How many solar panels do I need?
Quick answer
Divide the system size by the panel size. A 5 kW system needs about 9 panels of 585W, or about 8 panels of 645W. A 10 kW system needs about 16 to 18 panels. Bigger panels mean fewer panels on your roof.
The simple formula
Number of panels = system size (in watts) ÷ panel size (in watts). Then round up.
Example: 5 kW = 5,000 watts. With 585W panels: 5,000 ÷ 585 = 8.5, so you need about 9 panels.
Panel count for common system sizes
| System size | 585W panels | 620W panels | 645W panels |
|---|---|---|---|
| 3 kW | about 6 | about 5 | about 5 |
| 5 kW | about 9 | about 8 | about 8 |
| 8 kW | about 14 | about 13 | about 13 |
| 10 kW | about 18 | about 17 | about 16 |
Installers sometimes add one or two extra panels to make up for heat, dust and cloudy days. We will tell you the exact number for your system.
How much roof space do I need?
One modern panel of 585W to 645W takes roughly 2.5 to 3 square metres. So a 5 kW system with 9 panels needs about 25 square metres of open roof, plus some space to walk and clean. The roof should face the sun without shade from water tanks, walls or trees.
How many units will my system make?
In Punjab, each 1 kW of panels makes roughly 4 units (kWh) a day on average. It is more in sunny summer months and less in winter fog. So a 5 kW system makes about 20 units a day on average, or around 600 units a month.
What size system do I need?
Look at your electricity bill. Find how many units you use in a month, then divide by about 120 (the monthly units from 1 kW). Example: 600 units a month ÷ 120 = 5 kW.
Send us a photo of your bill on WhatsApp and we will do this for you.
Want advice for your home?
Send your electricity bill on WhatsApp and we will suggest the right system.