Solar systems are sold by kilowatt (kW), but what you actually buy is a number of panels. Here is how to go from the electricity you use to the panels on your roof.
Step 1: How big a system do you need?
In most of India, each 1 kW of panels generates roughly 4 to 5 units (kWh) a day on average across the year - more in sunny summer months, less during the monsoon. So:
- A 3 kW system makes about 12-15 units a day, or 360-450 units a month.
- A 5 kW system makes about 20-25 units a day, or 600-750 units a month.
- A 10 kW system makes about 40-50 units a day, or 1,200-1,500 units a month.
Check your electricity bill for monthly units and pick the size that covers most of them. Our solar calculator does this for you.
Step 2: Count the panels
Number of panels = system size (W) / panel wattage, rounded up. With PowerRun mono PERC panels:
| System | 550 Wp panels / 600 Wp panels |
| 3 kW | 6 panels (3.3 kWp) / 5 panels (3.0 kWp) |
| 5 kW | 10 panels (5.5 kWp) / 9 panels (5.4 kWp) |
| 10 kW | 19 panels (10.45 kWp) / 17 panels (10.2 kWp) |
Higher-wattage panels mean fewer modules, fewer mounting points and less wiring for the same output.
Step 3: Check your roof space
Plan for roughly 80-100 sq ft of shade-free roof per kW, which leaves room for spacing and walkways. A 5 kW system therefore needs around 400-500 sq ft. Avoid spots shaded by water tanks, trees or neighbouring buildings - even partial shade cuts output.
Step 4: Match the panels to your inverter
Two limits on the inverter matter:
- Maximum PV input power. The PowerRun 3.6 kW hybrid inverter accepts up to 5,000 W of panels, the 6.2 kW up to 8,500 W, and the 11 kW and 12 kW models up to 2 x 8,500 W across two MPPT inputs.
- PV input voltage range. Panels connected in series add up their voltages, and the string must stay inside the inverter's range (60-500 V DC on the 3.6 kW to 6.2 kW models). Panel voltage rises on cold mornings, so leave a margin.
Our team checks the string design for every system we supply - send us your panel count and inverter on WhatsApp.
Why mono PERC panels?
PowerRun panels use mono PERC cells with up to 21.3% module efficiency, tempered anti-reflective glass, an anodised aluminium frame and anti-PID protection. They carry a 10-year product warranty and a 25-year performance warranty. See the full range of PowerRun solar panels.
Adding a battery
A grid-tied system switches off during a power cut. Pair your panels with a hybrid inverter and a lithium battery and the sun keeps your home running through outages too.