Solar Panel Installation in Chennai: 3 kW vs 5 kW vs 10 kW for Your Home

Buying guide · 31 October 2026 · 8 min read

Choosing the right size for solar panel installation in Chennai is not about picking the largest system the terrace can hold. It is about matching generation to consumption so the EB bill drops without paying for capacity that gets exported at a low feed-in rate.

5 kW rooftop solar installation on a south Chennai independent house

Start with your monthly consumption

Pull twelve months of EB bills and find the average monthly units. For most Chennai households, the number falls between 150 and 600 units. The figure to match is not the peak summer month (when AC runs all day) or the lowest monsoon month — it is the annual average. Solar panel installation in Chennai should be sized for that average, not for the worst case.

What each system size generates

In Chennai's climate, a 1 kW system generates roughly 110–130 units per month on average across the year. Using 120 as a working number:

A 3 kW system generates approximately 360 units per month. This suits a household consuming 300–400 units per month — typically a 2 BHK with LED lights, fans, a refrigerator, television, and a small split AC used moderately.

A 5 kW system generates approximately 600 units per month. This suits a household consuming 500–650 units — a 3 BHK or independent house with two AC units running regularly.

A 10 kW system generates approximately 1,200 units per month. This suits a large independent house consuming 900–1,200 units per month, or a home with solar-powered water heating and an EV charger.

Terrace area required

A 3 kW system in solar panel installation in Madipakkam and south Chennai typically requires 25–30 sq metres of shadow-free terrace. A 5 kW needs 40–50 sq metres. A 10 kW needs 80–100 sq metres. These are net panel area plus structure footprint and walking clearance. If the terrace is smaller, the system is sized down to fit — not up to the ideal.

Sanctioned load matters: TANGEDCO allows a grid-tied solar system only up to the sanctioned load. A home with a 5 kW sanctioned load cannot legally install a 10 kW grid-tied system without first applying for a load enhancement.

What about the subsidy?

The PM Surya Ghar subsidy is structured so that the first 2 kW attracts the highest per-kW subsidy (₹30,000/kW), and the next 1 kW attracts a lower rate (₹18,000/kW). Above 3 kW, there is no additional subsidy. This means the subsidy incentive is highest for the first 3 kW. Many households in Chennai who consume 500 units per month still size to 5 kW for the generation benefit, understanding they will not receive additional subsidy on the last 2 kW.

When to go bigger than you need

If you plan to add an EV in the next two years, or if you are expecting higher occupancy or a second AC unit, sizing up at installation is cheaper than adding panels later. The incremental cost of going from 4 kW to 5 kW during the original installation is much lower than a second installation visit. For solar panel installation in Chennai, discuss future load changes with the site engineer during the survey. The full sizing guide covers this in more detail.