tax credits or state incentives. The grayed out states on the map don’t have any FindEnergy solar data available.
Other factors that affect how many solar panels you need
Solar panel wattage：Most residential solar panels have ratings of 250 to 400 watts.
Output efficiency
Production ratios
Panel size
Where you live and hours of sunlight
Step 1. Review your monthly electric bill: It’s important to determine how many kilowatt-hours of electricity you consume monthly. As an example, we will use 1,500 kWh every month.
Step 2. Convert monthly energy use to daily use: Given 1,500 kWh is consumed per month, to ascertain the daily usage, we need to divide this figure by the average number of days in a month, which is roughly 30.42 days (365 days divided by 12 months). Hence, the average daily use = 1,500 kWh / 30.42, approximating 49.3 kWh daily.
Step 3. Determine peak sunlight hours:This factor varies based on location and climate. For this example, let’s assume that this home receives an average of about 5 peak sunlight hours per day.
To calculate the total daily energy production required, divide the daily energy consumption by the number of peak sunlight hours. This gives the amount of energy your solar panels need to produce per day.
Energy production required = 49.3 kWh per day / 5 hours, which equals 9.86 kW.
Step 4. Calculate the number of panels:Lastly, you’ll need to determine the wattage of the solar panels you plan to install. The average solar panel efficiency in the US is rated between 250 and 400 watts. For this example, we’ll use a rating of 350 watts.
By dividing 350 by 1,000, we can convert this to kilowatts or kW. Therefore, 350 watts equals 0.35 kW.
Step 5. Determine the required number of solar panels: Divide the daily energy production needed by the solar panel’s power output.
Number of solar panels needed = 9.86 kW / 0.35 kW per panel, which equals 28.17 panels.
How much do solar panels cost in my state?
Here’s the average total cash price, cost per watt and system size for a solar panel system in your state, according to data from FindEnergy.com. These prices don’t factor in tax credits or state incentives. The grayed out states on the map don’t have any Find Energy solar data available.
Other factors that affect how many solar panels you need
Solar panel wattage: Most residential solar panels have ratings of 250 to 400 watts.
Output efficiency
Production ratios
Panel size
Where you live and hours of sunlight
Cost and budget
Annual electricity usage
Your personal solar goals