One of the first questions every homeowner asks is: how many solar panels do I actually need? The honest answer is that you size a system by the electricity you use, not by a fixed number of panels. This guide explains how to work it out for a 3 kW, 5 kW or 10 kW system, and how many panels each needs.
Start with your bill, not the panels
Your monthly electricity bill (in units, or kWh) is the best guide to system size. As a rough rule for Rajasthan's strong sunlight, each 1 kW of solar generates about 120-140 units a month. So:
- Around 300-400 units/month suits a 3 kW system
- Around 500-600 units/month suits a 5 kW system
- Around 1,000+ units/month suits a 10 kW system
Our Solar Savings Calculator on the homepage does this for you - enter your monthly bill and it suggests a size, an estimated saving and a payback period in seconds.
How many panels is that?
Panel wattage has grown - modern panels are commonly around 540-550W each. Using ~550W panels:
- 3 kW = about 5-6 panels
- 5 kW = about 9-10 panels
- 10 kW = about 18-19 panels
If your installer uses smaller (say 400W) panels you will need a few more; larger panels, a few less. What matters is the total kW, not the exact panel count.
How much roof space you need
A useful planning figure is roughly 100 sq ft of shadow-free roof per kW:
- 3 kW - about 300 sq ft
- 5 kW - about 500 sq ft
- 10 kW - about 1,000 sq ft
The area must be free of shadow from water tanks, parapet walls or neighbouring buildings for most of the day. A site survey confirms exactly what fits.
Quick sizing guide
- 3 kW - about 5-6 panels, ~300 sq ft roof, suits a 2-3 BHK home using 300-400 units a month
- 5 kW - about 9-10 panels, ~500 sq ft, suits a larger home with air conditioning using 500-600 units
- 10 kW - about 18-19 panels, ~1,000 sq ft, suits a villa or small shop using 1,000+ units
Do not oversize or undersize
Net metering in India usually credits your daytime export against your night-time import, so a system sized close to your annual usage is ideal. Going much larger than your consumption can mean exporting units you never fully get credit for; going too small leaves you buying expensive grid power. Sizing to your actual bill gets the best payback.
Subsidy note
For homes, the PM Surya Ghar subsidy applies up to about Rs 78,000 for systems of 3 kW and above - so a 3 kW system is a popular sweet spot for Indian households. We handle the subsidy and net-metering paperwork for you.
Frequently asked questions
How many solar panels are needed for a 3 kW system?
About 5-6 panels using modern ~550W panels, needing roughly 300 sq ft of shadow-free roof. A 3 kW system suits a home using around 300-400 units a month.
How many solar panels for a 5 kW system?
Around 9-10 panels of ~550W, needing about 500 sq ft. A 5 kW system suits larger homes, especially those running air conditioning.
How do I know what size I need?
Use your monthly bill. Roughly, each 1 kW generates 120-140 units a month in Rajasthan. Our calculator turns your bill into a recommended size instantly, or request a free quote for an exact design.
Not sure which size fits your home? Get a free quote and we will size it precisely from your bill and roof.
Ready for a free solar quote?
Our team is happy to answer your questions and prepare a tailored quote.