Are you planning on installing a Solar Power Project on your Rooftop but confused about the total Rooftop area needed to install one? Don’t worry; you have come to the right place. This article will give you a quick and easy step-by-step Guide on How to Calculate the Roof Top Area Required to Install Solar Panels for installing a fully-functional Residential Solar Project.

Find out the Number of Solar Panels Required

To find this, You need to go through the Electricity Bills of the last 12 months, in which you will find a column that shows the Electricity Units (kWh) used Every Month.

Once you have the data of the last 12 months, you need to perform the following 3 easy steps:

1. Firstly, find a Simple Average of all Monthly Consumption of Units by Adding them together and Dividing the total by 12 and you will get your Average Monthly Electricity Consumption (Units per Month) of your House.
2. Secondly, Divide the above Average Monthly Electricity Consumption (in Units) by Total Units generated by a 1 kW Solar System Per Month, and you will get the Total Size of the Solar Project (in kW)

Don’t get confused about the ‘Total Units generated by 1 kW Solar System Per Month’ As a Thumb Rule, In India, 1 kW Solar System is able to generate 4 Units of Electricity every day. Hence ‘Total Units generated by 1 kW Solar System in a Month of 30 Days’ is 120 Units (30 Days x 4 Units per Day)

• Lastly, Divide the Total Size of the Solar Project (in kW) derived in the above step by the Total Size of 1 Solar Panel, and you’ll get the Total Number of Solar Panels (in Nos.) Required.

Generally, the Total Size of 1 Solar Panel is 330 Watts or 0.33 kW. Another thing to keep in mind is that 1kW=1000 Watts.

Let’s again understand this calculation with the help of an Example.

Say, Raj’s House’s last 12 Month’s Electricity Bills show the following monthly usage:
210, 300, 400, 500, 500, 500, 600, 400, 300, 200, 200, 210 (in Units)

Hence,

• Total usage in a year (Total of all the Monthly units used) = 4320
• Total Units generated by 1 kW Solar System in a Month of 30 Days in India are120 Units
• The Total Size of 1 Solar Panel is 330 Watts or 0.33 kW

Accordingly, We will follow the 3 step guide to find the Total Number of Solar Panels required to power Raj’s House.

1. Average Monthly Electricity Consumption (in Units) = 360 Units (4320/12)
2. Total Size of the Solar Project (in kW) = 3 kW or 3000 Watts (360/120)
3. Total Number of Solar Panels (in Nos) = 09 or 9 (Approx) (3000/330)

In conclusion, Raj’s House will require a Solar Plant of 3 kW comprising 9 Solar Panels of 330 Watts each.

Find out the total Rooftop Area Required to install these Solar Panels

One Solar Panel of 330 Watts has a Standard Surface area of 20.86 sq. ft. approximately
Hence, you only need to Multiply the Surface Area of one Panel with the Total Number of Panels required for your house, and you will easily get the Total Rooftop Area required to install your Residential Solar Power Project. This area should be a Shadow-Free area, which means that it should receive direct sunlight for at least 5 hours during the day.

In the example of Raj’s House, he will need a total Rooftop Area of 187.74 sq. ft. (20.86 sq. ft. X 9 Panels)

This is the area, which is assumed as panels installed back to back and side by side to each other. However, in practical the installation is different. Practically, we have to leave the space between rows and columns of solar panels so that solar panel can be easily cleaned and for maintenance work also, there should be some space left to access the solar plant.

As a rule of thumb, we can install 1 kW of solar panels in 100 sq.ft of shadow free area on a RCC roof.

Therefore, area required for 3 kW of solar plant=3*100 sq ft=300 sq ft Now that you have understood the calculation of the estimated area required for your installation, you can accordingly proceed with your New Rooftop Solar Project. Get in touch with IB Solar to get these systems installed. Visit www.ibsolar.co.in for more information.