Solar Panel System Installation Guide in India

We are explaining here how to calculate and decide about the solar power plant installation. Which size solar panel you use depends mainly on how much roof space you have available and how much electricity you plan to use (with solar power). Below are 6 steps to calculate which size solar panels you need for your building.

Follow the below Steps:

>> Know your electricity usage.

>> Know your roof direction.

>> Measure roof area for solar.

>> How many panels can be fix.

>> Calculate the solar capacity.

>> Call us and get free quote.

Step 1: Know Your Electricity Usage

Gather your old electricity bills for the past 12 months. Contact your utility company if you don’t have them and your electricity provider should gladly send you a printout with your past electricity usage. You’re looking for one thing and this is your monthly unit (kWh) usage.


You can calculate as per below chart.

 Electronic WHrsQnt.Daily Use (kWh)Monthly Use (kWh)
LED Bulb20410.085.00
Washing machine1000414.0016.00
Air Conditioner 129006113.92417.60
Electric Water Heater35000.2510.8826.25
Electric Iron40210.082.40
Tumble Dryer1300415.2020.80
Vacuum Cleaner650110.652.60
Electric Oven1000.510.051.50
Electric Kettle60310.185.40
Rice Cooker200210.4012.00

Once you will get to know you monthly usage, you can easily calculate and decide your solar installation capacity.


>> Monthly usage is 600 Units (kWh)

>> Per days Usage will be 600/30 days = 20 Units

>> Accordingly your solar capacity would be 20/4 units = 5kW

1kW solar Power plant generate 4 units per day average throughout the years. So, if you will install a 5kW solar Power Plant your monthly electricity bill will be almost zero.

Step 2: Know your Roof Direction

Roof Direction idea for solar

Grab a compass (maybe your car navigation, or check Google Maps) and figure out which way is South. Go outside, look at your roof and see how much roof space is facing South, Southwest, East and West. The more South the better, but West is actually okay.

Step 3: Measure Roof Area

Roof Area estimate

Roof Area estimate for Solar calculator

Measure your available roof space facing South, SW, and/or W. There are several ways to do this, but the easiest is just to let an installer give you a free quote. You can also use Google Earth, or simply get out on your roof with measuring tape.

Step 4: Calculate How Many Solar Panels Will Fit

250w Solar panel

Now that you know how much roof you have available for solar panels and how big of a system you need, you need to determine what size panels you will need to cover your electricity usage while staying within the space you have available. Determine the number of panels you can fit on your roof by dividing your roof area (maybe 600 sq ft for a 2,000 sq ft home) by 16 square feet (500/ 16 = 31.25). Round down, as you cannot fit partial panels on your roof. So I can fit a maximum of 31 panels on my roof.

Step 5: Calculate What Size Panels You Need

5kw Solar Power Plant

5kw Solar Power Plant

Now divide the array size (of the solar electric system) you need, by the number of panels you can fit. For example, let’s say you need a 6 kW solar system to cover 90% of your electricity usage and you can fit a maximum of 31 panels on your roof. So 6,000 kW / 31 panels = 193 kW/panel. So to meet your needs, you need to use solar panels rated above 193 kW (PTC)/ panel. This means you’ll probably use panels advertised as 220 kW (STC) or higher.

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We are stockist, wholesaler, distributor for all reputed solar brands like Sukam solar, Luminius solar, Tata Solar, Exide solar,  waree solar, vikram solar, Jakson and Delta inverter, Zever SMA inverter etc. 

Author: Hari Sharan
Last Edited on 2018-01-19